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Light isovector resonances in $\pi^- p \to \pi^-\pi^-\pi^+ p$ at 190 GeV/${\it c}$
M. Aghasyan, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badelek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, et al (205)
Feb 19 2018 hep-ex hep-ph arXiv:1802.05913v2

@misc{1802.05913, author = {M.~Aghasyan and M.G.~Alexeev and G.D.~Alexeev and A.~Amoroso and V.~Andrieux and N.V.~Anfimov and V.~Anosov and A.~Antoshkin and K.~Augsten and W.~Augustyniak and A.~Austregesilo and C.D.R.~Azevedo and B.~Badelek and F.~Balestra and M.~Ball and J.~Barth and R.~Beck and Y.~Bedfer and J.~Bernhard and K.~Bicker and E.~R.~Bielert and R.~Birsa and M.~Bodlak and P.~Bordalo and F.~Bradamante and A.~Bressan and M.~Buechele and V.E.~Burtsev and W.-C.~Chang and C.~Chatterjee and M.~Chiosso and I.~Choi and A.G.~Chumakov and S.-U.~Chung and A.~Cicuttin and M.L.~Crespo and S.~Dalla Torre and S.S.~Dasgupta and S.~Dasgupta and O.Yu.~Denisov and L.~Dhara and S.V.~Donskov and N.~Doshita and Ch.~Dreisbach and W.~Duennweber and R.R.~Dusaev and M.~Dziewiecki and A.~Efremov and P.D.~Eversheim and M.~Faessler and A.~Ferrero and M.~Finger and M.~Finger jr.~and H.~Fischer and C.~Franco and N.~du Fresne von Hohenesche and J.M.~Friedrich and V.~Frolov and E.~Fuchey and F.~Gautheron and O.P.~Gavrichtchouk and S.~Gerassimov and J.~Giarra and I.~Gnesi and M.~Gorzellik and A.~Grasso and A.~Gridin and M.~Grosse Perdekamp and B.~Grube and T.~Grussenmeyer and A.~Guskov and F.~Hass and D.~Hahne and G.~Hamar and D.~von Harrach and R.~Heitz and F.~Herrmann and N.~Horikawa and N.~d'Hose and C.-Y.~Hsieh and S.~Huber and S.~Ishimoto and A.~Ivanov and Yu.~Ivanshin and T.~Iwata and V.~Jary and R.~Joosten and P.~Joerg and K.~Juraskova and E.~Kabuss and A.~Kerbizi and B.~Ketzer and G.V.~Khaustov and Yu.A.~Khokhlov and Yu.~Kisselev and F.~Klein and J.H.~Koivuniemi and V.N.~Kolosov and K.~Kondo and I.~Konorov and V.F.~Konstantinov and A.M.~Kotzinian and O.M.~Kouznetsov and Z.~Kral and M.~Kraemer and F.~Krinner and Z.V.~Kroumchtein and Y.~Kulinich and F.~Kunne and K.~Kurek and R.P.~Kurjata and I.I.~Kuznetsov and A.~Kveton and A.A.~Lednev and E.A.~Levchenko and M.~Levillain and S.~Levorato and Y.-S.~Lian and J.~Lichtenstadt and R.~Longo and V.E.~Lyubovitskij and A.~Maggiora and A.~Magnon and N.~Makins and N.~Makke and G.K.~Mallot and S.A.~Mamon and B.~Marianski and A.~Martin and J.~Marzec and J.~Matousek and H.~Matsuda and T.~Matsuda and G.V.~Meshcheryakov and M.~Meyer and W.~Meyer and Yu.V.~Mikhailov and M.~Mikhasenko and E.~Mitrofanov and N.~Mitrofanov and Y.~Miyachi and A.~Moretti and A.~Nagaytsev and F.~Nerling and D.~Neyret and J.~Novy and W.-D.~Nowak and G.~Nukazuka and A.S.~Nunes and A.G.~Olshevsky and I.~Orlov and M.~Ostrick and D.~Panzieri and B.~Parsamyan and S.~Paul and J.-C.~Peng and F.~Pereira and M.~Pesek and M.~Peskova and D.V.~Peshekhonov and N.~Pierre and S.~Platchkov and J.~Pochodzalla and V.A.~Polyakov and J.~Pretz and M.~Quaresma and C.~Quintans and S.~Ramos and C.~Regali and G.~Reicherz and C.~Riedl and N.~S.~Rogacheva and D.I.~Ryabchikov and A.~Rybnikov and A.~Rychter and R.~Salac and V.D.~Samoylenko and A.~Sandacz and C.~Santos and S.~Sarkar and I.A.~Savin and T.~Sawada and G.~Sbrizzai and P.~Schiavon and T.~Schluter and S.~Schmeing and H.~Schmieden and E.~Seder and A.~Selyunin and L.~Silva and L.~Sinha and S.~Sirtl and M.~Slunecka and J.~Smolik and A.~Srnka and D.~Steffen and M.~Stolarski and O.~Subrt and M.~Sulc and H.~Suzuki and A.~Szabelski and T.~Szameitat and P.~Sznajder and M.~Tasevsky and S.~Tessaro and F.~Tessarotto and A.~Thiel and J.~Tomsa and F.~Tosello and V.~Tskhay and S.~Uhl and B.I.~Vasilishin and A.~Vauth and B.M.~Veit and J.~Veloso and A.Vidon and M.~Virius and S.~Wallner and M.~Wilfert and J.~ter Wolbeek and K.~Zaremba and P.~Zavada and M.~Zavertyaev and E.~Zemlyanichkina and M.~Ziembicki}, title = {{L}ight isovector resonances in $\pi^- p \to \pi^-\pi^-\pi^+ p$ at 190 {G}e{V}/${\it c}$}, year = {2018}, eprint = {1802.05913}, note = {arXiv:1802.05913v2} }
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We have performed the most comprehensive resonance-model fit of $\pi^-\pi^-\pi^+$ states using the results of our previously published partial-wave analysis (PWA) of a large data set of diffractive-dissociation events from the reaction $\pi^- + p \to \pi^-\pi^-\pi^+ + p_\text{recoil}$ with a 190 GeV/$c$ pion beam. The PWA results, which were obtained in 100 bins of three-pion mass, $0.5 < m_{3\pi} < 2.5$ GeV/$c^2$, and simultaneously in 11 bins of the reduced four-momentum transfer squared, $0.1 < t' < 1.0$ $($GeV$/c)^2$, are subjected to a resonance-model fit using Breit-Wigner amplitudes to simultaneously describe a subset of 14 selected waves using 11 isovector light-meson states with $J^{PC} = 0^{-+}$, $1^{++}$, $2^{++}$, $2^{-+}$, $4^{++}$, and spin-exotic $1^{-+}$ quantum numbers. The model contains the well-known resonances $\pi(1800)$, $a_1(1260)$, $a_2(1320)$, $\pi_2(1670)$, $\pi_2(1880)$, and $a_4(2040)$. In addition, it includes the disputed $\pi_1(1600)$, the excited states $a_1(1640)$, $a_2(1700)$, and $\pi_2(2005)$, as well as the resonancelike $a_1(1420)$. We measure the resonance parameters mass and width of these objects by combining the information from the PWA results obtained in the 11 $t'$ bins. We extract the relative branching fractions of the $\rho(770) \pi$ and $f_2(1270) \pi$ decays of $a_2(1320)$ and $a_4(2040)$, where the former one is measured for the first time. In a novel approach, we extract the $t'$ dependence of the intensity of the resonances and of their phases. The $t'$ dependence of the intensities of most resonances differs distinctly from the $t'$ dependence of the nonresonant components. For the first time, we determine the $t'$ dependence of the phases of the production amplitudes and confirm that the production mechanism of the Pomeron exchange is common to all resonances.
Longitudinal double-spin asymmetry $A_1^{\rm p}$ and spin-dependent structure function $g_1^{\rm p}$ of the proton at small values of $x$ and $Q^2$
M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badelek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, et al (209)
Oct 04 2017 hep-ex arXiv:1710.01014v1

@misc{1710.01014, author = {M.~Aghasyan and R.~Akhunzyanov and M.G.~Alexeev and G.D.~Alexeev and A.~Amoroso and V.~Andrieux and N.V.~Anfimov and V.~Anosov and A.~Antoshkin and K.~Augsten and W.~Augustyniak and A.~Austregesilo and C.D.R.~Azevedo and B.~Badelek and F.~Balestra and M.~Ball and J.~Barth and R.~Beck and Y.~Bedfer and J.~Bernhard and K.~Bicker and E.~R.~Bielert and R.~Birsa and M.~Bodlak and P.~Bordalo and F.~Bradamante and A.~Bressan and M.~Buechele and V.E.~Burtsev and W.-C.~Chang and C.~Chatterjee and M.~Chiosso and I.~Choi and A.G.~Chumakov and S.-U.~Chung and A.~Cicuttin and M.L.~Crespo and S.~Dalla Torre and S.S.~Dasgupta and S.~Dasgupta and O.Yu.~Denisov and L.~Dhara and S.V.~Donskov and N.~Doshita and Ch.~Dreisbach and W.~Duennweber and R.R.~Dusaev and M.~Dziewiecki and A.~Efremov and P.D.~Eversheim and M.~Faessler and A.~Ferrero and M.~Finger and M.~Finger jr.~and H.~Fischer and C.~Franco and N.~du Fresne von Hohenesche and J.M.~Friedrich and V.~Frolov and E.~Fuchey and F.~Gautheron and O.P.~Gavrichtchouk and S.~Gerassimov and J.~Giarra and F.~Giordano and I.~Gnesi and M.~Gorzellik and A.~Grasso and A.~Gridin and M.~Grosse Perdekamp and B.~Grube and T.~Grussenmeyer and A.~Guskov and D.~Hahne and G.~Hamar and D.~von Harrach and F.H.~Heinsius and R.~Heitz and F.~Herrmann and N.~Horikawa and N.~d'Hose and C.-Y.~Hsieh and S.~Huber and S.~Ishimoto and A.~Ivanov and Yu.~Ivanshin and T.~Iwata and V.~Jary and R.~Joosten and P.~Joerg and E.~Kabuss and A.~Kerbizi and B.~Ketzer and G.V.~Khaustov and Yu.A.~Khokhlov and Yu.~Kisselev and F.~Klein and J.H.~Koivuniemi and V.N.~Kolosov and K.~Kondo and K.~Koenigsmann and I.~Konorov and V.F.~Konstantinov and A.M.~Kotzinian and O.M.~Kouznetsov and Z.~Kral and M.~Kraemer and P.~Kremser and F.~Krinner and Z.V.~Kroumchtein and Y.~Kulinich and F.~Kunne and K.~Kurek and R.P.~Kurjata and I.I.~Kuznetsov and A.~Kveton and A.A.~Lednev and E.A.~Levchenko and M.~Levillain and S.~Levorato and Y.-S.~Lian and J.~Lichtenstadt and R.~Longo and V.E.~Lyubovitskij and A.~Maggiora and A.~Magnon and N.~Makins and N.~Makke and G.K.~Mallot and S.A.~Mamon and B.~Marianski and A.~Martin and J.~Marzec and J.~Matousek and H.~Matsuda and T.~Matsuda and G.V.~Meshcheryakov and M.~Meyer and W.~Meyer and Yu.V.~Mikhailov and M.~Mikhasenko and E.~Mitrofanov and N.~Mitrofanov and Y.~Miyachi and A.~Moretti and A.~Nagaytsev and F.~Nerling and D.~Neyret and J.~Novy and W.-D.~Nowak and G.~Nukazuka and A.S.~Nunes and A.G.~Olshevsky and I.~Orlov and M.~Ostrick and D.~Panzieri and B.~Parsamyan and S.~Paul and J.-C.~Peng and F.~Pereira and M.~Pesek and M.~Peskova and D.V.~Peshekhonov and N.~Pierre and S.~Platchkov and J.~Pochodzalla and V.A.~Polyakov and J.~Pretz and M.~Quaresma and C.~Quintans and S.~Ramos and C.~Regali and G.~Reicherz and C.~Riedl and N.S.~Rogacheva and D.I.~Ryabchikov and A.~Rybnikov and A.~Rychter and R.~Salac and V.D.~Samoylenko and A.~Sandacz and C.~Santos and S.~Sarkar and I.A.~Savin and T.~Sawada and G.~Sbrizzai and P.~Schiavon and K.~Schmidt and H.~Schmieden and K.~Schoenning and E.~Seder and A.~Selyunin and L.~Silva and L.~Sinha and S.~Sirtl and M.~Slunecka and J.~Smolik and A.~Srnka and D.~Steffen and M.~Stolarski and O.~Subrt and M.~Sulc and H.~Suzuki and A.~Szabelski and T.~Szameitat and P.~Sznajder and M.~Tasevsky and S.~Tessaro and F.~Tessarotto and A.~Thiel and J.~Tomsa and F.~Tosello and V.~Tskhay and S.~Uhl and B.I.~Vasilishin and A.~Vauth and J.~Veloso and A.Vidon and M.~Virius and S.~Wallner and T.~Weisrock and M.~Wilfert and J.~ter Wolbeek and K.~Zaremba and P.~Zavada and M.~Zavertyaev and E.~Zemlyanichkina and N.~Zhuravlev and M.~Ziembicki}, title = {{L}ongitudinal double-spin asymmetry ${A}_1^{\rm p}$ and spin-dependent structure function $g_1^{\rm p}$ of the proton at small values of $x$ and ${Q}^2$}, year = {2017}, eprint = {1710.01014}, note = {arXiv:1710.01014v1} }
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We present a precise measurement of the proton longitudinal double-spin asymmetry $A_1^{\rm p}$ and the proton spin-dependent structure function $g_1^{\rm p}$ at photon virtualities $0.006~({\rm GeV}/c)^2<Q^2 < 1~({\rm GeV}/c)^2$ in the Bjorken $x$ range of $4 \times 10^{-5} < x < 4 \times 10^{-2}$. The results are based on data collected by the COMPASS Collaboration at CERN using muon beam energies of $160~{\rm GeV}$ and $200~{\rm GeV}$. The statistical precision is more than tenfold better than that of the previous measurement in this region. In the whole range of $x$, the measured values of $A_1^{\rm p}$ and $g_1^{\rm p}$ are found to be positive. It is for the first time that spin effects are found at such low values of $x$.
Transverse-momentum-dependent Multiplicities of Charged Hadrons in Muon-Deuteron Deep Inelastic Scattering
M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badelek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, et al (211)
Sep 22 2017 hep-ex nucl-ex arXiv:1709.07374v1

@misc{1709.07374, author = {M.~Aghasyan and R.~Akhunzyanov and M.G.~Alexeev and G.D.~Alexeev and A.~Amoroso and V.~Andrieux and N.V.~Anfimov and V.~Anosov and A.~Antoshkin and K.~Augsten and W.~Augustyniak and A.~Austregesilo and C.D.R.~Azevedo and B.~Badelek and F.~Balestra and M.~Ball and J.~Barth and R.~Beck and Y.~Bedfer and J.~Bernhard and K.~Bicker and E.~R.~Bielert and R.~Birsa and M.~Bodlak and P.~Bordalo and F.~Bradamante and A.~Bressan and M.~Buechele and V.E.~Burtsev and L.~Capozza and W.-C.~Chang and C.~Chatterjee and M.~Chiosso and I.~Choi and A.G.~Chumakov and S.-U.~Chung and A.~Cicuttin and M.L.~Crespo and Q.~Curiel and S.~Dalla Torre and S.S.~Dasgupta and S.~Dasgupta and O.Yu.~Denisov and L.~Dhara and S.V.~Donskov and N.~Doshita and Ch.~Dreisbach and W.~Duennweber and R.R.~Dusaev and M.~Dziewiecki and A.~Efremov and P.D.~Eversheim and M.~Faessler and A.~Ferrero and M.~Finger and M.~Finger jr.~and H.~Fischer and C.~Franco and N.~du Fresne von Hohenesche and J.M.~Friedrich and V.~Frolov and E.~Fuchey and F.~Gautheron and O.P.~Gavrichtchouk and S.~Gerassimov and J.~Giarra and F.~Giordano and I.~Gnesi and M.~Gorzellik and A.~Grasso and A.~Gridin and M.~Grosse Perdekamp and B.~Grube and T.~Grussenmeyer and A.~Guskov and D.~Hahne and G.~Hamar and D.~von Harrach and F.H.~Heinsius and R.~Heitz and F.~Herrmann and N.~Horikawa and N.~d'Hose and C.-Y.~Hsieh and S.~Huber and S.~Ishimoto and A.~Ivanov and Yu.~Ivanshin and T.~Iwata and V.~Jary and R.~Joosten and P.~Joerg and E.~Kabuss and A.~Kerbizi and B.~Ketzer and G.V.~Khaustov and Yu.A.~Khokhlov and Yu.~Kisselev and F.~Klein and J.H.~Koivuniemi and V.N.~Kolosov and K.~Kondo and K.~Koenigsmann and I.~Konorov and V.F.~Konstantinov and A.M.~Kotzinian and O.M.~Kouznetsov and Z.~Kral and M.~Kraemer and P.~Kremser and F.~Krinner and Z.V.~Kroumchtein and Y.~Kulinich and F.~Kunne and K.~Kurek and R.P.~Kurjata and I.I.~Kuznetsov and A.~Kveton and A.A.~Lednev and E.A.~Levchenko and M.~Levillain and S.~Levorato and Y.-S.~Lian and J.~Lichtenstadt and R.~Longo and V.E.~Lyubovitskij and A.~Maggiora and A.~Magnon and N.~Makins and N.~Makke and G.K.~Mallot and S.A.~Mamon and B.~Marianski and A.~Martin and J.~Marzec and J.~Matousek and H.~Matsuda and T.~Matsuda and G.V.~Meshcheryakov and M.~Meyer and W.~Meyer and Yu.V.~Mikhailov and M.~Mikhasenko and E.~Mitrofanov and N.~Mitrofanov and Y.~Miyachi and A.~Moretti and A.~Nagaytsev and F.~Nerling and D.~Neyret and J.~Novy and W.-D.~Nowak and G.~Nukazuka and A.S.~Nunes and A.G.~Olshevsky and I.~Orlov and M.~Ostrick and D.~Panzieri and B.~Parsamyan and S.~Paul and J.-C.~Peng and F.~Pereira and M.~Pesek and M.~Peskova and D.V.~Peshekhonov and N.~Pierre and S.~Platchkov and J.~Pochodzalla and V.A.~Polyakov and J.~Pretz and M.~Quaresma and C.~Quintans and S.~Ramos and C.~Regali and G.~Reicherz and C.~Riedl and N.S.~Rogacheva and D.I.~Ryabchikov and A.~Rybnikov and A.~Rychter and R.~Salac and V.D.~Samoylenko and A.~Sandacz and C.~Santos and S.~Sarkar and I.A.~Savin and T.~Sawada and G.~Sbrizzai and P.~Schiavon and K.~Schmidt and H.~Schmieden and K.~Schoenning and E.~Seder and A.~Selyunin and L.~Silva and L.~Sinha and S.~Sirtl and M.~Slunecka and J.~Smolik and A.~Srnka and D.~Steffen and M.~Stolarski and O.~Subrt and M.~Sulc and H.~Suzuki and A.~Szabelski and T.~Szameitat and P.~Sznajder and M.~Tasevsky and S.~Tessaro and F.~Tessarotto and A.~Thiel and J.~Tomsa and F.~Tosello and V.~Tskhay and S.~Uhl and B.I.~Vasilishin and A.~Vauth and J.~Veloso and A.Vidon and M.~Virius and S.~Wallner and T.~Weisrock and M.~Wilfert and J.~ter Wolbeek and K.~Zaremba and P.~Zavada and M.~Zavertyaev and E.~Zemlyanichkina and N.~Zhuravlev and M.~Ziembicki}, title = {{T}ransverse-momentum-dependent {M}ultiplicities of {C}harged {H}adrons in {M}uon-{D}euteron {D}eep {I}nelastic {S}cattering}, year = {2017}, eprint = {1709.07374}, note = {arXiv:1709.07374v1} }
PDF
A semi-inclusive measurement of charged hadron multiplicities in deep inelastic muon scattering off an isoscalar target was performed using data collected by the COMPASS Collaboration at CERN. The following kinematic domain is covered by the data: photon virtuality $Q^{2}>1$ (GeV/$c$)$^2$, invariant mass of the hadronic system $W > 5$ GeV/$c^2$, Bjorken scaling variable in the range $0.003 < x < 0.4$, fraction of the virtual photon energy carried by the hadron in the range $0.2 < z < 0.8$, square of the hadron transverse momentum with respect to the virtual photon direction in the range 0.02 (GeV/$c)^2 < P_{\rm{hT}}^{2} < 3$ (GeV/$c$)$^2$. The multiplicities are presented as a function of $P_{\rm{hT}}^{2}$ in three-dimensional bins of $x$, $Q^2$, $z$ and compared to previous semi-inclusive measurements. We explore the small-$P_{\rm{hT}}^{2}$ region, i.e. $P_{\rm{hT}}^{2} < 1$ (GeV/$c$)$^2$, where hadron transverse momenta are expected to arise from non-perturbative effects, and also the domain of larger $P_{\rm{hT}}^{2}$, where contributions from higher-order perturbative QCD are expected to dominate. The multiplicities are fitted using a single-exponential function at small $P_{\rm{hT}}^{2}$ to study the dependence of the average transverse momentum $\langle P_{\rm{hT}}^{2}\rangle$ on $x$, $Q^2$ and $z$. The power-law behaviour of the multiplicities at large $P_{\rm{hT}}^{2}$ is investigated using various functional forms. The fits describe the data reasonably well over the full measured range.
New analysis of $\eta\pi$ tensor resonances measured at the COMPASS experiment
A. Jackura, C. Fernandez-Ramirez, M. Mikhasenko, A. Pilloni, V. Mathieu, J. Nys, V. Pauk, A. P. Szczepaniak, G. Fox, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, et al (217)
Jul 11 2017 hep-ph hep-ex arXiv:1707.02848v1

@misc{1707.02848, author = {A.~Jackura and C.~Fernandez-Ramirez and M.~Mikhasenko and A.~Pilloni and V.~Mathieu and J.~Nys and V.~Pauk and A.~P.~Szczepaniak and G.~Fox and M.~Aghasyan and R.~Akhunzyanov and M.G.~Alexeev and G.D.~Alexeev and A.~Amoroso and V.~Andrieux and N.V.~Anfimov and V.~Anosov and A.~Antoshkin and K.~Augsten and W.~Augustyniak and A.~Austregesilo and C.D.R.~Azevedo and B.~Badelek and F.~Balestra and M.~Ball and J.~Barth and R.~Beck and Y.~Bedfer and J.~Bernhard and K.~Bicker and E.~R.~Bielert and R.~Birsa and M.~Bodlak and P.~Bordalo and F.~Bradamante and A.~Bressan and M.~Buechele and V.E.~Burtsev and W.-C.~Chang and C.~Chatterjee and M.~Chiosso and I.~Choi and A.G.~Chumakov and S.-U.~Chung and A.~Cicuttin and M.L.~Crespo and S.~Dalla Torre and S.S.~Dasgupta and S.~Dasgupta and O.Yu.~Denisov and L.~Dhara and S.V.~Donskov and N.~Doshita and Ch.~Dreisbach and W.~Duennweber and R.R.~Dusaev and M.~Dziewiecki and A.~Efremov and P.D.~Eversheim and M.~Faessler and A.~Ferrero and M.~Finger and M.~Finger jr.~and H.~Fischer and C.~Franco and N.~du Fresne von Hohenesche and J.M.~Friedrich and V.~Frolov and E.~Fuchey and F.~Gautheron and O.P.~Gavrichtchouk and S.~Gerassimov and J.~Giarra and F.~Giordano and I.~Gnesi and M.~Gorzellik and A.~Grasso and M.~Grosse Perdekamp and B.~Grube and T.~Grussenmeyer and A.~Guskov and D.~Hahne and G.~Hamar and D.~von Harrach and F.H.~Heinsius and R.~Heitz and F.~Herrmann and N.~Horikawa and N.~d'Hose and C.-Y.~Hsieh and S.~Huber and S.~Ishimoto and A.~Ivanov and Yu.~Ivanshin and T.~Iwata and V.~Jary and R.~Joosten and P.~Joerg and E.~Kabuss and A.~Kerbizi and B.~Ketzer and G.V.~Khaustov and Yu.A.~Khokhlov and Yu.~Kisselev and F.~Klein and J.H.~Koivuniemi and V.N.~Kolosov and K.~Kondo and K.~Koenigsmann and I.~Konorov and V.F.~Konstantinov and A.M.~Kotzinian and O.M.~Kouznetsov and Z.~Kral and M.~Kraemer and P.~Kremser and F.~Krinner and Z.V.~Kroumchtein and Y.~Kulinich and F.~Kunne and K.~Kurek and R.P.~Kurjata and I.I.~Kuznetsov and A.~Kveton and A.A.~Lednev and E.A.~Levchenko and M.~Levillain and S.~Levorato and Y.-S.~Lian and J.~Lichtenstadt and R.~Longo and V.E.~Lyubovitskij and A.~Maggiora and A.~Magnon and N.~Makins and N.~Makke and G.K.~Mallot and S.A.~Mamon and B.~Marianski and A.~Martin and J.~Marzec and J.~Matousek and H.~Matsuda and T.~Matsuda and G.V.~Meshcheryakov and M.~Meyer and W.~Meyer and Yu.V.~Mikhailov and M.~Mikhasenko and E.~Mitrofanov and N.~Mitrofanov and Y.~Miyachi and A.~Nagaytsev and F.~Nerling and D.~Neyret and J.~Novy and W.-D.~Nowak and G.~Nukazuka and A.S.~Nunes and A.G.~Olshevsky and I.~Orlov and M.~Ostrick and D.~Panzieri and B.~Parsamyan and S.~Paul and J.-C.~Peng and F.~Pereira and M.~Pesek and M.~Peskova and D.V.~Peshekhonov and N.~Pierre and S.~Platchkov and J.~Pochodzalla and V.A.~Polyakov and J.~Pretz and M.~Quaresma and C.~Quintans and S.~Ramos and C.~Regali and G.~Reicherz and C.~Riedl and N.S.~Rogacheva and D.I.~Ryabchikov and A.~Rybnikov and A.~Rychter and R.~Salac and V.D.~Samoylenko and A.~Sandacz and C.~Santos and S.~Sarkar and I.A.~Savin and T.~Sawada and G.~Sbrizzai and P.~Schiavon and T.~Schluter and K.~Schmidt and H.~Schmieden and K.~Schoenning and E.~Seder and A.~Selyunin and L.~Silva and L.~Sinha and S.~Sirtl and M.~Slunecka and J.~Smolik and A.~Srnka and D.~Steffen and M.~Stolarski and O.~Subrt and M.~Sulc and H.~Suzuki and A.~Szabelski and T.~Szameitat and P.~Sznajder and M.~Tasevsky and S.~Tessaro and F.~Tessarotto and A.~Thiel and J.~Tomsa and F.~Tosello and V.~Tskhay and S.~Uhl and B.I.~Vasilishin and A.~Vauth and J.~Veloso and A.Vidon and M.~Virius and S.~Wallner and T.~Weisrock and M.~Wilfert and J.~ter Wolbeek and K.~Zaremba and P.~Zavada and M.~Zavertyaev and E.~Zemlyanichkina and N.~Zhuravlev and M.~Ziembicki}, title = {{N}ew analysis of $\eta\pi$ tensor resonances measured at the {COMPASS} experiment}, year = {2017}, eprint = {1707.02848}, note = {arXiv:1707.02848v1} }
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We present a new amplitude analysis of the $\eta\pi$ $D$-wave in $\pi^- p\to \eta\pi^- p$ measured by COMPASS. Employing an analytical model based on the principles of the relativistic $S$-matrix, we find two resonances that can be identified with the $a_2(1320)$ and the excited $a_2^\prime(1700)$, and perform a comprehensive analysis of their pole positions. For the mass and width of the $a_2$ we find $M=(1307 \pm 1 \pm 6)$~MeV and $\Gamma=(112 \pm 1 \pm 8)$~MeV, and for the excited state $a_2^\prime$ we obtain $M=(1720 \pm 10 \pm 60)$~MeV and $\Gamma=(280\pm 10 \pm 70)$~MeV, respectively.
Search for muoproduction of $X(3872)$ at COMPASS and indication of a new state $\widetilde{X}(3872)$
M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badelek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, et al (208)
Jul 07 2017 hep-ex arXiv:1707.01796v2

@misc{1707.01796, author = {M.~Aghasyan and R.~Akhunzyanov and M.G.~Alexeev and G.D.~Alexeev and A.~Amoroso and V.~Andrieux and N.V.~Anfimov and V.~Anosov and A.~Antoshkin and K.~Augsten and W.~Augustyniak and A.~Austregesilo and C.D.R.~Azevedo and B.~Badelek and F.~Balestra and M.~Ball and J.~Barth and R.~Beck and Y.~Bedfer and J.~Bernhard and K.~Bicker and E.~R.~Bielert and R.~Birsa and M.~Bodlak and P.~Bordalo and F.~Bradamante and A.~Bressan and M.~Buechele and V.E.~Burtsev and W.-C.~Chang and C.~Chatterjee and M.~Chiosso and I.~Choi and A.G.~Chumakov and S.-U.~Chung and A.~Cicuttin and M.L.~Crespo and S.~Dalla Torre and S.S.~Dasgupta and S.~Dasgupta and O.Yu.~Denisov and L.~Dhara and S.V.~Donskov and N.~Doshita and Ch.~Dreisbach and W.~Duennweber and R.R.~Dusaev and M.~Dziewiecki and A.~Efremov and P.D.~Eversheim and M.~Faessler and A.~Ferrero and M.~Finger and M.~Finger jr.~and H.~Fischer and C.~Franco and N.~du Fresne von Hohenesche and J.M.~Friedrich and V.~Frolov and E.~Fuchey and F.~Gautheron and O.P.~Gavrichtchouk and S.~Gerassimov and J.~Giarra and F.~Giordano and I.~Gnesi and M.~Gorzellik and A.~Grasso and A.~Gridin and M.~Grosse Perdekamp and B.~Grube and T.~Grussenmeyer and A.~Guskov and D.~Hahne and G.~Hamar and D.~von Harrach and F.H.~Heinsius and R.~Heitz and F.~Herrmann and N.~Horikawa and N.~d'Hose and C.-Y.~Hsieh and S.~Huber and S.~Ishimoto and A.~Ivanov and Yu.~Ivanshin and T.~Iwata and V.~Jary and R.~Joosten and P.~Joerg and E.~Kabuss and A.~Kerbizi and B.~Ketzer and G.V.~Khaustov and Yu.A.~Khokhlov and Yu.~Kisselev and F.~Klein and J.H.~Koivuniemi and V.N.~Kolosov and K.~Kondo and K.~Koenigsmann and I.~Konorov and V.F.~Konstantinov and A.M.~Kotzinian and O.M.~Kouznetsov and Z.~Kral and M.~Kraemer and P.~Kremser and F.~Krinner and Z.V.~Kroumchtein and Y.~Kulinich and F.~Kunne and K.~Kurek and R.P.~Kurjata and I.I.~Kuznetsov and A.~Kveton and A.A.~Lednev and E.A.~Levchenko and M.~Levillain and S.~Levorato and Y.-S.~Lian and J.~Lichtenstadt and R.~Longo and V.E.~Lyubovitskij and A.~Maggiora and A.~Magnon and N.~Makins and N.~Makke and G.K.~Mallot and S.A.~Mamon and B.~Marianski and A.~Martin and J.~Marzec and J.~Matousek and H.~Matsuda and T.~Matsuda and G.V.~Meshcheryakov and M.~Meyer and W.~Meyer and Yu.V.~Mikhailov and M.~Mikhasenko and E.~Mitrofanov and N.~Mitrofanov and Y.~Miyachi and A.~Nagaytsev and F.~Nerling and D.~Neyret and J.~Novy and W.-D.~Nowak and G.~Nukazuka and A.S.~Nunes and A.G.~Olshevsky and I.~Orlov and M.~Ostrick and D.~Panzieri and B.~Parsamyan and S.~Paul and J.-C.~Peng and F.~Pereira and M.~Pesek and M.~Peskova and D.V.~Peshekhonov and N.~Pierre and S.~Platchkov and J.~Pochodzalla and V.A.~Polyakov and J.~Pretz and M.~Quaresma and C.~Quintans and S.~Ramos and C.~Regali and G.~Reicherz and C.~Riedl and N.S.~Rogacheva and D.I.~Ryabchikov and A.~Rybnikov and A.~Rychter and R.~Salac and V.D.~Samoylenko and A.~Sandacz and C.~Santos and S.~Sarkar and I.A.~Savin and T.~Sawada and G.~Sbrizzai and P.~Schiavon and K.~Schmidt and H.~Schmieden and K.~Schoenning and E.~Seder and A.~Selyunin and L.~Silva and L.~Sinha and S.~Sirtl and M.~Slunecka and J.~Smolik and A.~Srnka and D.~Steffen and M.~Stolarski and O.~Subrt and M.~Sulc and H.~Suzuki and A.~Szabelski and T.~Szameitat and P.~Sznajder and M.~Tasevsky and S.~Tessaro and F.~Tessarotto and A.~Thiel and J.~Tomsa and F.~Tosello and V.~Tskhay and S.~Uhl and B.I.~Vasilishin and A.~Vauth and J.~Veloso and A.Vidon and M.~Virius and S.~Wallner and T.~Weisrock and M.~Wilfert and J.~ter Wolbeek and K.~Zaremba and P.~Zavada and M.~Zavertyaev and E.~Zemlyanichkina and N.~Zhuravlev and M.~Ziembicki}, title = {{S}earch for muoproduction of ${X}(3872)$ at {COMPASS} and indication of a new state $\widetilde{{X}}(3872)$}, year = {2017}, eprint = {1707.01796}, doi = {10.1016/j.physletb.2018.07.008}, note = {arXiv:1707.01796v2} }
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We have searched for exclusive production of exotic charmonia in the reaction $\mu^+~N \rightarrow \mu^+ (J\!/\!\psi\pi^+\pi^-)\pi^{\pm}~N'$ using COMPASS data collected with incoming muons of 160 GeV/$c$ and 200 GeV/$c$ momentum. In the $J\!/\!\psi\pi^+\pi^-$ mass distribution we observe a signal with a statistical significance of 4.1 $\sigma$. Its mass and width are consistent with those of the $X(3872)$. The shape of the $\pi^+\pi^-$ mass distribution from the observed decay into $J\!/\!\psi\pi^+\pi^-$ shows disagreement with previous observations for $X(3872)$. The observed signal may be interpreted as a possible evidence of a new charmonium state. It could be associated with a neutral partner of $X(3872)$ with $C = -1$ predicted by a tetraquark model. The product of cross section and branching fraction of the decay of the observed state into $J\!/\!\psi\pi^+\pi^-$ is determined to be 71$\pm$28(stat)$\pm$39(syst) pb.
First measurement of transverse-spin-dependent azimuthal asymmetries in the Drell-Yan process
Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badelek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, et al (200)
Apr 04 2017 hep-ex hep-ph arXiv:1704.00488v1

@misc{1704.00488, author = {Aghasyan and R.~Akhunzyanov and M.G.~Alexeev and G.D.~Alexeev and A.~Amoroso and V.~Andrieux and N.V.~Anfimov and V.~Anosov and A.~Antoshkin and K.~Augsten and W.~Augustyniak and A.~Austregesilo and C.D.R.~Azevedo and B.~Badelek and F.~Balestra and M.~Ball and J.~Barth and R.~Beck and Y.~Bedfer and J.~Bernhard and K.~Bicker and E.~R.~Bielert and R.~Birsa and M.~Bodlak and P.~Bordalo and F.~Bradamante and C.~Braun and A.~Bressan and M.~Buechele and W.-C.~Chang and C.~Chatterjee and M.~Chiosso and I.~Choi and S.-U.~Chung and A.~Cicuttin and M.L.~Crespo and S.~Dalla Torre and S.S.~Dasgupta and S.~Dasgupta and O.Yu.~Denisov and L.~Dhara and S.V.~Donskov and N.~Doshita and Ch.~Dreisbach and W.~Duennweber and M.~Dziewiecki and A.~Efremov and P.D.~Eversheim and M.~Faessler and A.~Ferrero and M.~Finger and M.~Finger jr.~and H.~Fischer and C.~Franco and N.~du Fresne von Hohenesche and J.M.~Friedrich and V.~Frolov and E.~Fuchey and F.~Gautheron and O.P.~Gavrichtchouk and S.~Gerassimov and J.~Giarra and F.~Giordano and I.~Gnesi and M.~Gorzellik and A.~Grasso and M.~Grosse Perdekamp and B.~Grube and T.~Grussenmeyer and A.~Guskov and D.~Hahne and G.~Hamar and D.~von Harrach and F.H.~Heinsius and R.~Heitz and F.~Herrmann and N.~Horikawa and N.~d'Hose and C.-Y.~Hsieh and S.~Huber and S.~Ishimoto and A.~Ivanov and Yu.~Ivanshin and T.~Iwata and V.~Jary and R.~Joosten and P.~Joerg and E.~Kabuss and A.~Kerbizi and B.~Ketzer and G.V.~Khaustov and Yu.A.~Khokhlov and Yu.~Kisselev and F.~Klein and J.H.~Koivuniemi and V.N.~Kolosov and K.~Kondo and K.~Koenigsmann and I.~Konorov and V.F.~Konstantinov and A.M.~Kotzinian and O.M.~Kouznetsov and Z.~Kral and M.~Kraemer and P.~Kremser and F.~Krinner and Z.V.~Kroumchtein and Y.~Kulinich and F.~Kunne and K.~Kurek and R.P.~Kurjata and A.~Kveton and A.A.~Lednev and M.~Levillain and S.~Levorato and Y.-S.~Lian and J.~Lichtenstadt and R.~Longo and A.~Maggiora and A.~Magnon and N.~Makins and N.~Makke and G.K.~Mallot and B.~Marianski and A.~Martin and J.~Marzec and J.~Matousek and H.~Matsuda and T.~Matsuda and G.V.~Meshcheryakov and M.~Meyer and W.~Meyer and Yu.V.~Mikhailov and M.~Mikhasenko and E.~Mitrofanov and N.~Mitrofanov and Y.~Miyachi and A.~Nagaytsev and F.~Nerling and D.~Neyret and J.~Novy and W.-D.~Nowak and G.~Nukazuka and A.S.~Nunes and A.G.~Olshevsky and I.~Orlov and M.~Ostrick and D.~Panzieri and B.~Parsamyan and S.~Paul and J.-C.~Peng and F.~Pereira and M.~Pesek and D.V.~Peshekhonov and N.~Pierre and S.~Platchkov and J.~Pochodzalla and V.A.~Polyakov and J.~Pretz and M.~Quaresma and C.~Quintans and S.~Ramos and C.~Regali and G.~Reicherz and C.~Riedl and N.S.~Rogacheva and M.~Roskot and D.I.~Ryabchikov and A.~Rybnikov and A.~Rychter and R.~Salac and V.D.~Samoylenko and A.~Sandacz and C.~Santos and S.~Sarkar and I.A.~Savin and T.~Sawada and G.~Sbrizzai and P.~Schiavon and K.~Schmidt and H.~Schmieden and K.~Schoenning and E.~Seder and A.~Selyunin and L.~Silva and L.~Sinha and S.~Sirtl and M.~Slunecka and J.~Smolik and A.~Srnka and D.~Steffen and M.~Stolarski and O.~Subrt and M.~Sulc and H.~Suzuki and A.~Szabelski and T.~Szameitat and P.~Sznajder and M.~Tasevsky and S.~Tessaro and F.~Tessarotto and A.~Thiel and J.~Tomsa and F.~Tosello and V.~Tskhay and S.~Uhl and A.~Vauth and J.~Veloso and M.~Virius and J.~Vondra and S.~Wallner and T.~Weisrock and M.~Wilfert and J.~ter Wolbeek and K.~Zaremba and P.~Zavada and M.~Zavertyaev and E.~Zemlyanichkina and N.~Zhuravlev and M.~Ziembicki}, title = {{F}irst measurement of transverse-spin-dependent azimuthal asymmetries in the {D}rell-{Y}an process}, year = {2017}, eprint = {1704.00488}, note = {arXiv:1704.00488v1} }
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The first measurement of transverse-spin-dependent azimuthal asymmetries in the pion-induced Drell-Yan (DY) process is reported. We use the CERN SPS 190 GeV/$c$, $\pi^{-}$ beam and a transversely polarized ammonia target. Three azimuthal asymmetries giving access to different transverse-momentum-dependent (TMD) parton distribution functions (PDFs) are extracted using dimuon events with invariant mass between 4.3 GeV/$c^2$ and 8.5 GeV/$c^2$. The observed sign of the Sivers asymmetry is found to be consistent with the fundamental prediction of Quantum Chromodynamics (QCD) that the Sivers TMD PDFs extracted from DY have a sign opposite to the one extracted from semi-inclusive deep-inelastic scattering (SIDIS) data. We present two other asymmetries originating from the pion Boer-Mulders TMD PDFs convoluted with either the nucleon transversity or pretzelosity TMD PDFs. These DY results are obtained at a hard scale comparable to that of a recent COMPASS SIDIS measurement and hence allow unique tests of fundamental QCD universality predictions.
First measurement of the Sivers asymmetry for gluons from SIDIS data
C. Adolph, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badelek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, et al (207)
Jan 11 2017 hep-ex hep-ph arXiv:1701.02453v1

@misc{1701.02453, author = {C.~Adolph and M.~Aghasyan and R.~Akhunzyanov and M.G.~Alexeev and G.D.~Alexeev and A.~Amoroso and V.~Andrieux and N.V.~Anfimov and V.~Anosov and A.~Antoshkin and K.~Augsten and W.~Augustyniak and A.~Austregesilo and C.D.R.~Azevedo and B.~Badelek and F.~Balestra and M.~Ball and J.~Barth and R.~Beck and Y.~Bedfer and J.~Bernhard and K.~Bicker and E.~R.~Bielert and R.~Birsa and M.~Bodlak and P.~Bordalo and F.~Bradamante and C.~Braun and A.~Bressan and M.~Buechele and W.-C.~Chang and C.~Chatterjee and M.~Chiosso and I.~Choi and S.-U.~Chung and A.~Cicuttin and M.L.~Crespo and Q.~Curiel and S.~Dalla Torre and S.S.~Dasgupta and S.~Dasgupta and O.Yu.~Denisov and L.~Dhara and S.V.~Donskov and N.~Doshita and Ch.~Dreisbach and V.~Duic and W.~Duennweber and M.~Dziewiecki and A.~Efremov and P.D.~Eversheim and W.~Eyrich and M.~Faessler and A.~Ferrero and M.~Finger and M.~Finger jr.~and H.~Fischer and C.~Franco and N.~du Fresne von Hohenesche and J.M.~Friedrich and V.~Frolov and E.~Fuchey and F.~Gautheron and O.P.~Gavrichtchouk and S.~Gerassimov and J.~Giarra and F.~Giordano and I.~Gnesi and M.~Gorzellik and S.~Grabmueller and A.~Grasso and M.~Grosse Perdekamp and B.~Grube and T.~Grussenmeyer and A.~Guskov and F.~Haas and D.~Hahne and G.~Hamar and D.~von Harrach and F.H.~Heinsius and R.~Heitz and F.~Herrmann and N.~Horikawa and N.~d'Hose and C.-Y.~Hsieh and S.~Huber and S.~Ishimoto and A.~Ivanov and Yu.~Ivanshin and T.~Iwata and V.~Jary and R.~Joosten and P.~Joerg and E.~Kabuss and A.~Kerbizi and B.~Ketzer and G.V.~Khaustov and Yu.A.~Khokhlov and Yu.~Kisselev and F.~Klein and K.~Klimaszewski and J.H.~Koivuniemi and V.N.~Kolosov and K.~Kondo and K.~Koenigsmann and I.~Konorov and V.F.~Konstantinov and A.M.~Kotzinian and O.M.~Kouznetsov and M.~Kraemer and P.~Kremser and F.~Krinner and Z.V.~Kroumchtein and Y.~Kulinich and F.~Kunne and K.~Kurek and R.P.~Kurjata and A.A.~Lednev and A.~Lehmann and M.~Levillain and S.~Levorato and Y.-S.~Lian and J.~Lichtenstadt and R.~Longo and A.~Maggiora and A.~Magnon and N.~Makins and N.~Makke and G.K.~Mallot and B.~Marianski and A.~Martin and J.~Marzec and J.~Matousek and H.~Matsuda and T.~Matsuda and G.V.~Meshcheryakov and M.~Meyer and W.~Meyer and Yu.V.~Mikhailov and M.~Mikhasenko and E.~Mitrofanov and N.~Mitrofanov and Y.~Miyachi and A.~Nagaytsev and F.~Nerling and D.~Neyret and J.~Novy and W.-D.~Nowak and G.~Nukazuka and A.S.~Nunes and A.G.~Olshevsky and I.~Orlov and M.~Ostrick and D.~Panzieri and B.~Parsamyan and S.~Paul and J.-C.~Peng and F.~Pereira and M.~Pesek and D.V.~Peshekhonov and N.~Pierre and S.~Platchkov and J.~Pochodzalla and V.A.~Polyakov and J.~Pretz and M.~Quaresma and C.~Quintans and S.~Ramos and C.~Regali and G.~Reicherz and C.~Riedl and N.S.~Rogacheva and M.~Roskot and D.I.~Ryabchikov and A.~Rybnikov and A.~Rychter and R.~Salac and V.D.~Samoylenko and A.~Sandacz and C.~Santos and S.~Sarkar and I.A.~Savin and T.~Sawada and G.~Sbrizzai and P.~Schiavon and K.~Schmidt and H.~Schmieden and K.~Schoenning and E.~Seder and A.~Selyunin and L.~Silva and L.~Sinha and S.~Sirtl and M.~Slunecka and J.~Smolik and A.~Srnka and D.~Steffen and M.~Stolarski and O.~Subrt and M.~Sulc and H.~Suzuki and A.~Szabelski and T.~Szameitat and P.~Sznajder and S.~Takekawa and M.~Tasevsky and S.~Tessaro and F.~Tessarotto and F.~Thibaud and A.~Thiel and F.~Tosello and V.~Tskhay and S.~Uhl and J.~Veloso and M.~Virius and J.~Vondra and S.~Wallner and T.~Weisrock and M.~Wilfert and J.~ter Wolbeek and K.~Zaremba and P.~Zavada and M.~Zavertyaev and E.~Zemlyanichkina and N.~Zhuravlev and M.~Ziembicki and A.~Zink}, title = {{F}irst measurement of the {S}ivers asymmetry for gluons from {SIDIS} data}, year = {2017}, eprint = {1701.02453}, note = {arXiv:1701.02453v1} }
PDF
The Sivers function describes the correlation between the transverse spin of a nucleon and the transverse motion of its partons. It was extracted from measurements of the azimuthal asymmetry of hadrons produced in semi-inclusive deep inelastic scattering of leptons off transversely polarised nucleon targets, and it turned out to be non-zero for quarks. In this letter the evaluation of the Sivers asymmetry for gluons in the same process is presented. The analysis method is based on a Monte Carlo simulation that includes three hard processes: photon-gluon fusion, QCD Compton scattering and leading-order virtual-photon absorption process. The Sivers asymmetries of the three processes are simultaneously extracted using the LEPTO event generator and a neural network approach. The method is applied to samples of events containing at least two hadrons with large transverse momentum from the COMPASS data taken with a 160 GeV/$c$ muon beam scattered off transversely polarised deuterons and protons. With a significance of more than two standard deviations a negative value is obtained for the gluon Sivers asymmetry. The result of a similar analysis for a Collins-like asymmetry for gluons is consistent with zero.
Final COMPASS results on the deuteron spin-dependent structure function $g_1^{\rm d}$ and the Bjorken sum rule
C. Adolph, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badelek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, et al (207)
Dec 05 2016 hep-ex arXiv:1612.00620v1

@misc{1612.00620, author = {C.~Adolph and M.~Aghasyan and R.~Akhunzyanov and M.G.~Alexeev and G.D.~Alexeev and A.~Amoroso and V.~Andrieux and N.V.~Anfimov and V.~Anosov and K.~Augsten and W.~Augustyniak and A.~Austregesilo and C.D.R.~Azevedo and B.~Badelek and F.~Balestra and M.~Ball and J.~Barth and R.~Beck and Y.~Bedfer and J.~Bernhard and K.~Bicker and E.~R.~Bielert and R.~Birsa and M.~Bodlak and P.~Bordalo and F.~Bradamante and C.~Braun and A.~Bressan and M.~Buechele and W.-C.~Chang and C.~Chatterjee and M.~Chiosso and I.~Choi and S.-U.~Chung and A.~Cicuttin and M.L.~Crespo and Q.~Curiel and S.~Dalla Torre and S.S.~Dasgupta and S.~Dasgupta and O.Yu.~Denisov and L.~Dhara and S.V.~Donskov and N.~Doshita and Ch.~Dreisbach and V.~Duic and W.~Duennweber and M.~Dziewiecki and A.~Efremov and P.D.~Eversheim and W.~Eyrich and M.~Faessler and A.~Ferrero and M.~Finger and M.~Finger jr.~and H.~Fischer and C.~Franco and N.~du Fresne von Hohenesche and J.M.~Friedrich and V.~Frolov and E.~Fuchey and F.~Gautheron and O.P.~Gavrichtchouk and S.~Gerassimov and J.~Giarra and F.~Giordano and I.~Gnesi and M.~Gorzellik and S.~Grabmueller and A.~Grasso and M.~Grosse Perdekamp and B.~Grube and T.~Grussenmeyer and A.~Guskov and F.~Haas and D.~Hahne and G.~Hamar and D.~von Harrach and F.H.~Heinsius and R.~Heitz and F.~Herrmann and N.~Horikawa and N.~d'Hose and C.-Y.~Hsieh and S.~Huber and S.~Ishimoto and A.~Ivanov and Yu.~Ivanshin and T.~Iwata and V.~Jary and R.~Joosten and P.~Joerg and E.~Kabuss and A.~Kerbizi and B.~Ketzer and G.V.~Khaustov and Yu.A.~Khokhlov and Yu.~Kisselev and F.~Klein and K.~Klimaszewski and J.H.~Koivuniemi and V.N.~Kolosov and K.~Kondo and K.~Koenigsmann and I.~Konorov and V.F.~Konstantinov and A.M.~Kotzinian and O.M.~Kouznetsov and M.~Kraemer and P.~Kremser and F.~Krinner and Z.V.~Kroumchtein and Y.~Kulinich and F.~Kunne and K.~Kurek and R.P.~Kurjata and A.A.~Lednev and A.~Lehmann and M.~Levillain and S.~Levorato and Y.-S.~Lian and J.~Lichtenstadt and R.~Longo and A.~Maggiora and A.~Magnon and N.~Makins and N.~Makke and G.K.~Mallot and B.~Marianski and A.~Martin and J.~Marzec and J.~Matousek and H.~Matsuda and T.~Matsuda and G.V.~Meshcheryakov and M.~Meyer and W.~Meyer and Yu.V.~Mikhailov and M.~Mikhasenko and E.~Mitrofanov and N.~Mitrofanov and Y.~Miyachi and A.~Nagaytsev and F.~Nerling and D.~Neyret and J.~Novy and W.-D.~Nowak and G.~Nukazuka and A.S.~Nunes and A.G.~Olshevsky and I.~Orlov and M.~Ostrick and D.~Panzieri and B.~Parsamyan and S.~Paul and J.-C.~Peng and F.~Pereira and M.~Pesek and D.V.~Peshekhonov and N.~Pierre and S.~Platchkov and J.~Pochodzalla and V.A.~Polyakov and J.~Pretz and M.~Quaresma and C.~Quintans and S.~Ramos and C.~Regali and G.~Reicherz and C.~Riedl and M.~Roskot and N.S.~Rossiyskaya and D.I.~Ryabchikov and A.~Rybnikov and A.~Rychter and R.~Salac and V.D.~Samoylenko and A.~Sandacz and C.~Santos and S.~Sarkar and I.A.~Savin and T.~Sawada and G.~Sbrizzai and P.~Schiavon and K.~Schmidt and H.~Schmieden and K.~Schoenning and E.~Seder and A.~Selyunin and L.~Silva and L.~Sinha and S.~Sirtl and M.~Slunecka and J.~Smolik and A.~Srnka and D.~Steffen and M.~Stolarski and O.~Subrt and M.~Sulc and H.~Suzuki and A.~Szabelski and T.~Szameitat and P.~Sznajder and S.~Takekawa and M.~Tasevsky and S.~Tessaro and F.~Tessarotto and F.~Thibaud and A.~Thiel and F.~Tosello and V.~Tskhay and S.~Uhl and J.~Veloso and M.~Virius and J.~Vondra and S.~Wallner and T.~Weisrock and M.~Wilfert and R.~Windmolders and J.~ter Wolbeek and K.~Zaremba and P.~Zavada and M.~Zavertyaev and E.~Zemlyanichkina and N.~Zhuravlev and M.~Ziembicki and A.~Zink}, title = {{F}inal {COMPASS} results on the deuteron spin-dependent structure function $g_1^{\rm d}$ and the {B}jorken sum rule}, year = {2016}, eprint = {1612.00620}, note = {arXiv:1612.00620v1} }
PDF
Final results are presented from the inclusive measurement of deep-inelastic polarised-muon scattering on longitudinally polarised deuterons using a $^6$LiD target. The data were taken at $160~{\rm GeV}$ beam energy and the results are shown for the kinematic range $1~({\rm GeV}/c)^2 < Q^2 < 100~({\rm GeV}/c)^2$ in photon virtuality, $0.004<x<0.7$ in the Bjorken scaling variable and $W > 4~{\rm GeV}/c^2$ in the mass of the hadronic final state. The deuteron double-spin asymmetry $A_1^{\rm d}$ and the deuteron longitudinal-spin structure function $g_1^{\rm d}$ are presented in bins of $x$ and $Q^2$. Towards lowest accessible values of $x$, $g_1^{\rm d}$ decreases and becomes consistent with zero within uncertainties. The presented final $g_1^{\rm d}$ values together with the recently published final $g_1^{\rm p}$ values of COMPASS are used to again evaluate the Bjorken sum rule and perform the QCD fit to the $g_1$ world data at next-to-leading order of the strong coupling constant. In both cases, changes in central values of the resulting numbers are well within statistical uncertainties. The flavour-singlet axial charge $a_0$, which is identified in the $\overline{\rm MS}$ renormalisation scheme with the total contribution of quark helicities to the nucleon spin, is extracted from only the COMPASS deuteron data with negligible extrapolation uncertainty: $a_0 (Q^2 = 3~({\rm GeV}/c)^2) = 0.32 \pm 0.02_{\rm stat} \pm0.04_{\rm syst} \pm 0.05_{\rm evol}$. Together with the recent results on the proton spin structure function $g_1^{\rm p}$, the results on $g_1^{\rm d}$ constitute the COMPASS legacy on the measurements of $g_1$ through inclusive spin-dependent deep inelastic scattering.
Sivers asymmetry extracted in SIDIS at the hard scale of the Drell-Yan process at COMPASS
C. Adolph, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badelek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, et al (207)
Sep 26 2016 hep-ex hep-ph arXiv:1609.07374v2

@misc{1609.07374, author = {C.~Adolph and M.~Aghasyan and R.~Akhunzyanov and M.G.~Alexeev and G.D.~Alexeev and A.~Amoroso and V.~Andrieux and N.V.~Anfimov and V.~Anosov and K.~Augsten and W.~Augustyniak and A.~Austregesilo and C.D.R.~Azevedo and B.~Badelek and F.~Balestra and M.~Ball and J.~Barth and R.~Beck and Y.~Bedfer and J.~Bernhard and K.~Bicker and E.~R.~Bielert and R.~Birsa and M.~Bodlak and P.~Bordalo and F.~Bradamante and C.~Braun and A.~Bressan and M.~Buechele and W.-C.~Chang and C.~Chatterjee and M.~Chiosso and I.~Choi and S.-U.~Chung and A.~Cicuttin and M.L.~Crespo and Q.~Curiel and S.~Dalla Torre and S.S.~Dasgupta and S.~Dasgupta and O.Yu.~Denisov and L.~Dhara and S.V.~Donskov and N.~Doshita and Ch.~Dreisbach and V.~Duic and W.~Duennweber and M.~Dziewiecki and A.~Efremov and C.~Elia and P.D.~Eversheim and W.~Eyrich and M.~Faessler and A.~Ferrero and M.~Finger and M.~Finger jr.~and H.~Fischer and C.~Franco and N.~du Fresne von Hohenesche and J.M.~Friedrich and V.~Frolov and E.~Fuchey and F.~Gautheron and O.P.~Gavrichtchouk and S.~Gerassimov and J.~Giarra and F.~Giordano and I.~Gnesi and M.~Gorzellik and S.~Grabmueller and A.~Grasso and M.~Grosse Perdekamp and B.~Grube and T.~Grussenmeyer and A.~Guskov and F.~Haas and D.~Hahne and G.~Hamar and D.~von Harrach and F.H.~Heinsius and R.~Heitz and F.~Herrmann and N.~Horikawa and N.~d'Hose and C.-Y.~Hsieh and S.~Huber and S.~Ishimoto and A.~Ivanov and Yu.~Ivanshin and T.~Iwata and V.~Jary and R.~Joosten and P.~Joerg and E.~Kabuss and B.~Ketzer and G.V.~Khaustov and Yu.A.~Khokhlov and Yu.~Kisselev and F.~Klein and K.~Klimaszewski and J.H.~Koivuniemi and V.N.~Kolosov and K.~Kondo and K.~Koenigsmann and I.~Konorov and V.F.~Konstantinov and A.M.~Kotzinian and O.M.~Kouznetsov and M.~Kraemer and P.~Kremser and F.~Krinner and Z.V.~Kroumchtein and Y.~Kulinich and F.~Kunne and K.~Kurek and R.P.~Kurjata and A.A.~Lednev and A.~Lehmann and M.~Levillain and S.~Levorato and Y.-S.~Lian and J.~Lichtenstadt and R.~Longo and A.~Maggiora and A.~Magnon and N.~Makins and N.~Makke and G.K.~Mallot and B.~Marianski and A.~Martin and J.~Marzec and J.~Matousek and H.~Matsuda and T.~Matsuda and G.V.~Meshcheryakov and M.~Meyer and W.~Meyer and Yu.V.~Mikhailov and M.~Mikhasenko and E.~Mitrofanov and N.~Mitrofanov and Y.~Miyachi and A.~Nagaytsev and F.~Nerling and D.~Neyret and J.~Novy and W.-D.~Nowak and G.~Nukazuka and A.S.~Nunes and A.G.~Olshevsky and I.~Orlov and M.~Ostrick and D.~Panzieri and B.~Parsamyan and S.~Paul and J.-C.~Peng and F.~Pereira and M.~Pesek and D.V.~Peshekhonov and N.~Pierre and S.~Platchkov and J.~Pochodzalla and V.A.~Polyakov and J.~Pretz and M.~Quaresma and C.~Quintans and S.~Ramos and C.~Regali and G.~Reicherz and C.~Riedl and M.~Roskot and N.S.~Rossiyskaya and D.I.~Ryabchikov and A.~Rybnikov and A.~Rychter and R.~Salac and V.D.~Samoylenko and A.~Sandacz and C.~Santos and S.~Sarkar and I.A.~Savin and T.~Sawada and G.~Sbrizzai and P.~Schiavon and K.~Schmidt and H.~Schmieden and K.~Schoenning and E.~Seder and A.~Selyunin and L.~Silva and L.~Sinha and S.~Sirtl and M.~Slunecka and J.~Smolik and F.~Sozzi and A.~Srnka and D.~Steffen and M.~Stolarski and O.~Subrt and M.~Sulc and H.~Suzuki and A.~Szabelski and T.~Szameitat and P.~Sznajder and S.~Takekawa and M.~Tasevsky and S.~Tessaro and F.~Tessarotto and F.~Thibaud and A.~Thiel and F.~Tosello and V.~Tskhay and S.~Uhl and J.~Veloso and M.~Virius and J.~Vondra and S.~Wallner and T.~Weisrock and M.~Wilfert and J.~ter Wolbeek and K.~Zaremba and P.~Zavada and M.~Zavertyaev and E.~Zemlyanichkina and N.~Zhuravlev and M.~Ziembicki and A.~Zink}, title = {{S}ivers asymmetry extracted in {SIDIS} at the hard scale of the {D}rell-{Y}an process at {COMPASS}}, year = {2016}, eprint = {1609.07374}, doi = {10.1016/j.physletb.2017.04.042}, note = {arXiv:1609.07374v2} }
PDF
Proton transverse-spin azimuthal asymmetries are extracted from the COMPASS 2010 semi-inclusive hadron measurements in deep inelastic muon-nucleon scattering in those four regions of the photon virtuality $Q^2$, which correspond to the four regions of the di-muon mass $\sqrt{Q^2}$ used in the ongoing analysis of the COMPASS Drell-Yan measurements. This allows for a future direct comparison of the nucleon transverse-momentum-dependent parton distribution functions extracted from these two alternative measurements. Various two-dimensional kinematic dependences are presented for the azimuthal asymmetries induced by the Sivers transverse-momentum-dependent parton distribution function. The integrated Sivers asymmetries are found to be positive with an accuracy that appears to be sufficient to test the sign change of the Sivers function predicted by Quantum Chromodynamics.
Azimuthal asymmetries of charged hadrons produced in high-energy muon scattering off longitudinally polarised deuterons
C. Adolph, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badelek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, et al (205)
Sep 21 2016 hep-ex hep-ph arXiv:1609.06062v2

@misc{1609.06062, author = {C.~Adolph and M.~Aghasyan and R.~Akhunzyanov and M.G.~Alexeev and G.D.~Alexeev and A.~Amoroso and V.~Andrieux and N.V.~Anfimov and V.~Anosov and K.~Augsten and W.~Augustyniak and A.~Austregesilo and C.D.R.~Azevedo and B.~Badelek and F.~Balestra and M.~Ball and J.~Barth and R.~Beck and Y.~Bedfer and J.~Bernhard and K.~Bicker and E.~R.~Bielert and R.~Birsa and M.~Bodlak and P.~Bordalo and F.~Bradamante and C.~Braun and A.~Bressan and M.~Buechele and W.-C.~Chang and C.~Chatterjee and M.~Chiosso and I.~Choi and S.-U.~Chung and A.~Cicuttin and M.L.~Crespo and Q.~Curiel and S.~Dalla Torre and S.S.~Dasgupta and S.~Dasgupta and O.Yu.~Denisov and L.~Dhara and S.V.~Donskov and N.~Doshita and Ch.~Dreisbach and V.~Duic and W.~Duennweber and M.~Dziewiecki and A.~Efremov and P.D.~Eversheim and W.~Eyrich and M.~Faessler and A.~Ferrero and M.~Finger and M.~Finger jr.~and H.~Fischer and C.~Franco and N.~du Fresne von Hohenesche and J.M.~Friedrich and V.~Frolov and E.~Fuchey and F.~Gautheron and O.P.~Gavrichtchouk and S.~Gerassimov and J.~Giarra and F.~Giordano and I.~Gnesi and M.~Gorzellik and S.~Grabmueller and A.~Grasso and M.~Grosse Perdekamp and B.~Grube and T.~Grussenmeyer and A.~Guskov and F.~Haas and D.~Hahne and G.~Hamar and D.~von Harrach and F.H.~Heinsius and R.~Heitz and F.~Herrmann and N.~Horikawa and N.~d'Hose and C.-Y.~Hsieh and S.~Huber and S.~Ishimoto and A.~Ivanov and Yu.~Ivanshin and T.~Iwata and V.~Jary and R.~Joosten and P.~Joerg and E.~Kabuss and B.~Ketzer and G.V.~Khaustov and Yu.A.~Khokhlov and Yu.~Kisselev and F.~Klein and K.~Klimaszewski and J.H.~Koivuniemi and V.N.~Kolosov and K.~Kondo and K.~Koenigsmann and I.~Konorov and V.F.~Konstantinov and A.M.~Kotzinian and O.M.~Kouznetsov and M.~Kraemer and P.~Kremser and F.~Krinner and Z.V.~Kroumchtein and Y.~Kulinich and F.~Kunne and K.~Kurek and R.P.~Kurjata and A.A.~Lednev and A.~Lehmann and M.~Levillain and S.~Levorato and Y.-S.~Lian and J.~Lichtenstadt and R.~Longo and A.~Maggiora and A.~Magnon and N.~Makins and N.~Makke and G.K.~Mallot and B.~Marianski and A.~Martin and J.~Marzec and J.~Matousek and H.~Matsuda and T.~Matsuda and G.V.~Meshcheryakov and M.~Meyer and W.~Meyer and Yu.V.~Mikhailov and M.~Mikhasenko and E.~Mitrofanov and N.~Mitrofanov and Y.~Miyachi and A.~Nagaytsev and F.~Nerling and D.~Neyret and J.~Novy and W.-D.~Nowak and G.~Nukazuka and A.S.~Nunes and A.G.~Olshevsky and I.~Orlov and M.~Ostrick and D.~Panzieri and B.~Parsamyan and S.~Paul and J.-C.~Peng and F.~Pereira and M.~Pesek and D.V.~Peshekhonov and N.~Pierre and S.~Platchkov and J.~Pochodzalla and V.A.~Polyakov and J.~Pretz and M.~Quaresma and C.~Quintans and S.~Ramos and C.~Regali and G.~Reicherz and C.~Riedl and M.~Roskot and N.S.~Rossiyskaya and D.I.~Ryabchikov and A.~Rybnikov and A.~Rychter and R.~Salac and V.D.~Samoylenko and A.~Sandacz and C.~Santos and S.~Sarkar and I.A.~Savin and T.~Sawada and G.~Sbrizzai and P.~Schiavon and K.~Schmidt and H.~Schmieden and K.~Schoenning and E.~Seder and A.~Selyunin and L.~Silva and L.~Sinha and S.~Sirtl and M.~Slunecka and J.~Smolik and A.~Srnka and D.~Steffen and M.~Stolarski and O.~Subrt and M.~Sulc and H.~Suzuki and A.~Szabelski and T.~Szameitat and P.~Sznajder and S.~Takekawa and M.~Tasevsky and S.~Tessaro and F.~Tessarotto and F.~Thibaud and A.~Thiel and F.~Tosello and V.~Tskhay and S.~Uhl and J.~Veloso and M.~Virius and J.~Vondra and S.~Wallner and T.~Weisrock and M.~Wilfert and J.~ter Wolbeek and K.~Zaremba and P.~Zavada and M.~Zavertyaev and E.~Zemlyanichkina and N.~Zhuravlev and M.~Ziembicki and A.~Zink}, title = {{A}zimuthal asymmetries of charged hadrons produced in high-energy muon scattering off longitudinally polarised deuterons}, year = {2016}, eprint = {1609.06062}, note = {arXiv:1609.06062v2} }
PDF
Single hadron azimuthal asymmetries of positive and negative hadrons produced in muon semi-inclusive deep inelastic scattering off longitudinally polarised deuterons are determined using the 2006 COMPASS data and also combined all deuteron COMPASS data. For each hadron charge, the dependence of the azimuthal asymmetry on the hadron azimuthal angle $\phi$ is obtained by means of a five-parameter fitting function that besides a $\phi$-independent term includes four modulations predicted by theory: $\sin\phi$, $\sin 2 \phi$, $\sin 3\phi$ and $\cos\phi$. The amplitudes of the five terms have been extracted, first, for the hadrons in the whole available kinematic region. In further fits, performed for hadrons from a restricted kinematic region, the $\phi$-dependence is determined as a function of one of three variables (Bjorken-$x$, fractional energy of virtual photon taken by the outgoing hadron and hadron transverse momentum), while disregarding the others. Except the $\phi$-independent term, all the modulation amplitudes are very small, and no clear kinematic dependence could be observed within experimental uncertainties.
Multiplicities of charged kaons from deep-inelastic muon scattering off an isoscalar target
C. Adolph, J. Agarwala, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badelek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, et al (207)
Aug 25 2016 hep-ex nucl-ex arXiv:1608.06760v1

@misc{1608.06760, author = {C.~Adolph and J.~Agarwala and M.~Aghasyan and R.~Akhunzyanov and M.G.~Alexeev and G.D.~Alexeev and A.~Amoroso and V.~Andrieux and N.V.~Anfimov and V.~Anosov and K.~Augsten and W.~Augustyniak and A.~Austregesilo and C.D.R.~Azevedo and B.~Badelek and F.~Balestra and M.~Ball and J.~Barth and R.~Beck and Y.~Bedfer and J.~Bernhard and K.~Bicker and E.~R.~Bielert and R.~Birsa and M.~Bodlak and P.~Bordalo and F.~Bradamante and C.~Braun and A.~Bressan and M.~Buechele and L.~Capozza and W.-C.~Chang and C.~Chatterjee and M.~Chiosso and I.~Choi and S.-U.~Chung and A.~Cicuttin and M.L.~Crespo and Q.~Curiel and S.~Dalla Torre and S.S.~Dasgupta and S.~Dasgupta and O.Yu.~Denisov and L.~Dhara and S.V.~Donskov and N.~Doshita and Ch.~Dreisbach and V.~Duic and W.~Duennweber and M.~Dziewiecki and A.~Efremov and P.D.~Eversheim and W.~Eyrich and M.~Faessler and A.~Ferrero and M.~Finger and M.~Finger jr.~and H.~Fischer and C.~Franco and N.~du Fresne von Hohenesche and J.M.~Friedrich and V.~Frolov and E.~Fuchey and F.~Gautheron and O.P.~Gavrichtchouk and S.~Gerassimov and F.~Giordano and I.~Gnesi and M.~Gorzellik and S.~Grabmueller and A.~Grasso and M.~Grosse Perdekamp and B.~Grube and T.~Grussenmeyer and A.~Guskov and F.~Haas and D.~Hahne and G.~Hamar and D.~von Harrach and F.H.~Heinsius and R.~Heitz and F.~Herrmann and N.~Horikawa and N.~d'Hose and C.-Y.~Hsieh and S.~Huber and S.~Ishimoto and A.~Ivanov and Yu.~Ivanshin and T.~Iwata and V.~Jary and R.~Joosten and P.~Joeorg and E.~Kabuss and B.~Ketzer and G.V.~Khaustov and Yu.A.~Khokhlov and Yu.~Kisselev and F.~Klein and K.~Klimaszewski and J.H.~Koivuniemi and V.N.~Kolosov and K.~Kondo and K.~Koenigsmann and I.~Konorov and V.F.~Konstantinov and A.M.~Kotzinian and O.M.~Kouznetsov and M.~Kraemer and P.~Kremser and F.~Krinner and Z.V.~Kroumchtein and Y.~Kulinich and F.~Kunne and K.~Kurek and R.P.~Kurjata and A.A.~Lednev and A.~Lehmann and M.~Levillain and S.~Levorato and Y.-S.~Lian and J.~Lichtenstadt and R.~Longo and A.~Maggiora and A.~Magnon and N.~Makins and N.~Makke and G.K.~Mallot and B.~Marianski and A.~Martin and J.~Marzec and J.~Matousek and H.~Matsuda and T.~Matsuda and G.V.~Meshcheryakov and M.~Meyer and W.~Meyer and Yu.V.~Mikhailov and M.~Mikhasenko and E.~Mitrofanov and N.~Mitrofanov and Y.~Miyachi and A.~Nagaytsev and F.~Nerling and D.~Neyret and J.~Novy and W.-D.~Nowak and G.~Nukazuka and A.S.~Nunes and A.G.~Olshevsky and I.~Orlov and M.~Ostrick and D.~Panzieri and B.~Parsamyan and S.~Paul and J.-C.~Peng and F.~Pereira and M.~Pesek and D.V.~Peshekhonov and N.~Pierre and S.~Platchkov and J.~Pochodzalla and V.A.~Polyakov and J.~Pretz and M.~Quaresma and C.~Quintans and S.~Ramos and C.~Regali and G.~Reicherz and C.~Riedl and M.~Roskot and N.S.~Rossiyskaya and D.I.~Ryabchikov and A.~Rybnikov and A.~Rychter and R.~Salac and V.D.~Samoylenko and A.~Sandacz and C.~Santos and S.~Sarkar and I.A.~Savin and T.~Sawada and G.~Sbrizzai and P.~Schiavon and K.~Schmidt and H.~Schmieden and K.~Schoenning and E.~Seder and A.~Selyunin and L.~Silva and L.~Sinha and S.~Sirtl and M.~Slunecka and J.~Smolik and A.~Srnka and D.~Steffen and M.~Stolarski and O.~Subrt and M.~Sulc and H.~Suzuki and A.~Szabelski and T.~Szameitat and P.~Sznajder and S.~Takekawa and M.~Tasevsky and S.~Tessaro and F.~Tessarotto and F.~Thibaud and A.~Thiel and F.~Tosello and V.~Tskhay and S.~Uhl and J.~Veloso and M.~Virius and J.~Vondra and S.~Wallner and T.~Weisrock and M.~Wilfert and R.~Windmolders and J.~ter Wolbeek and K.~Zaremba and P.~Zavada and M.~Zavertyaev and E.~Zemlyanichkina and N.~Zhuravlev and M.~Ziembicki and A.~Zink}, title = {{M}ultiplicities of charged kaons from deep-inelastic muon scattering off an isoscalar target}, year = {2016}, eprint = {1608.06760}, note = {arXiv:1608.06760v1} }
PDF
Precise measurements of charged-kaon multiplicities in deep inelastic scattering were performed. The results are presented in three-dimensional bins of the Bjorken scaling variable x, the relative virtual-photon energy y, and the fraction z of the virtual-photon energy carried by the produced hadron. The data were obtained by the COMPASS Collaboration by scattering 160 GeV muons off an isoscalar 6 LiD target. They cover the kinematic domain 1 (GeV/c)2 < Q2 < 60 (GeV/c)^2 in the photon virtuality, 0.004 < x < 0.4, 0.1 < y < 0.7, 0.20 < z < 0.85, and W > 5 GeV/c^2 in the invariant mass of the hadronic system. The results from the sum of the z-integrated K+ and K- multiplicities at high x point to a value of the non-strange quark fragmentation function larger than obtained by the earlier DSS fit.
Exclusive $\omega$ meson muoproduction on transversely polarised protons
C. Adolph, J. Agarwala, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badelek, F. Balestra, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, et al (209)
Jun 14 2016 hep-ex nucl-ex arXiv:1606.03725v2

@misc{1606.03725, author = {C.~Adolph and J.~Agarwala and M.~Aghasyan and R.~Akhunzyanov and M.G.~Alexeev and G.D.~Alexeev and A.~Amoroso and V.~Andrieux and N.V.~Anfimov and V.~Anosov and W.~Augustyniak and A.~Austregesilo and C.D.R.~Azevedo and B.~Badelek and F.~Balestra and J.~Barth and R.~Beck and Y.~Bedfer and J.~Bernhard and K.~Bicker and E.~R.~Bielert and R.~Birsa and J.~Bisplinghoff and M.~Bodlak and M.~Boer and P.~Bordalo and F.~Bradamante and C.~Braun and A.~Bressan and M.~Buechele and W.-C.~Chang and C.~Chatterjee and M.~Chiosso and I.~Choi and S.-U.~Chung and A.~Cicuttin and M.L.~Crespo and Q.~Curiel and S.~Dalla Torre and S.S.~Dasgupta and S.~Dasgupta and O.Yu.~Denisov and L.~Dhara and S.V.~Donskov and N.~Doshita and V.~Duic and W.~Duennweber and M.~Dziewiecki and A.~Efremov and P.D.~Eversheim and W.~Eyrich and M.~Faessler and A.~Ferrero and M.~Finger and M.~Finger jr.~and H.~Fischer and C.~Franco and N.~du Fresne von Hohenesche and J.M.~Friedrich and V.~Frolov and E.~Fuchey and F.~Gautheron and O.P.~Gavrichtchouk and S.~Gerassimov and F.~Giordano and I.~Gnesi and M.~Gorzellik and S.~Grabmueller and A.~Grasso and M.~Grosse Perdekamp and B.~Grube and T.~Grussenmeyer and A.~Guskov and F.~Haas and D.~Hahne and D.~von Harrach and R.~Hashimoto and F.H.~Heinsius and R.~Heitz and F.~Herrmann and F.~Hinterberger and N.~Horikawa and N.~dHose and C.-Y.~Hsieh and S.~Huber and S.~Ishimoto and A.~Ivanov and Yu.~Ivanshin and T.~Iwata and R.~Jahn and V.~Jary and R.~Joosten and P.~Joerg and E.~Kabuss and B.~Ketzer and G.V.~Khaustov and Yu.A.~Khokhlov and Yu.~Kisselev and F.~Klein and K.~Klimaszewski and J.H.~Koivuniemi and V.N.~Kolosov and K.~Kondo and K.~Koenigsmann and I.~Konorov and V.F.~Konstantinov and A.M.~Kotzinian and O.M.~Kouznetsov and M.~Kraemer and P.~Kremser and F.~Krinner and Z.V.~Kroumchtein and Y.~Kulinich and F.~Kunne and K.~Kurek and R.P.~Kurjata and A.A.~Lednev and A.~Lehmann and M.~Levillain and S.~Levorato and Y.-S.~Lian and J.~Lichtenstadt and R.~Longo and A.~Maggiora and A.~Magnon and N.~Makins and N.~Makke and G.K.~Mallot and C.~Marchand and B.~Marianski and A.~Martin and J.~Marzec and J.~Matousek and H.~Matsuda and T.~Matsuda and G.V.~Meshcheryakov and M.~Meyer and W.~Meyer and T.~Michigami and Yu.V.~Mikhailov and M.~Mikhasenko and E.~Mitrofanov and N.~Mitrofanov and Y.~Miyachi and P.~Montuenga and A.~Nagaytsev and F.~Nerling and D.~Neyret and V.I.~Nikolaenko and J.~Novy and W.-D.~Nowak and G.~Nukazuka and A.S.~Nunes and A.G.~Olshevsky and I.~Orlov and M.~Ostrick and D.~Panzieri and B.~Parsamyan and S.~Paul and J.-C.~Peng and F.~Pereira and M.~Pesek and D.V.~Peshekhonov and N.~Pierre and S.~Platchkov and J.~Pochodzalla and V.A.~Polyakov and J.~Pretz and M.~Quaresma and C.~Quintans and S.~Ramos and C.~Regali and G.~Reicherz and C.~Riedl and M.~Roskot and D.I.~Ryabchikov and A.~Rybnikov and A.~Rychter and R.~Salac and V.D.~Samoylenko and A.~Sandacz and C.~Santos and S.~Sarkar and I.A.~Savin and T.~Sawada and G.~Sbrizzai and P.~Schiavon and K.~Schmidt and H.~Schmieden and K.~Schoenning and S.~Schopferer and E.~Seder and A.~Selyunin and O.Yu.~Shevchenko and L.~Silva and L.~Sinha and S.~Sirtl and M.~Slunecka and J.~Smolik and F.~Sozzi and A.~Srnka and D.~Steffen and M.~Stolarski and M.~Sulc and H.~Suzuki and A.~Szabelski and T.~Szameitat and P.~Sznajder and S.~Takekawa and M.~Tasevsky and S.~Tessaro and F.~Tessarotto and F.~Thibaud and F.~Tosello and V.~Tskhay and S.~Uhl and J.~Veloso and M.~Virius and J.~Vondra and S.~Wallner and T.~Weisrock and M.~Wilfert and J.~ter Wolbeek and K.~Zaremba and P.~Zavada and M.~Zavertyaev and E.~Zemlyanichkina and M.~Ziembicki and A.~Zink}, title = {{E}xclusive $\omega$ meson muoproduction on transversely polarised protons}, year = {2016}, eprint = {1606.03725}, doi = {10.1016/j.nuclphysb.2016.12.015}, note = {arXiv:1606.03725v2} }
PDF
Exclusive production of $\omega$ mesons was studied at the COMPASS experiment by scattering $160~\mathrm{GeV}/\mathit{c}$ muons off transversely polarised protons. Five single-spin and three double-spin azimuthal asymmetries were measured in the range of photon virtuality $1~(\mathrm{GeV}/\mathit{c})^2 < Q^2 < 10~(\mathrm{GeV}/\mathit{c})^2$, Bjorken scaling variable $0.003 < x_{\mathit{Bj}} < 0.3$ and transverse momentum squared of the $\omega$ meson $0.05~(\mathrm{GeV}/\mathit{c})^2 < p_{T}^{2} < 0.5~(\mathrm{GeV}/\mathit{c})^2$. The measured asymmetries are sensitive to the nucleon helicity-flip Generalised Parton Distributions (GPD) $E$ that are related to the orbital angular momentum of quarks, the chiral-odd GPDs $H_{T}$ that are related to the transversity Parton Distribution Functions, and the sign of the $\pi\omega$ transition form factor. The results are compared to recent calculations of a GPD-based model.
Multiplicities of charged pions and unidentified charged hadrons from deep-inelastic scattering of muons off an isoscalar target
C. Adolph, J. Agarwala, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badelek, F. Balestra, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, et al (208)
Apr 12 2016 hep-ex nucl-ex arXiv:1604.02695v2

@misc{1604.02695, author = {C.~Adolph and J.~Agarwala and M.~Aghasyan and R.~Akhunzyanov and M.G.~Alexeev and G.D.~Alexeev and A.~Amoroso and V.~Andrieux and N.V.~Anfimov and V.~Anosov and W.~Augustyniak and A.~Austregesilo and C.D.R.~Azevedo and B.~Badelek and F.~Balestra and J.~Barth and R.~Beck and Y.~Bedfer and J.~Bernhard and K.~Bicker and E.~R.~Bielert and R.~Birsa and J.~Bisplinghoff and M.~Bodlak and M.~Boer and P.~Bordalo and F.~Bradamante and C.~Braun and A.~Bressan and M.~Buechele and L.~Capozza and W.-C.~Chang and C.~Chatterjee and M.~Chiosso and I.~Choi and S.-U.~Chung and A.~Cicuttin and M.L.~Crespo and Q.~Curiel and S.~Dalla Torre and S.S.~Dasgupta and S.~Dasgupta and O.Yu.~Denisov and L.~Dhara and S.V.~Donskov and N.~Doshita and V.~Duic and W.~Duennweber and M.~Dziewiecki and A.~Efremov and P.D.~Eversheim and W.~Eyrich and M.~Faessler and A.~Ferrero and M.~Finger and M.~Finger jr.~and H.~Fischer and C.~Franco and N.~du Fresne von Hohenesche and J.M.~Friedrich and V.~Frolov and E.~Fuchey and F.~Gautheron and O.P.~Gavrichtchouk and S.~Gerassimov and F.~Giordano and I.~Gnesi and M.~Gorzellik and S.~Grabmueller and A.~Grasso and M.~Grosse Perdekamp and B.~Grube and T.~Grussenmeyer and A.~Guskov and F.~Haas and D.~Hahne and D.~von Harrach and R.~Hashimoto and F.H.~Heinsius and R.~Heitz and F.~Herrmann and F.~Hinterberger and N.~Horikawa and N.~dHose and C.-Y.~Hsieh and S.~Huber and S.~Ishimoto and A.~Ivanov and Yu.~Ivanshin and T.~Iwata and R.~Jahn and V.~Jary and R.~Joosten and P.~Joerg and E.~Kabuss and B.~Ketzer and G.V.~Khaustov and Yu.A.~Khokhlov and Yu.~Kisselev and F.~Klein and K.~Klimaszewski and J.H.~Koivuniemi and V.N.~Kolosov and K.~Kondo and K.~Koenigsmann and I.~Konorov and V.F.~Konstantinov and A.M.~Kotzinian and O.M.~Kouznetsov and R.~Kuhn and M.~Kraemer and P.~Kremser and F.~Krinner and Z.V.~Kroumchtein and Y.~Kulinich and F.~Kunne and K.~Kurek and R.P.~Kurjata and A.A.~Lednev and A.~Lehmann and M.~Levillain and S.~Levorato and J.~Lichtenstadt and R.~Longo and A.~Maggiora and A.~Magnon and N.~Makins and N.~Makke and G.K.~Mallot and C.~Marchand and B.~Marianski and A.~Martin and J.~Marzec and J.~Matousek and H.~Matsuda and T.~Matsuda and G.V.~Meshcheryakov and W.~Meyer and T.~Michigami and Yu.V.~Mikhailov and M.~Mikhasenko and E.~Mitrofanov and N.~Mitrofanov and Y.~Miyachi and P.~Montuenga and A.~Nagaytsev and F.~Nerling and D.~Neyret and V.I.~Nikolaenko and J.~Novy and W.-D.~Nowak and G.~Nukazuka and A.S.~Nunes and A.G.~Olshevsky and I.~Orlov and M.~Ostrick and D.~Panzieri and B.~Parsamyan and S.~Paul and J.-C.~Peng and F.~Pereira and M.~Pesek and D.V.~Peshekhonov and S.~Platchkov and J.~Pochodzalla and V.A.~Polyakov and J.~Pretz and M.~Quaresma and C.~Quintans and S.~Ramos and C.~Regali and G.~Reicherz and C.~Riedl and M.~Roskot and D.I.~Ryabchikov and A.~Rybnikov and A.~Rychter and R.~Salac and V.D.~Samoylenko and A.~Sandacz and C.~Santos and S.~Sarkar and I.A.~Savin and T.~Sawada and G.~Sbrizzai and P.~Schiavon and K.~Schmidt and H.~Schmieden and K.~Schoenning and S.~Schopferer and E.~Seder and A.~Selyunin and O.Yu.~Shevchenko and D.~Steffen and L.~Silva and L.~Sinha and S.~Sirtl and M.~Slunecka and J.~Smolik and F.~Sozzi and A.~Srnka and M.~Stolarski and M.~Sulc and H.~Suzuki and A.~Szabelski and T.~Szameitat and P.~Sznajder and S.~Takekawa and M.~Tasevsky and S.~Tessaro and F.~Tessarotto and F.~Thibaud and F.~Tosello and V.~Tskhay and S.~Uhl and J.~Veloso and M.~Virius and J.~Vondra and T.~Weisrock and M.~Wilfert and R.~Windmolders and J.~ter Wolbeek and K.~Zaremba and P.~Zavada and M.~Zavertyaev and E.~Zemlyanichkina and M.~Ziembicki and A.~Zink}, title = {{M}ultiplicities of charged pions and unidentified charged hadrons from deep-inelastic scattering of muons off an isoscalar target}, year = {2016}, eprint = {1604.02695}, note = {arXiv:1604.02695v2} }
PDF
Multiplicities of charged pions and unidentified hadrons produced in deep-inelastic scattering were measured in bins of the Bjorken scaling variable $x$, the relative virtual-photon energy $y$ and the relative hadron energy $z$. Data were obtained by the COMPASS Collaboration using a 160 GeV muon beam and an isoscalar target ($^6$LiD). They cover the kinematic domain in the photon virtuality $Q^2$ > 1(GeV/c$)^2$, $0.004 < x < 0.4$, $0.2 < z < 0.85$ and $0.1 < y < 0.7$. In addition, a leading-order pQCD analysis was performed using the pion multiplicity results to extract quark fragmentation functions.
Leading-order determination of the gluon polarisation from semi-inclusive deep inelastic scattering data
C. Adolph, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badelek, F. Balestra, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E. R. Bielert, et al (201)
Dec 17 2015 hep-ex hep-ph arXiv:1512.05053v2

@misc{1512.05053, author = {C.~Adolph and M.~Aghasyan and R.~Akhunzyanov and M.G.~Alexeev and G.D.~Alexeev and A.~Amoroso and V.~Andrieux and N.V.~Anfimov and V.~Anosov and W.~Augustyniak and A.~Austregesilo and C.D.R.~Azevedo and B.~Badelek and F.~Balestra and J.~Barth and R.~Beck and Y.~Bedfer and J.~Bernhard and K.~Bicker and E.~R.~Bielert and R.~Birsa and J.~Bisplinghoff and M.~Bodlak and M.~Boer and P.~Bordalo and F.~Bradamante and C.~Braun and A.~Bressan and M.~Buechele and W.-C.~Chang and M.~Chiosso and I.~Choi and S.-U.~Chung and A.~Cicuttin and M.L.~Crespo and Q.~Curiel and S.~Dalla Torre and S.S.~Dasgupta and S.~Dasgupta and O.Yu.~Denisov and L.~Dhara and S.V.~Donskov and N.~Doshita and V.~Duic and W.~Duennweber and M.~Dziewiecki and A.~Efremov and P.D.~Eversheim and W.~Eyrich and M.~Faessler and A.~Ferrero and M.~Finger and M.~Finger jr.~and H.~Fischer and C.~Franco and N.~du Fresne von Hohenesche and J.M.~Friedrich and V.~Frolov and E.~Fuchey and F.~Gautheron and O.P.~Gavrichtchouk and S.~Gerassimov and F.~Giordano and I.~Gnesi and M.~Gorzellik and S.~Grabmueller and A.~Grasso and M.~Grosse Perdekamp and B.~Grube and T.~Grussenmeyer and A.~Guskov and F.~Haas and D.~Hahne and D.~von Harrach and R.~Hashimoto and F.H.~Heinsius and R.~Heitz and F.~Herrmann and F.~Hinterberger and N.~Horikawa and N.~d'Hose and C.-Y.~Hsieh and S.~Huber and S.~Ishimoto and A.~Ivanov and Yu.~Ivanshin and T.~Iwata and R.~Jahn and V.~Jary and R.~Joosten and P.~Joerg and E.~Kabuss and B.~Ketzer and G.V.~Khaustov and Yu.A.~Khokhlov and Yu.~Kisselev and F.~Klein and K.~Klimaszewski and J.H.~Koivuniemi and V.N.~Kolosov and K.~Kondo and K.~Koenigsmann and I.~Konorov and V.F.~Konstantinov and A.M.~Kotzinian and O.M.~Kouznetsov and M.~Kraemer and P.~Kremser and F.~Krinner and Z.V.~Kroumchtein and Y.~Kulinich and F.~Kunne and K.~Kurek and R.P.~Kurjata and A.A.~Lednev and A.~Lehmann and M.~Levillain and S.~Levorato and J.~Lichtenstadt and R.~Longo and A.~Maggiora and A.~Magnon and N.~Makins and N.~Makke and G.K.~Mallot and C.~Marchand and B.~Marianski and A.~Martin and J.~Marzec and J.~Matousek and H.~Matsuda and T.~Matsuda and G.V.~Meshcheryakov and W.~Meyer and T.~Michigami and Yu.V.~Mikhailov and M.~Mikhasenko and Y.~Miyachi and P.~Montuenga and A.~Nagaytsev and F.~Nerling and D.~Neyret and V.I.~Nikolaenko and J.~Novy and W.-D.~Nowak and G.~Nukazuka and A.S.~Nunes and A.G.~Olshevsky and I.~Orlov and M.~Ostrick and D.~Panzieri and B.~Parsamyan and S.~Paul and J.-C.~Peng and F.~Pereira and M.~Pesek and D.V.~Peshekhonov and S.~Platchkov and J.~Pochodzalla and V.A.~Polyakov and J.~Pretz and M.~Quaresma and C.~Quintans and S.~Ramos and C.~Regali and G.~Reicherz and C.~Riedl and M.~Roskot and N.S.~Rossiyskaya and D.I.~Ryabchikov and A.~Rybnikov and A.~Rychter and R.~Salac and V.D.~Samoylenko and A.~Sandacz and C.~Santos and S.~Sarkar and I.A.~Savin and T.~Sawada and G.~Sbrizzai and P.~Schiavon and K.~Schmidt and H.~Schmieden and K.~Schoenning and S.~Schopferer and E.~Seder and A.~Selyunin and O.Yu.~Shevchenko and L.~Silva and L.~Sinha and S.~Sirtl and M.~Slunecka and J.~Smolik and F.~Sozzi and A.~Srnka and M.~Stolarski and M.~Sulc and H.~Suzuki and A.~Szabelski and T.~Szameitat and P.~Sznajder and S.~Takekawa and M.~Tasevsky and S.~Tessaro and F.~Tessarotto and F.~Thibaud and F.~Tosello and V.~Tskhay and S.~Uhl and J.~Veloso and M.~Virius and J.~Vondra and T.~Weisrock and M.~Wilfert and J.~ter Wolbeek and K.~Zaremba and P.~Zavada and M.~Zavertyaev and E.~Zemlyanichkina and M.~Ziembicki and A.~Zink}, title = {{L}eading-order determination of the gluon polarisation from semi-inclusive deep inelastic scattering data}, year = {2015}, eprint = {1512.05053}, note = {arXiv:1512.05053v2} }
PDF
Using a novel analysis technique, the gluon polarisation in the nucleon is re-evaluated using the longitudinal double-spin asymmetry measured in the cross section of semi-inclusive single-hadron muoproduction with photon virtuality $Q^2>1~({\rm GeV}/c)^2$. The data were obtained by the COMPASS experiment at CERN using a 160 GeV/$c$ polarised muon beam impinging on a polarised $^6$LiD target. By analysing the full range in hadron transverse momentum $p_{\rm T}$, the different $p_{\rm T}$-dependences of the underlying processes are separated using a neural-network approach. In the absence of pQCD calculations at next-to-leading order in the selected kinematic domain, the gluon polarisation $\Delta g/g$ is evaluated at leading order in pQCD at a hard scale of $\mu^2= \langle Q^2 \rangle = 3 ({\rm GeV}/c)^2$. It is determined in three intervals of the nucleon momentum fraction carried by gluons, $x_{\rm g}$, covering the range $0.04 \!<\! x_{ \rm g}\! <\! 0.28$~ and does not exhibit a significant dependence on $x_{\rm g}$. The average over the three intervals, $\langle \Delta g/g \rangle = 0.113 \pm 0.038_{\rm (stat.)}\pm 0.036_{\rm (syst.)}$ at $\langle x_{\rm g} \rangle \approx 0.10$, suggests that the gluon polarisation is positive in the measured $x_{\rm g}$ range.
Studies of Transverse Momentum Dependent Parton Distributions and Bessel Weighting
M. Aghasyan, H. Avakian, E. De Sanctis, L. Gamberg, M. Mirazita, B. Musch, A. Prokudin, P. Rossi
Sep 02 2014 hep-ph hep-ex arXiv:1409.0487v2

@misc{1409.0487, author = {M.~Aghasyan and H.~Avakian and E.~De Sanctis and L.~Gamberg and M.~Mirazita and B.~Musch and A.~Prokudin and P.~Rossi}, title = {{S}tudies of {T}ransverse {M}omentum {D}ependent {P}arton {D}istributions and {B}essel {W}eighting}, year = {2014}, eprint = {1409.0487}, note = {arXiv:1409.0487v2} }
PDF
In this paper we present a new technique for analysis of transverse momentum dependent parton distribution functions, based on the Bessel weighting formalism. The procedure is applied to studies of the double longitudinal spin asymmetry in semi-inclusive deep inelastic scattering using a new dedicated Monte Carlo generator which includes quark intrinsic transverse momentum within the generalized parton model. Using a fully differential cross section for the process, the effect of four momentum conservation is analyzed using various input models for transverse momentum distributions and fragmentation functions. We observe a few percent systematic offset of the Bessel-weighted asymmetry obtained from Monte Carlo extraction compared to input model calculations, which is due to the limitations imposed by the energy and momentum conservation at the given energy/Q2. We find that the Bessel weighting technique provides a powerful and reliable tool to study the Fourier transform of TMDs with controlled systematics due to experimental acceptances and resolutions with different TMD model inputs.
Studies of TMDs with CLAS
M. Aghasyan, H. Avakian
Jul 15 2013 hep-ex arXiv:1307.3500v1

@misc{1307.3500, author = {M.~Aghasyan and H.~Avakian}, title = {{S}tudies of {TMD}s with {CLAS}}, year = {2013}, eprint = {1307.3500}, note = {arXiv:1307.3500v1} }
PDF
Studies of single and double-spin asymmetries in pion electro-production in semi-inclusive deep-inelastic scattering of 5.8 GeV polarized electrons from unpolarized and longitudinally polarized targets at the Thomas Jefferson National Accelerator Facility using CLAS discussed. We present a Bessel-weighting strategy to extract transverse-momentum-dependent parton distribution functions.
Fully Differential Monte-Carlo Generator Dedicated to TMDs and Bessel-Weighted Asymmetries
M. Aghasyan, H.Avakian
Mar 18 2013 hep-ph hep-ex arXiv:1303.3722v2

@misc{1303.3722, author = {M.~Aghasyan and H.Avakian}, title = {{F}ully {D}ifferential {M}onte-{C}arlo {G}enerator {D}edicated to {TMD}s and {B}essel-{W}eighted {A}symmetries}, year = {2013}, eprint = {1303.3722}, note = {arXiv:1303.3722v2} }
PDF
We present studies of double longitudinal spin asymmetries in semi-inclusive deep inelastic scattering using a new dedicated Monte Carlo generator, which includes quark intrinsic transverse momentum within the generalized parton model based on the fully differential cross section for the process. Additionally, we apply Bessel-weighting to the simulated events to extract transverse momentum dependent parton distribution functions and also discuss possible uncertainties due to kinematic correlation effects.
Extracting TMDs from CLAS12 data
M. Aghasyan, H. Avakian
Feb 06 2013 hep-ex hep-ph arXiv:1302.1080v3

@misc{1302.1080, author = {M.~Aghasyan and H.~Avakian}, title = {{E}xtracting {TMD}s from {CLAS}12 data}, year = {2013}, eprint = {1302.1080}, note = {arXiv:1302.1080v3} }
PDF
We present studies of double longitudinal spin asymmetries in semi-inclusive deep inelastic scattering using a new dedicated Monte Carlo generator, which includes quark intrinsic transverse momentum within the generalized parton model based on the fully differential cross section for the process. Additionally we employ Bessel-weighting to the MC events to extract transverse momentum dependent parton distribution functions and also discuss possible uncertainties due to kinematic correlation effects.
Measurement of Exclusive $\pi^0$ Electroproduction Structure Functions and their Relationship to Transversity GPDs
CLAS Collaboration, I. Bedlinskiy, V. Kubarovsky, S. Niccolai, P. Stoler, K. P. Adhikari, M. Aghasyan, M. J. Amaryan, M. Anghinolfi, H. Avakian, H. Baghdasaryan, J. Ball, N.A. Baltzell, M. Battaglieri, R. P. Bennett, A. S. Biselli, C. Bookwalter, S. Boiarinov, W. J. Briscoe, W. K. Brooks, et al (134)
Jun 28 2012 hep-ex hep-ph nucl-ex arXiv:1206.6355v2

@misc{1206.6355, author = {CLAS Collaboration and I.~Bedlinskiy and V.~Kubarovsky and S.~Niccolai and P.~Stoler and K.~P.~Adhikari and M.~Aghasyan and M.~J.~Amaryan and M.~Anghinolfi and H.~Avakian and H.~Baghdasaryan and J.~Ball and N.A.~Baltzell and M.~Battaglieri and R.~P.~Bennett and A.~S.~Biselli and C.~Bookwalter and S.~Boiarinov and W.~J.~Briscoe and W.~K.~Brooks and V.~D.~Burkert and D.~S.~Carman and A.~Celentano and S.~Chandavar and G.~Charles and M.~Contalbrigo and V.~Crede and A.~D'Angelo and A.~Daniel and N.~Dashyan and R.~De Vita and E.~De Sanctis and A.~Deur and C.~Djalali and D.~Doughty and R.~Dupre and H.~Egiyan and A.~El Alaoui and L.~El Fassi and L.~Elouadrhiri and P.~Eugenio and G.~Fedotov and S.~Fegan and J.~A.~Fleming and T.~A.~Forest and M.~Garçon and N.~Gevorgyan and K.~L.~Giovanetti and F.~X.~Girod and W.~Gohn and R.~W.~Gothe and L.~Graham and K.~A.~Griffioen and B.~Guegan and M.~Guidal and L.~Guo and K.~Hafidi and H.~Hakobyan and C.~Hanretty and D.~Heddle and K.~Hicks and M.~Holtrop and Y.~Ilieva and D.~G.~Ireland and B.~S.~Ishkhanov and E.~L.~Isupov and H.~S.~Jo and K.~Joo and D.~Keller and M.~Khandaker and P.~Khetarpal and A.~Kim and W.~Kim and F.~J.~Klein and S.~Koirala and A.~Kubarovsky and S.~E.~Kuhn and S.~V.~Kuleshov and N.~D.~Kvaltine and K.~Livingston and H.~Y.~Lu and I.~J.~D.~MacGregor and Y.~Mao and N.~Markov and D.~Martinez and M.~Mayer and B.~McKinnon and C.~A.~Meyer and T.~Mineeva and M.~Mirazita and V.~Mokeev and H.~Moutarde and E.~Munevar and C.~Munoz Camacho and P.~Nadel-Turonski and G.~Niculescu and I.~Niculescu and M.~Osipenko and A.~I.~Ostrovidov and L.~L.~Pappalardo and R.~Paremuzyan and K.~Park and S.~Park and E.~Pasyuk and S.~Anefalos Pereira and E.~Phelps and S.~Pisano and O.~Pogorelko and S.~Pozdniakov and J.~W.~Price and S.~Procureur and Y.~Prok and D.~Protopopescu and A.~J.~R.~Puckett and B.~A.~Raue and G.~Ricco and D.~Rimal and M.~Ripani and G.~Rosner and P.~Rossi and F.~Sabatié and M.~S.~Saini and C.~Salgado and N.~Saylor and D.~Schott and R.~A.~Schumacher and E.~Seder and H.~Seraydaryan and Y.~G.~Sharabian and G.~D.~Smith and D.~I.~Sober and D.~Sokhan and S.~S.~Stepanyan and S.~Stepanyan and S.~Strauch and M.~Taiuti and W.~Tang and C.~E.~Taylor and Ye Tian and S.~Tkachenko and M.~Ungaro and M.~F.~Vineyard and A.~Vlassov and H.~Voskanyan and E.~Voutier and N.~K.~Walford and D.~P.~Watts and L.~B.~Weinstein and D.~P.~Weygand and M.~H.~Wood and N.~Zachariou and J.~Zhang and Z.~W.~Zhao and I.~Zonta}, title = {{M}easurement of {E}xclusive $\pi^0$ {E}lectroproduction {S}tructure {F}unctions and their {R}elationship to {T}ransversity {GPD}s}, year = {2012}, eprint = {1206.6355}, howpublished = {PRL 109, 112001 (2012)}, doi = {10.1103/PhysRevLett.109.112001}, note = {arXiv:1206.6355v2} }
PDF
Exclusive $\pi^0$ electroproduction at a beam energy of 5.75 GeV has been measured with the Jefferson Lab CLAS spectrometer. Differential cross sections were measured at more than 1800 kinematic values in $Q^2$, $x_B$, $t$, and $\phi_\pi$, in the $Q^2$ range from 1.0 to 4.6 GeV$^2$,\ $-t$ up to 2 GeV$^2$, and $x_B$ from 0.1 to 0.58. Structure functions $\sigma_T +\epsilon \sigma_L, \sigma_{TT}$ and $\sigma_{LT}$ were extracted as functions of $t$ for each of 17 combinations of $Q^2$ and $x_B$. The data were compared directly with two handbag-based calculations including both longitudinal and transversity GPDs. Inclusion of only longitudinal GPDs very strongly underestimates $\sigma_T +\epsilon \sigma_L$ and fails to account for $\sigma_{TT}$ and $\sigma_{LT}$, while inclusion of transversity GPDs brings the calculations into substantially better agreement with the data. There is very strong sensitivity to the relative contributions of nucleon helicity flip and helicity non-flip processes. The results confirm that exclusive $\pi^0$ electroproduction offers direct experimental access to the transversity GPDs.
Measurement of the neutron F2 structure function via spectator tagging with CLAS
N. Baillie, S. Tkachenko, J. Zhang, P. Bosted, S. Bultmann, M. E. Christy, H. Fenker, K. A. Griffioen, C. E. Keppel, S. E. Kuhn, W. Melnitchouk, V. Tvaskis, K. P. Adhikari, D. Adikaram, M. Aghasyan, M. J. Amaryan, M. Anghinolfini, J. Arrington, H. Avakian, H. Baghdasaryan, et al (130)
Oct 13 2011 nucl-ex hep-ex arXiv:1110.2770v3

@misc{1110.2770, author = {N.~Baillie and S.~Tkachenko and J.~Zhang and P.~Bosted and S.~Bultmann and M.~E.~Christy and H.~Fenker and K.~A.~Griffioen and C.~E.~Keppel and S.~E.~Kuhn and W.~Melnitchouk and V.~Tvaskis and K.~P.~Adhikari and D.~Adikaram and M.~Aghasyan and M.~J.~Amaryan and M.~Anghinolfini and J.~Arrington and H.~Avakian and H.~Baghdasaryan and M.~Battaglieri and A.~S.~Biselli and 5 D.~Branford and W.~J.~Briscoe and W.~K.~Brooks and V.~D.~Burkert and D.~S.~Carman and A.~Celentano and S.~Chandavar and G.~Charles and P.~L.~Cole and M.~Contalbrigo and V.~Crede and A.~D'Angelo and A.~Daniel and N.~Dashyan and R.~De Vita and E.~De Sanctis and A.~Deur and B.~Dey and C.~Djalali and G.~Dodge and J.~Domingo and D.~Doughty and R.~Dupre and D.~Dutta and R.~Ent and H.~Egiyan and A.~El Alaoui and L.~El Fassi and L.~Elouadrhiri and P.~Eugenio and G.~Fedotov and S.~Fegan and A.~Fradi and M.~Y.~Gabrielyan and N.~Gevorgyan and G.~P.~Gilfoyle and K.~L.~Giovanetti and F.~X.~Girod and W.~Gohn and E.~Golovatch and R.~W.~Gothe and L.~Graham and B.~Guegan and M.~Guidal and N.~Guler and L.~Guo and K.~Hafidi and D.~Heddle and K.~Hicks and M.~Holtrop and E.~Hungerford and C.~E.~Hyde and Y.~Ilieva and D.~G.~Ireland and M.~Ispiryan and E.~L.~Isupov and S.~S.~Jawalkar and H.~S.~Jo and N.~Kalantarians and M.~Khandaker and P.~Khetarpal and A.~Kim and W.~Kim and P.~M.~King and A.~Klein and F.~J.~Klein and A.~Klimenko and V.~Kubarovsky and S.~V.~Kuleshov and N.~D.~Kvaltine and K.~Livingston and H.~Y.~Lu and I .~J .~D.~MacGregor and Y.~Mao and N.~Markov and B.~McKinnon and T.~Mineeva and B.~Morrison and H.~Moutarde and E.~Munevar and P.~Nadel-Turonski and A.~Ni and S.~Niccolai and I.~Niculescu and G.~Niculescu and M.~Osipenko and A.~I.~Ostrovidov and L.~Pappalardo and K.~Park and S.~Park and E.~Pasyuk and S.~Anefalos Pereira and S.~Pisano and S.~Pozdniakov and J.~W.~Price and S.~Procureur and Y.~Prok and D.~Protopopescu and B.~A.~Raue and G.~Ricco and D.~Rimal and M.~Ripani and G.~Rosner and P.~Rossi and F.~Sabatie and M.~S.~Saini and C.~Salgado and D.~Schott and R.~A.~Schumacher and E.~Seder and Y.~G.~Sharabian and D.~I.~Sober and D.~Sokhan and S.~Stepanyan and S.~S.~Stepanyan and P.~Stoler and S.~Strauch and M.~Taiuti and W.~Tang and M.~Ungaro and M.~F.~Vineyard and E.~Voutier and D.~P.~Watts and L.~B.~Weinstein and D.~P.~Weygand and M.~H.~Wood and L.~Zana and B.~Zhao}, title = {{M}easurement of the neutron {F}2 structure function via spectator tagging with {CLAS}}, year = {2011}, eprint = {1110.2770}, howpublished = {Phys. Rev. Lett. 108, 199902 (2012)}, doi = {10.1103/PhysRevLett.108.142001}, note = {arXiv:1110.2770v3} }
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We report on the first measurement of the F2 structure function of the neutron from semi-inclusive scattering of electrons from deuterium, with low-momentum protons detected in the backward hemisphere. Restricting the momentum of the spectator protons to < 100 MeV and their angles to < 100 degrees relative to the momentum transfer allows an interpretation of the process in terms of scattering from nearly on-shell neutrons. The F2n data collected cover the nucleon resonance and deep-inelastic regions over a wide range of Bjorken x for 0.65 < Q2 < 4.52 GeV2, with uncertainties from nuclear corrections estimated to be less than a few percent. These measurements provide the first determination of the neutron to proton structure function ratio F2n/F2p at 0.2 < x < 0.8 with little uncertainty due to nuclear effects.
Precise Measurements of Beam Spin Asymmetries in Semi-Inclusive $\pi^0$ production
M. Aghasyan, H. Avakian, P. Rossi, E. De Sanctis, D. Hasch, M. Mirazita, D. Adikaram, M.J. Amaryan, M. Anghinolfi, H. Baghdasaryan, J. Ball, M. Battaglieri, V. Batourine, I. Bedlinskiy, R. P. Bennett, A.S. Biselli, D. Branford, W.J. Briscoe, S. Bültmann, V.D. Burkert, et al (134)
Jun 14 2011 hep-ex arXiv:1106.2293v2

@misc{1106.2293, author = {M.~Aghasyan and H.~Avakian and P.~Rossi and E.~De Sanctis and D.~Hasch and M.~Mirazita and D.~Adikaram and M.J.~Amaryan and M.~Anghinolfi and H.~Baghdasaryan and J.~Ball and M.~Battaglieri and V.~Batourine and I.~Bedlinskiy and R.~P.~Bennett and A.S.~Biselli and D.~Branford and W.J.~Briscoe and S.~Bültmann and V.D.~Burkert and D.S.~Carman and S.~Chandavar and P.L.~Cole and P.~Collins and M.~Contalbrigo and V.~Crede and A.~D'Angelo and A.~Daniel and N.~Dashyan and R.~De Vita and A.~Deur and B.~Dey and R.~Dickson and C.~Djalali and G.E.~Dodge and D.~Doughty and R.~Dupre and H.~Egiyan and A.~El Alaoui and L.~Elouadrhiri and P.~Eugenio and G.~Fedotov and S.~Fegan and A.~Fradi and M.Y.~Gabrielyan and M.~Garçon and N.~Gevorgyan and G.P.~Gilfoyle and K.L.~Giovanetti and F.X.~Girod and J.T.~Goetz and W.~Gohn and E.~Golovatch and R.W.~Gothe and L.~Graham and K.A.~Griffioen and B.~Guegan and M.~Guidal and N.~Guler and L.~Guo and K.~Hafidi and C.~Hanretty and K.~Hicks and M.~Holtrop and C.E.~Hyde and Y.~Ilieva and D.G.~Ireland and E.L.~Isupov and S.S.~Jawalkar and D.~Jenkins and H.S.~Jo and K.~Joo and D.~Keller and M.~Khandaker and P.~Khetarpal and A.~Kim and W.~Kimy and A.~Klein and F.J.~Klein and V.~Kubarovsky and S.E.~Kuhn and S.V.~Kuleshov and V.~Kuznetsov and N.D.~Kvaltine and K.~Livingston and H.Y.~Lu and I .J .D.~MacGregor and N.~Markov and M.~Mayer and J.~McAndrew and B.~McKinnon and C.A.~Meyer and A.M.~Micherdzinska and V.~Mokeev and B.~Moreno and H.~Moutarde and E.~Munevar and P.~Nadel-Turonski and A.~Ni and S.~Niccolai and G.~Niculescu and I.~Niculescu and M.~Osipenko and A.I.~Ostrovidov and M.~Paolone and L.~Pappalardo and R.~Paremuzyan and K.~Park and S.~Park and E.~Pasyuk and S.~Anefalos Pereira and E.~Phelps and S.~Pisano and O.~Pogorelko and S.~Pozdniakov and J.W.~Price and S.~Procureur and Y.~Prok and D.~Protopopescu and B.A.~Raue and G.~Ricco and D.~Rimal and M.~Ripani and G.~Rosner and F.~Sabatié and M.S.~Saini and C.~Salgado and D.~Schott and R.A.~Schumacher and E.~Seder and H.~Seraydaryan and Y.G.~Sharabian and G.D.~Smith and D.I.~Sober and S.S.~Stepanyan and S.~Stepanyan and P.~Stoler and I.~Strakovsky and S.~Strauch and M.~Taiuti and W.~Tang and C.E.~Taylor and S.~Tkachenko and M.~Ungaro and H.~Voskanyan and E.~Voutier and D.~Watts and L.B.~Weinstein and D.P.~Weygand and M.H.~Wood and L.~Zana and J.~Zhang and B.~Zhao and Z.W.~Zhao}, title = {{P}recise {M}easurements of {B}eam {S}pin {A}symmetries in {S}emi-{I}nclusive $\pi^0$ production}, year = {2011}, eprint = {1106.2293}, howpublished = {Phys.Lett.B704:397-402,2011}, doi = {10.1016/j.physletb.2011.09.044}, note = {arXiv:1106.2293v2} }
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We present studies of single-spin asymmetries for neutral pion electroproduction in semi-inclusive deep-inelastic scattering of 5.776 GeV polarized electrons from an unpolarized hydrogen target, using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. A substantial $\sin \phi_h$ amplitude has been measured in the distribution of the cross section asymmetry as a function of the azimuthal angle $\phi_h$ of the produced neutral pion. The dependence of this amplitude on Bjorken $x$ and on the pion transverse momentum is extracted with significantly higher precision than previous data and is compared to model calculations.
Studies of spin-orbit correlations at JLAB
Mher Aghasyan, Harut Avakian
Mar 17 2011 hep-ex arXiv:1103.3194v1

@misc{1103.3194, author = {Mher Aghasyan and Harut Avakian}, title = {{S}tudies of spin-orbit correlations at {JLAB}}, year = {2011}, eprint = {1103.3194}, howpublished = {J.Phys.Conf.Ser.295:012063,2011}, doi = {10.1088/1742-6596/295/1/012063}, note = {arXiv:1103.3194v1} }
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Studies of single spin asymmetries for pion electroproduction in semi-inclusive deep-inelastic scattering are presented using the polarized \sim6 GeV electrons from at the Thomas Jefferson National Accelerator Facility (JLab) and the Continuous Electron Beam Accelerator Facility (CEBAF) Large Acceptance Spectrometer (CLAS) with the Inner Calorimeter. The cross section versus the azimuthal angle \phi_h of the produced neutral pion has a substantial sin \phi_h amplitude. The dependence of this amplitude on Bjorken x_B and on the pion transverse momentum is extracted and compared with published data.