R. Astalos, S. Baranov, P. Bartalini, I. Belyaev, Ch. Bierlich, B. Blok, A. Buckley, F. A. Ceccopieri, I. Cherednikov, J. R. Christiansen, D. Ciangottini, M. Deak, B. Ducloue, R. Field, J. R. Gaunt, K. Golec-Biernat, L. Goerlich, A. Grebenyuk, O. Gueta, P. Gunnellini, et al (37) Multiple Partonic Interactions are often crucial for interpreting results obtained at the Large Hadron Collider (LHC). The quest for a sound understanding of the dynamics behind MPI - particularly at this time when the LHC is due to start its "Run II" operations - has focused the aim of this workshop. MPI@LHC2014 concentrated mainly on the phenomenology of LHC measurements whilst keeping in perspective those results obtained at previous hadron colliders. The workshop has also debated some of the state-of-the-art theoretical considerations and the modeling of MPI in Monte Carlo event generators. The topics debated in the workshop included: Phenomenology of MPI processes and multiparton distributions; Considerations for the description of MPI in Quantum Chromodynamics (QCD); Measuring multiple partonic interactions; Experimental results on inelastic hadronic collisions: underlying event, minimum bias, forward energy flow; Monte Carlo generator development and tuning; Connections with low-x phenomena, diffraction, heavy-ion physics and cosmic rays. In a total of 57 plenary talks the workshop covered a wide range of experimental results, Monte Carlo development and tuning, phenomenology and dedicated measurements of MPI which were produced with data from the LHC's Run I. Recent progress of theoretical understanding of MPI in pp, pA and AA collisions as well as the role of MPI in diffraction and small-x physics were also covered. The workshop forstered close contact between the experimental and theoretical communities. It provided a setting to discuss many of the different aspects of MPI, eventually identifying them as a unifying concept between apparently different lines of research and evaluating their impact on the LHC physics programme.
H. Abramowicz, P. Bartalini, M. Baehr, N. Cartiglia, R. Ciesielski, E. Dobson, F. Ferro, K. Goulianos, B. Guiot, X. Janssen, H. Jung, Iu. Karpenko, J. Kaspar, J. Katzy, F. Krauss, P. Laycock, E. Levin, M. Mangano, Ch. Mesropian, A. Moraes, et al (17) Jun 25 2013
hep-ph arXiv:1306.5413v2
With short resumes and highlights the discussions in the different working groups of the workshop MPI@LHC 2012 is documented.
TeV4LHC QCD Working Group, M. Albrow, M. Begel, D. Bourilkov, M. Campanelli, F. Chlebana, A. De Roeck, J.R. Dittmann, S.D. Ellis, B. Field, R. Field, M. Gallinaro, W. Giele, K. Goulianos, R.C. Group, K. Hatakeyama, Z. Hubacek, J. Huston, W. Kilgore, T. Kluge, et al (14) Oct 03 2006
hep-ph arXiv:hep-ph/0610012v1
The experiments at Run 2 of the Tevatron have each accumulated over 1 inverse femtobarn of high-transverse momentum data. Such a dataset allows for the first precision (i.e. comparisons between theory and experiment at the few percent level) tests of QCD at a hadron collider. While the Large Hadron Collider has been designed as a discovery machine, basic QCD analyses will still need to be performed to understand the working environment. The Tevatron-for-LHC workshop was conceived as a communication link to pass on the expertise of the Tevatron and to test new analysis ideas coming from the LHC community. The TeV4LHC QCD Working Group focussed on important aspects of QCD at hadron colliders: jet definitions, extraction and use of Parton Distribution Functions, the underlying event, Monte Carlo tunes, and diffractive physics. This report summarizes some of the results achieved during this workshop.
C.Buttar, S.Dittmaier, V.Drollinger, S.Frixione, A.Nikitenko, S.Willenbrock S.Abdullin, E.Accomando, D.Acosta, A.Arbuzov, R.D.Ball, A.Ballestrero, P.Bartalini, U.Baur, A.Belhouari, S.Belov, A.Belyaev, D.Benedetti, T.Binoth, S.Bolognesi, S.Bondarenko, et al (106) Apr 14 2006
hep-ph arXiv:hep-ph/0604120v1
This Report summarises the activities of the "SM and Higgs" working group for the Workshop "Physics at TeV Colliders", Les Houches, France, 2-20 May, 2005. On the one hand, we performed a variety of experimental and theoretical studies on standard candles (such as W, Z, and ttbar production), treating them either as proper signals of known physics, or as backgrounds to unknown physics; we also addressed issues relevant to those non-perturbative or semi-perturbative ingredients, such as Parton Density Functions and Underlying Events, whose understanding will be crucial for a proper simulation of the actual events taking place in the detectors. On the other hand, several channels for the production of the Higgs, or involving the Higgs, have been considered in some detail. The report is structured into four main parts. The first one deals with Standard Model physics, except the Higgs. A variety of arguments are treated here, from full simulation of processes constituting a background to Higgs production, to studies of uncertainties due to PDFs and to extrapolations of models for underlying events, from small-$x$ issues to electroweak corrections which may play a role in vector boson physics. The second part of the report treats Higgs physics from the point of view of the signal. In the third part, reviews are presented on the current status of multi-leg, next-to-leading order and of next-to-next-to-leading order QCD computations. Finally, the fourth part deals with the use of Monte Carlos for simulation of LHC physics.
S. Alekhin, G. Altarelli, N. Amapane, J. Andersen, V. Andreev, M. Arneodo, V. Avati, J. Baines, R.D. Ball, A. Banfi, S.P. Baranov, J. Bartels, O. Behnke, R. Bellan, J. Blumlein, H. Bottcher, S. Bolognesi, M. Boonekamp, D. Bourilkov, J. Bracinik, et al (174) Jan 03 2006
hep-ph arXiv:hep-ph/0601012v3
The HERA electron--proton collider has collected 100 pb$^{-1}$ of data since its start-up in 1992, and recently moved into a high-luminosity operation mode, with upgraded detectors, aiming to increase the total integrated luminosity per experiment to more than 500 pb$^{-1}$. HERA has been a machine of excellence for the study of QCD and the structure of the proton. The Large Hadron Collider (LHC), which will collide protons with a centre-of-mass energy of 14 TeV, will be completed at CERN in 2007. The main mission of the LHC is to discover and study the mechanisms of electroweak symmetry breaking, possibly via the discovery of the Higgs particle, and search for new physics in the TeV energy scale, such as supersymmetry or extra dimensions. Besides these goals, the LHC will also make a substantial number of precision measurements and will offer a new regime to study the strong force via perturbative QCD processes and diffraction. For the full LHC physics programme a good understanding of QCD phenomena and the structure function of the proton is essential. Therefore, in March 2004, a one-year-long workshop started to study the implications of HERA on LHC physics. This included proposing new measurements to be made at HERA, extracting the maximum information from the available data, and developing/improving the theoretical and experimental tools. This report summarizes the results achieved during this workshop.
S. Alekhin, G. Altarelli, N. Amapane, J. Andersen, V. Andreev, M. Arneodo, V. Avati, J. Baines, R.D. Ball, A. Banfi, S.P. Baranov, J. Bartels, O. Behnke, R. Bellan, J. Blumlein, H. Bottcher, S. Bolognesi, M. Boonekamp, D. Bourilkov, J. Bracinik, et al (174) Jan 03 2006
hep-ph arXiv:hep-ph/0601013v3
The HERA electron--proton collider has collected 100 pb$^{-1}$ of data since its start-up in 1992, and recently moved into a high-luminosity operation mode, with upgraded detectors, aiming to increase the total integrated luminosity per experiment to more than 500 pb$^{-1}$. HERA has been a machine of excellence for the study of QCD and the structure of the proton. The Large Hadron Collider (LHC), which will collide protons with a centre-of-mass energy of 14 TeV, will be completed at CERN in 2007. The main mission of the LHC is to discover and study the mechanisms of electroweak symmetry breaking, possibly via the discovery of the Higgs particle, and search for new physics in the TeV energy scale, such as supersymmetry or extra dimensions. Besides these goals, the LHC will also make a substantial number of precision measurements and will offer a new regime to study the strong force via perturbative QCD processes and diffraction. For the full LHC physics programme a good understanding of QCD phenomena and the structure function of the proton is essential. Therefore, in March 2004, a one-year-long workshop started to study the implications of HERA on LHC physics. This included proposing new measurements to be made at HERA, extracting the maximum information from the available data, and developing/improving the theoretical and experimental tools. This report summarizes the results achieved during this workshop.
M. Dobbs, S. Frixione, E. Laenen, A. De Roeck, K. Tollefson, J. Andersen, C. Balazs, A. Banfi, S. Berge, W. Bernreuther, T. Binoth, A. Brandenburg, C. Buttar, Q-H. Cao, G. Corcella, A. Cruz, I. Dawson, V. Del Duca, V. Drollinger, L. Dudko, et al (35) Mar 10 2004
hep-ph arXiv:hep-ph/0403100v1
This report documents the results obtained by the Working Group on Quantum Chromodynamics and the Standard Model for the Workshop `Physics at TeV Colliders'', Les Houches, France, 26 May - 6 June 2003. After a Monte Guide description, the first contributions report on progress in describing multiple interactions, important for the LHC, and underlying events. An announcement of a Monte Carlo database, under construction, is then followed by a number of contributions improving parton shower descriptions. Subsequently, a large number of contributions address resummations in various forms, after which follow studies of QCD effects in pion pair, top quark pair and photon pair plus jet production. After a study of electroweak corrections to hadronic precision observables, the report ends by presenting recent progress in methods to compute finite order corrections at one-loop with many legs, and at two-loop.