Conveners
03 - Perturbative QCD, Jets and Diffractive Physics
- Gudrun Heinrich (University of Durham)
03 - Perturbative QCD, Jets and Diffractive Physics
- Leszek Motyka (Hamburg University)
03 - Perturbative QCD, Jets and Diffractive Physics
- Leszek Motyka (Hamburg University)
03 - Perturbative QCD, Jets and Diffractive Physics
- Gudrun Heinrich (University of Durham)
03 - Perturbative QCD, Jets and Diffractive Physics
- Laurent SCHOEFFEL (CEA Saclay)
03 - Perturbative QCD, Jets and Diffractive Physics
- Laurent SCHOEFFEL (CEA Saclay)
03 - Perturbative QCD, Jets and Diffractive Physics
- Nikos Varelas (Physics Department - University of Illinois at Chicago)
03 - Perturbative QCD, Jets and Diffractive Physics
- Nikos Varelas (Physics Department - University of Illinois at Chicago)
Frank Krauss
(University of Durham)
23/07/2010, 09:00
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
The status of the standard multi-purpose Monte Carlo tools for LHC physics is reviewed, with a special emphasis on recent developments. These include the systematic inclusion of higher-order corrections and the modelling of soft QCD.
Frank Siegert
(IPPP Durham and UC London)
23/07/2010, 09:30
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
Multi-jet merging of matrix elements and parton showers in Monte-Carlo event generators has become a crucial tool for LHC predictions. An existing algorithm for tree-level matrix elements is extended to full NLO accuracy.
Aleksander Kusina
(Institute of Nuclear Physics PAN)
23/07/2010, 09:50
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
We would like to present recent work, which is going to change three-decades old paradigm of perturbative QCD calculations, in which hard process matrix element calculated to LO+NLO(+NNLO) level is combined with: either the collinear PDF at LO+NLO(+NNLO) or with the Monte Carlo parton shower, but the MC PS restricted to LO only! For many years upgrading Monte Carlo parton shower to NLO level...
Prof.
Bennie Ward
(Baylor University)
23/07/2010, 10:10
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
By implementing the new IR-improved Dokshitzer-Gribov-Lipatov-Altarelli-Parisi-Callan-Symanzik (DGLAP-CS) kernels recently developed by one of us in the HERWIG6.5 environment we generate a new MC, HERWIRI1.0(31), for hadron-hadron scattering at high energies. We use MC data to illustrate the comparison between the parton shower generated by the standard DGLAP-CS kernels and that generated by...
Dr
tim coughlin
(university college london)
23/07/2010, 11:00
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
We investigate the theoretical description of the central exclusive production process. Taking Higgs production as an example, we sum logarithmically enhanced corrections appearing in the perturbation series to all orders in the strong coupling. In addition, we perform a fixed order calculation of the corrections relevant for the Sudakov factor appearing in the process. Both approaches agree...
Armen Bunyatyan
(DESY)
23/07/2010, 11:20
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
Diffractive cross sections of electroproduction of rho and phi mesons is measured at HERA with the H1 detector in the elastic and proton dissociative channels. The data correspond to an integrated luminosity of 51 pb^-1. Based on data collected with the H1 detector at HERA in 2005, cross sections or elastic rho photoproduction have been measured at momentum transfer |t| < 0.58 GeV^2 and...
Lech Szymanowski
(Soltan INS, Warsaw)
23/07/2010, 11:50
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
We describe a consistent approach to factorization of scattering amplitudes for exclusive processes beyond the leading twist approximation. The method is based on the Taylor expansion of the scattering amplitude in the momentum space around the dominant light-cone direction and thus naturally introduces an appropriate set of non-perturbative correlators which encode effects not only of the...
Royon Christophe
(DAPNIA)
23/07/2010, 12:10
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
After a brief description of the models of exclusive diffractive Higgs prodution, we first evaluate the theoretical uncertainties that affect the calculation of exclusive cross section (jets, Higgs...). In addition, in view of the recent measurement of exclusive dijet at CDF and the new implementation of the corresponding cross section in FPMC (Forward Physics Monte-Carlo), we developed an...
Prof.
Ian Balitsky
(JLab/ODU)
23/07/2010, 14:00
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
I review the calculation of the next-to-leading order behavior of high-energy amplitudes in N=4 SYM and QCD using the operator expansion in Wilson lines.
Paul Richard Newman
(School of Physics and Astronomy-University of Birmingham)
23/07/2010, 14:17
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
The production of highly energetic forward neutrons has been studied in deep-inelastic positron-proton scattering. The data were taken with the H1 detector at HERA in the years 2006-2007 and correspond to an integrated luminosity of 122 pb^-1. Semi-inclusive cross sections have been measured in the range of four momentum transfer squared 6 < Q^2 < 100 GeV^2, Bjorken scaling variable 1.5 *...
Samuel Wallon
(LPT, Université Paris-Sud, CNRS, Orsay and UPMC Univ. Paris 06)
23/07/2010, 14:37
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
We calculate cross section and azimuthal decorrellation of Mueller Navelet jets at the LHC in the complete next-lo-leading order BFKL framework, i.e. including next-to-leading corrections to the Green's function as well as next-to-leading corrections to the Mueller Navelet vertices.
The obtained results for standard observables proposed for studies of Mueller Navelet jets show that both...
Francesco Hautmann
(University of Oxford)
23/07/2010, 14:54
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
At the Large Hadron Collider (LHC) it will become possible for the first time to investigate experimentally the forward region in hadron-hadron collisions via high-p_T processes. In the LHC forward kinematics QCD logarithmic corrections in the hard transverse momentum and in the large rapidity interval may both be quantitatively significant. The theoretical framework to resum consistently...
Dr
Edmond Berger
(ANL)
23/07/2010, 15:11
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
We evaluate the kinematic distributions in phase space of 4-parton final-state subprocesses produced by double parton scattering, and we contrast these with the final-state distributions that originate from conventional single parton scattering. Our goal is to establish the distinct topologies of events that arise from these two sources and to provide a methodology for experimental...
Dr
Roman Pasechnik
(Uppsala University)
23/07/2010, 15:28
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
We present a simple QCD-based model where the soft gluon rescattering between final state partons in deep inelastic scattering leads to events with large rapidity gaps and a leading proton. In the framework of this model the amplitude of the soft gluon exchanges is calculated in the eikonal approximation to all orders in perturbation theory. Both large and small invariant mass M_X limits are...
Aude Gehrmann-De Ridder
(ETH Zurich)
23/07/2010, 16:15
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
All physics reactions at the LHC are initiated by partonic processes, which are determined by QCD. To interpret potential signals and their backgrounds, one thus requires a solid understanding of the QCD dynamics, which is achieved by including higher order perturbative corrections. We review the recent progress on higher order calculations in QCD, focusing on the calculation of multi-leg...
Prof.
Matthias Steinhauser
(KIT)
23/07/2010, 16:35
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
In this talk we consider the production of the Standard Model Higgs boson in the gluon fusion process to NNLO. An approach is presented which allows the calculation of the cross section beyond the heavy-top quark approximation thus leading to results which include the effects of a finite top quark mass. Numerical results are shown for the CERN Large Hadron Collier (LHC).
Prof.
Stefan Dittmaier
(Universitaet Freiburg)
23/07/2010, 16:52
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
The production of t anti-t b anti-b final states represents one of the most important beackground processes for Higgs production in association with top-quark pairs at the LHC. A good background control is indispensible for an analysis of the ttH(->bb) signal, requiring next-to-leading order (NLO) predictions for both signal and background. The talk describes a recently completed NLO QCD...
Roberto Bonciani
(LPSC, Grenoble)
23/07/2010, 17:09
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
We review the status of the theoretical predictions for the top-anti top production in hadronic collisions, paying particular attention to the pair production at the LHC. We stress the need for a complete theoretical analysis that includes higher-order quantum corrections and we discuss recent theoretical calculations at the level of NNLO.
Prof.
Nikolaos Kidonakis
(Kennesaw State University)
23/07/2010, 17:26
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
I present results for the resummation of soft-gluon contributions to QCD hard-scattering cross sections at next-to-next-to-leading logarithm accuracy. A key ingredient is the calculation of two-loop soft anomalous dimensions for the partonic processes. Explicit expressions and applications are provided for processes that involve massless partons and/or massive quarks.
Dr
Konstantin Chetyrkin
(Karlsruhe Institute of Technology (KIT))
23/07/2010, 17:43
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
We report on the first analytical, valid for a generic gauge group, calculations of the O(alpha_s^4) corrections to the Adler function and to DIS sum rules, in particular to the the Gross-Llewellyn Smith and to the Bjorken ones. We discuss a decisive check of correctness of our previous calculations of R(s) in QCD and the quenched QED beta-function at five loops, which was carried...
Thomas Becher
(University of Bern)
24/07/2010, 09:00
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
The production of hard photons in hadronic collisions is studied using Soft-Collinear Effective Theory (SCET). This is the first application of SCET to a physical, observable cross section involving energetic partons in more than two directions. The final resummed inclusive direct photon distribution is valid to next-to-next-to-leading logarithmic order (NNLL), one order beyond previous work....
Juan Terron
(DESY)
24/07/2010, 09:20
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
The production of prompt photons is measured in the photoproduction regime of electron-proton scattering at HERA. Cross sections are measured for photons with transverse momentum and pseudorapidity in the range 6 < Et < 15 GeV and -1.0 < eta < 2.4, respectively. The results are compared with QCD predictions based on the collinear and on the k_T factorisation approaches. The first measurement...
Konstantinos Vellidis
(Fermilab)
24/07/2010, 09:40
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
We report measurements of the direct photon pair production cross section in ppbar collisions at the Fermilab Tevatron Collider using data collected by the CDF and D0 experiments and corresponding to integrated luminosities of 5.3 and 4.2/fb, respectively. Differential cross section measurements are compared with different perturbative QCD predictions, indicating significant disagreements...
Dr
Rong-Shyang Lu
(Physics Department - National Taiwan University (NTU))
24/07/2010, 10:00
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
We present preliminary results on the measurement of isolated photon production cross section in proton-proton collisions at sqrt(s) = 7 TeV, using data collected with the CMS detector. We estimate contribution of background from hadron decays (such as pi0 to two photons) with several variables, including the ratio of momentum measured in the tracker to the energy measured in the...
Junji Tojo
(KEK)
24/07/2010, 10:15
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
Photon identification is important for many physics signatures at the LHC, as well as for detector calibration purposes. Prompt photon identification in ATLAS relies on the fine granularity of the electromagnetic calorimeter, which provides event by event rejection of the dominant background from photons from pi^0 decays, and on the inner detector, which allows us to reconstruct photon...
Gilvan Augusto Alves
(Centro Bras. de Pesquisas Fisicas (CBPF))
24/07/2010, 11:00
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
We review several measurements using data collected by the D0 experiment at the Fermilab Tevatron ppbar collider at sqrt{s}=1.96 TeV and corresponding to an integrated luminosity of 1 fb-1. A sample of photon+3-jet events is used to determine the fraction of events with double parton scattering as a function of the transverse momentum of the second jet. We also report measurements of the...
Christina Mesropian
(Rockefeller University)
24/07/2010, 11:20
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
The CDF Collaboration is working on a systematic study of the underlying event, Minimum Bias events, diffractive processes, and other non-perturbative observables. Such measurements have a two-fold goal of increasing our understanding of soft QCD - mainly through comparison with MC generators - and of reducing the uncertainties on backgrounds for many high-pt analyses. We review the latest...
Dr
Paolo Bartalini
(NTU)
24/07/2010, 11:40
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
Studies of the underlying event and forward processes are important tests of the standard model and inputs for Monte Carlo tuning. By selecting regions transverse and parallel to the hard parton-parton scatter, different aspects of non-peturbative QCD are enhanced and allow fine tuning of different Monte Carlo models. The underlying event in pp interactions, recorded by the CMS detector, is...
1188.
Underlying Event studies and Monte Carlo tunes for inelastic pp events with the ATLAS detector
Emily Nurse
(FNAL)
24/07/2010, 12:05
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
Studies of the momentum flow in inelastic collisions at 900 GeV and 7 TeV recorded with a minimum bias trigger strategy are reported. A single high pT track is selected, and the distribution of other tracks in the event is evaluated relative to this reference track. The evolution of the charged momentum flow in the rest of the event, as a function of the pT of the reference track, gives...
Claudia Glasman
(DESY)
24/07/2010, 14:00
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
Jet Production in ep collisions is presented over the 3 orders of magnitude in Q² and a subsequent determination of alpha_s. A first measurement is presented of the charge asymmetry in the hadronic final state from the hard interaction in DIS neutral current scattering. The production of energetic photons produced at low scattering angles is studied in the DIS case. For the first time,...
Royon Christophe
(DAPNIA)
24/07/2010, 14:30
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
We report on different measurements of jet differential cross section and properties obtained from the analysis of ppbar collisions at the Fermilab Tevatron Collider using data collected by the CDF and D0 experiments. The inclusive jet production cross section is measured with two different jet clustering algorithms, compared with next-to-leading order perturbative predictions using the most...
Tancredi Carli
(CERN)
24/07/2010, 15:00
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
Making use of the excellent calorimetry of the ATLAS experiment, the first measurement of the cross-section for inclusive single-jet and di-jet production in proton-proton interactions at sqrt(s) = 7 TeV will be presented. The corrected and unfolded spectrum for high-pT jets in pp collision at a center-of-mass energy of 7 TeV will be described. Special emphasis will be given to the discussion...
Mikko Voutilainen
(CERN)
24/07/2010, 15:20
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
We report on an extensive list of analyses in order to test QCD predictions for jet production in pp collisions at sqrt(s)=7 TeV, recorded by the CMS experiment. The list includes a measurement of the inclusive jet spectra, obtained with different jet reconstruction methods, the ratio of the inclusive three-jet over two-jet cross sections as a function of the total jet transverse momentum HT,...
David Kosower
24/07/2010, 16:15
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
We compute the NLO QCD corrections for the production of a weak vector boson (W or Z) in association with up to three jets at the LHC, using the programs BlackHat and SHERPA. We study total cross sections as well as distributions. We discuss W polarization phenomena. We also present a study of ratios between related processes, which could enable data-driven background estimations,...
Dr
Avto Kharchilava
(SUNY at Buffalo)
24/07/2010, 16:40
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
We present several measurements of the differential cross sections for W and Z bosons produced in association with jet(s), using data samples corresponding to integrated luminosities between 1 and 5.4/fb of ppbar collisions collected with the D0 detector. We present differential cross section measurements for Z/gamma*+jet+X relative to the Z\gamma* transverse momentum, relative to the leading...
Stefano Camarda
(IFAE Barcelona)
24/07/2010, 17:05
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
The CDF Collaboration has a comprehensive program of studying the production of vector bosons, W and Z, in association with energetic jets. Excellent understanding of the standard model W/Z+jets and W/Z+c,b-jets processes is of paramount importance for the top quark physics and for the Higgs boson and many new physics searches.
We review the latest CDF results on Z-boson production in...
Dr
Burkard Reisert
(Max-Planck-Institute for Physic, Munich)
24/07/2010, 17:30
03 - Perturbative QCD, Jets and Diffractive Physics
Parallel Session Talk
A measurement of the inclusive deep inelastic neutral current e+ p scattering cross section is reported in the region of four-momentum transfer squared, 12 GeV^2<Q^2<150 GeV^2, and Bjorken x, 2 times 10^-4<x<0.1. The results are based on data collected by the H1 Collaboration at the ep collider HERA at positron and proton beam energies of E e = 27.6 GeV and Ep = 920GeV, respectively. The data...
