QCDIPPP June 2006 Kaidalov Bashir Ryskin Khoze Pennington
QCD@IPPP June 2006
Kaidalov Bashir Ryskin Khoze Pennington Diffraction Papagallo Ball Martin Roberts Stirling Partons Hadrons Zwicky QCD Twistor Space Khoze Georgiou Glover De Roeck Huston Cross sections Richardson Will discuss in future Monte Carlo Krauss open session Hamilton Grellscheid Resummation Maxwell Van Acoleyen Vogt Brein Buckley Figy Signer Stockinger
Martin, Stirling + Roberts, Thorne MRST Parton distributions 1. Uncertainties on partons I: experimental errors Uncertainties due to errors on experimental data fitted obtained using both the Hessian and Lagrange multiplier approaches. Examples: resulting errors on predictions for W, Higgs prod. , and CC DIS 2. Uncertainties on partons II: theoretical errors Uncertainties due to NLO NNLO, ln(1/x) and ln(1 -x) effects, absorptive corrections, higher twist, choice of input parametrization, isospin violation….
Martin, Stirling + Roberts, Thorne MRST Parton distributions 3. Physical gluons and high ET jets Physical large x parametrization of gluon --driven by valence quarks in MSbar scheme --gives excellent description of Tevatron jets
Martin, Stirling + Roberts, Thorne MRST Parton distributions 4. Parton distributions incorporating QED contributions Includes a. QED contributions: treats photon as a parton. Automatically includes isospin violation explains 50% of Nu. Te. V anomaly Fewer high x up than dn, since more photons emitted from u. Proton PDFs Neutron PDFs
Martin, Stirling + Roberts, Thorne MRST Parton distributions 5. The role of FL(x, Q 2) in parton analyses Motivated by the forthcoming measurements of FL at HERA -- NNLO analysis gives better description at low x -- some evidence of higher twist contributions 6. MRST partons generated in a fixed flavour scheme Needed for existing Monte Carlos and other calculations in FFNS.
Martin, Stirling + Roberts, Thorne MRST Parton distributions Personnel changes Dick Roberts has retired, and Graeme Watt (UCL) has joined the collab. Future studies Complete NNLO analysis including all recent data in VFNS, and providing quantitative errors on partons With Misha Ryskin and Graeme Watt (UCL) : 1. Determination of diffractive parton densities applying our novel p. QCD approach to the new diffractive data. 2. Determination of the structure of the pion by extending our analysis of the HERA leading neutron data.
Ball, Zwicky From Inclusive to Exclusive Processes • Parton distributions: One particle probability amplitudes • Multiparton Distributions: Correlations and interference effects
Ball, Zwicky From Inclusive to Exclusive Processes Concept: Light-cone distribution amplitudes Particle wave functions at small transverse separation b~1/Q: üPartial-wave expansion using conformal symmetry of massless QCD üAnalysis of higher twist effects using QCD equations of motion üApplications: EM form factors, photon transition form factors, nonleptonic B decays…
Khoze, Martin, Stirling + de Roeck, Kaidalov, Ryskin Diffractive processes as a means to study new physics at the LHC Ø theoretical motivation behind the recent proposals to add the Forward Proton taggers to the LHC experiments Ø the basic ingredients of Durham approach through the eyes of existing Tevatron and HERA diffractive data Ø direct engagement with experimentalists in analysing and planning the forward measurements, in part. , FP 420 R&D.
Khoze, Martin, Stirling + de Roeck, Kaidalov, Ryskin Diffractive processes as a means to study new physics at the LHC Main advantages of CED Higgs production ü Accurate mass measurement (irrespective of the decay mode). ü Quantum number filter/analyser. (0++ dominance ; CP-even) ü H ->bb not swamped by background ü H →WW*/WW ( ) less challenging experimentally Theoretical challenges : Ø need for developed and well tested models for soft diffraction Ø unusually & uncomfortably large higher-order QCD effects (e. g. Sudakov. and non. Sudakov Logs… ). Ø no suitable conventional analytic or MC results readily available (colour singlet, Jz=0)
Khoze, Martin, Stirling + de Roeck, Kaidalov, Ryskin Diffractive processes at the tevatron CDF
Heinemeyer, Khoze, Ryskin, Stirling, Tasevsky, Weiglein Diffractive processes as a means to study new physics at the LHC PRELIMINARY
Khoze, Stirling + de Roeck The FP 420 R+D project üClose ties with Manchester and other UK FP 420 members. üSuccessful annual IPPP Manchester Forward workshops (from 2001) üJoint research and publications. The LHCC acknowledges the scientific merit of the FP 420 physics program and the interest in exploring its feasibility - LHCC The panel believes that this offers a unique opportunity to extend the potential of the LHC and has the potential to give high scientific return. - PPARC PPRP
Glover, Anastasiou, Garland, Koukoutsakis, Tejeda-Yeomans, + Heinrich, Gehrmann-De Ridder, Remiddi NNLO Jets in e+eüTwo loop matrix elements computed some time ago üAntenna subtraction scheme to isolate infrared divergences üAnalytic integration of infrared poles üAnalytic cancellation of infrared poles üNumerical implementation now in progress
Glover + Gehrmann, Gehrmann-De Ridder, Heinrich NNLO Jets in e+e- T dσ σ d. T Other colour factors in progress, expected later this year
Glover, Pires NNLO Jets in pp üNeeded for better determinations of PDF’s and αs üNLO accuracy at best ± 30% üNNLO accuracy ~10% üUsing sector decomposition to extract phase space singularities üAim to have first results by start of LHC
Signer + Pineda Threshold resummation for heavy quarks ü At threshold there are two small parameters αs and v ü Also several scales m, mv and mv 2 ü ln(v) large and must be resummed ü Complete result at NLL and including some NNLL terms
Dinsdale, Maxwell Infrared resummation ü Extended effective charge scheme to include resummation of infrared logarithms ü Size of fitted power correction C 1/Q varies with order, but more stable extraction of ΛMS C 1/Q Thrust
Pennington, Boglione, Edera, Fischer, Papagallo, Williams + Bashir Hadrons and confinement ü Hadron spectrum ü Chiral symmetry breaking ü Dynamical mass generation ü Confinement ü Dyson-Schwinger equations hep-ph/0504262
Pennington, Boglione γγ π+ π- and π0 π0 Couplings probe hadron dynamics peak hep-ph/0504262 dip Mark II
Many other activities Infrared finite amplitudes LHC MSSM cross sections Non-perturbative vertices with SDE Finite volume effects in quenched lattice GT Isospin effects in D decay DRED v DREG for SUSY One-loop multi-leg processes Higgs cross sections NNLO splitting functions/coefficient functions Twistor phenomenology Signer, Brown Brein Pennington, Bashir, Williams Pennington, Fischer Pennington, Edera Signer, Stockinger Glover, Badger Figy Vogt Ozeren, Georgiou, Badger, Khoze, Glover, Stirling
QCD related Ph. D Theses Tejeda-Yeomans (01) Parton-Parton Scattering at Two-Loops Kimber (01) Unintegrated Parton Distributions Anastasiou (01) Two-Loop integrals and QCD scattering Andersen (02) Monte Carlo Studies of BFKL Physics Adamson (02) Vector boson pair production at hadron colliders Williams (02) Hadronic Higgs Production with Forward Jets Koukoutsakis (03) Higgs Bosons and QCD Jets at Two Loops Garland (03) Two-loop helicity amplitudes in QCD Watt (04) Parton Distributions Howe (04) Infrared Behaviour of QCD Observables Forde (04) Infrared Finite Amplitudes Morley-Fletcher (05) Covariant infrared finite amplitudes Dinsdale (05) The scheme-dependence of power correction fits to event shape observables Birthwright (05) Two loop vertices and tree level multicollinear limits in QCD http: //www. ippp. dur. ac. uk/Research/theses. htm
QCD related workshops 18 workshops/schools including Ø Ø Ø Ø 5 x Manchester forward physics workshops 57 th SUSSP school on LHC Phenomenology Light-Cone Physics: Hadrons and Beyond (Swansea) Multiparticle Production in QCD Jets Workshop on Te. V-Scale Physics (Cambridge) Monte Carlos at Hadron Colliders Future Physics at HERA QCD related PDRA’s Carlo Oleari, Zoltan Nagy, Elena Boglione, Gudrun Heinrich, Giulia Zanderighi, Gabriele Travaglini, Peter Marquard, Dominik Stockinger, Christian Fischer, Karel Van Acoleyen, Oliver Brein, Terrance Figy, Laura Edera, Fulvia de Fazio, …
…and finally • Advancing Collider Physics from Twistors to Monte Carlos • Aug 27 -Oct 26 2007
Khoze, Martin, Stirling + de Roeck, Kaidalov, Ryskin Diffractive processes: the next steps üComprehensive study of the radiative backgrounds to the H->bb CEDP, application to the Higgs physics at PC@ILC. üLeading neutron spectra at HERA as a way to gauge the absorptive effects and enhanced Pomeron contributions üDetailed investigation of the BSM Higgs sector in diffractive processes ü Study of the NLL- effects in the mass-suppressed Jz=0 gg/ -> qq amplitudes
Khoze, Martin, Stirling + de Roeck, Kaidalov, Ryskin Diffractive processes: the mid-term 1. Very Optimistic scenario: FP-420 is approved, and Higgs is found at the LHC. work needed to improve the accuracy of calculations to match experimental precision 2. FP 420 - unfriendly scenario: Higgs is found, but FP-420 is not approved or long delayed. application of the ‘event colour portrait’ technique to disentangle the Higgs signal from the QCD backgrounds. 3. Pessimistic scenario: Elementary Higgs is not found and FP-420 is not approved. Comprehensive soft and semi-soft physics programs for TOTEM, CMS-TOTEM and ATLAS (possibly ALICE). Photon-induced interactions at the LHC.
- Slides: 27
