Report

HSQCD 2004 DGLAP BFKL DPP GLR Alan Martin (Durham) Repino, St. Petersburg 18-22 May, 2004 Klempt Glueballs, hybrids, pentaquarks not a glueball Klempt Pentaquarks Several expts see an exotic B=1, S=1 baryon resonance in K+n or K0p channel Qs(1530) with narrow width G<10 MeV The chiral soliton model (cSM) predicted Qs(1530) with G<15 MeV, JP=(1/2)+ in a 10 of SU(3)f Praszalowicz(1987), Diakonov,Petrov,Polyakov(1997) Qs(1530) seen by many expts in K+n, K0p N S X-NA49 see X(1860) which is not seen by ZEUS & WA89 X Popov HERMES Hyarapetian but is Qs(1530) seen by H1 ?? Kubantsev 1.5 MeV now expected from cSM --- Petrov Petrov Bag model fails for Q+(uudds) Need new degree of freedom: diquark ? -------CQM Jaffe-Wilczek (ud)2 s Karliner-Lipkin (ud)(uds) …..but needs diquark in P-wave, many problems, always predicts too heavy Q+ e.g. Narodetskii p is lightest degree of freedom ----- cSM Polyakov is the N*(1710) in the 10 ? considers mixing with octet gpp* / gnn* ~ 0 by U-spin G(N*) ~ 10-20 MeV Qs(1530) pN 2 MeV pD 5 MeV hN 3 MeV N S X pN PWA: N* could be P11(1680 or 1730) Petrov considers mixing with the Roper octet Klempt 1577 ? cSM predicts 27 with I=1 KN multiplet -- but K+p partner not seen Buschhorn H1 see Qc which is not seen by ZEUS ? bb prod: latest data and theory in satisfactory agreement Hadron spectroscopy is on the boil. Changes almost daily. Very exciting and experimentally confusing. Rostovsev low x Fixed target DIS ep, ed, nN; D-Yan, W asym, Tevatron jets HERA ep global DGLAP parton analyses CTEQ, MRST analyses to selected data sets Botje, Alekhin, ZEUS, H1… Expect small x processes to be driven by the gluon. Surprise at v.low scales appear to be dominated by by singlet sea quarks valence-like or -ve gluon ! Sea quarks & gluons not (perturbatively) connected. x F2 versus x 1993 (Lum=20 nb-1) Now BFKL confinement Regge ln 1/x DGLAP ln Q2 HERA has opened up the small x domain • how large is the DGLAP domain ? • are BFKL (log 1/x) effects evident ? • is there any evidence of absorptive corrections, or even parton saturation ? • HERA observes diffractive DIS (at ~10% of DIS). What role does it play ? • what would we like HERA to measure now ? CTEQ gluon Q2=5 compared to MRST error band Q2=100 Parton uncertainties due to stat/sym errors of data fitted Other uncertainties include selection of data fitted; choice of x,Q2,W2 cuts Kotikov Theoretical uncertainties higher-order DGLAP NLO, NNLO…Moch,Vermaseren,Vogt asln(1/x) and asln(1-x) effects absorptive corrections from parton recombination residual higher-twist effects QED effects Uncertainties due to input assumptions isospin-violating effects MRST s not equal to s CTEQ heavy-target corrections choice of input parametrization no NuTeV sin2q anomaly Alwall MRST NNLO suggests W or Z prod. can be be used as a luminosity monitor at the Tevatron (& LHC) Kataev IG = = Gottfried sum rule in the large Nc limit (dx/x) (F2mp – F2mn) = 0.235 +/- 0.026 expt. 1/3 - 2/3 valence: pert. corr. small, higher twist small as/Nc2 dx (d – u) non-pert asymmetry of sea. what happens as x0? (cSM) (i)checks from Adler SR. (ii) 3-loop anom. dim. of MVV (NNLO) confirms colour structure Experimental ways to determine the gluon • FL most direct x ~ 10-4 - 10-3 • Prompt photon data (WA70,E706) and theory problems • Tevatron jets x ~ 0.07 – 0.5 • HERA jets (ZEUS) x ~ 0.01 - 0.1 • Diffractive J/y at HERA g2 (+ momentum sum rule) x ~ 10-3 need to improve theory Inclusive jets Zeitnitz Top quark cross section Run I Run II Savin & Rostovtsev inclusive jet helps pin down gluon at x~0.1 3 jets/2 jets FL Q2=10 Q2=5 Extremely valuable if HERA could measure FL with sufficient precision --- to pin down the low x gluon Data are Klein’s simulation based on runs at Ep = 400,465,575,920 GeV. Q2=20 Thorne Q2=40 Stirling Higgs DGLAP ln 1/x resum ? abs. corr. ? Lipatov What happens to the Pomeron traj. at high temp.? Remarkably -- nothing happens for fixed as. -- result of conformal inv. of the original theory. Running as destroys inv. – no exact solution – expect some change May be possible to establish relation between BFKL and string dynamics – dimensions of space-time = no. of t ch. gluons? Gluon kt distribution in resummed NLL BFKL Gluon kt along evolution chain --- find that NLL BFKL and DGLAP v.similar Important since underlying event might have masked New Physics signals at LHC. Ryskin Final kt=30 GeV at y=ln(1/x)=8 LO BFKL DGLAP, DLLA NLL BFKL y=4 Monte Carlos OK y=6 y=2 Diffractive DIS data Mastroberardino Schildknecht: Also describes F2, F2D, vector meson prod. well, using dipole approach with GVMD, incorporating saturation Original Golec-Biernat, Wusthoff fit Include charm. Relate to xg & evolve in Q2 +Bartels,Kowalski Is it saturation or confinement ? mq=0 mq=140 MeV There are other dipole fits without saturation e.g. Forshaw, Kerley & Shaw. Saturation No definitive experimental evidence Much theoretical activity ----BK, JIMWLK,…equations A glimpse… Rostovsev Equivalent approaches p rest frame / fast dipole fast p / slow dipole bare dipole g wave fn. evolved p wave fn. (cgc) Balitsky Kovchegov eq. Lublinsky explained this much better leads to Jalilan Marian, Iancu, McLerran, Weigert, Leonidov, Kovner eq. Two progress reports: Fadin is proving that gluon Reggeization is valid at NLO BFKL Checking the consistency of bootstrap relations, s ch. unitarity and Reggeization for production amplitudes. Bartels is relating the BK equation to Reggeon field theory Remarkable simplifications from Mobius invariance Saturation momentum Qs(x) in NLL BFKL ~ DGLAP Qs Ryskin 2 LO BFKL unreliable, BK,JIMWLK eqs. ?! x0/x x0 defined by Qs(x0)=1 GeV Nikolaev Saturation effects in nuclei. Diffractive DIS is about 50% in nuclei. Collective nuclear glue (nuclear Pomeron) is a good idea but destroys kT factorization. Also fan diagrams no longer sufficient. Diffractive DIS data Mastroberardino Mastroberardino Mastroberardino Mastroberardino ln Q2 higher twist Bartels,Ellis, Kowalski & Wusthoff base parametrization on these forms Contribution of diffractive F2 to inclusive F2 Apply the AGK cutting rules to Ryskin contrib. AGK in QCD: Bartels & Ryskin Im Tel ~ stot DF2abs ~ - F2D In pQCD, negative is a cut, not a pole (~Glauber shadowing) Lipatov has a continuous no. of compts of different size, r~1/m For each compt., DGLAP evol. of F2D(x,Q2,m2) starts from m Q provided it is large enough Ryskin Ryskin Input ~ MRST2001 Ryskin Ryskin xg, xS const Need Q2 Q2+1 mimics power corr. rapidity gap survival factor S2 ~ 0.1 HERA g* Survival factors calc. from 2-ch eikonal model based on multi-Pom. exchange & s channel unitarity KKMR S2 ~ 1 Mastroberardino Diffractive photoproduction of dijets: direct compt. S2 ~ 1 resolved compt. (hadron-like) S2 ~ 0.34 NLO analysis by Klasen & Kramer,-good agreement with prelim. H1 data Note in LO analysis, data would prefer S2 ~ 1 for resolved Exclusive diffractive Higgs signal pp p+H+p Khoze Advantages: 2 indep. MH det. 1. missing mass to proton taggers (DM~1 GeV) 2. bb decay (DM~10 GeV) Higgs S2 = 0.026 bb backgd v.suppressed by Jz=0 selection rule For a 120 GeV (SM) Higgs at the LHC (L=30 fb-1) 11 events / 4 background For MSSM with tanb~50, mA~130 GeV 70 events / 3 background Khoze 5s signal at LHC 30 fb-1 300 fb-1 Kim, Schlein Higgs via single Pomeron exchange Predicted much larger signal, but ---need to study of background, ---include evolution from Q2=50 GeV2 (UA8) up to Q2=104 GeV2 Amarian Semi-inclusive ep epX HERMES Sidorov Sidorov Ochs Ng/Nq = CF/CA = 9/4 -- naïve MLLA -- better agreement with e+e- data Full calculation – excellent agreement L parameter determined from multiplicity Pivovarov Calculated the B parameter at NLO --- three loop non-factorising massive Feynman graph B = 1 + 0.095 - 0.05 pert. nonpert. Apologies omitting for so many excellent contributions There are so many crucial measurements still to be done, and unless the correct action is set into motion soon, time will run out for HERA --while the physics potential of the machine is still coming to its prime. Buschhorn Very special thanks to Petersburg Nuclear Physics Institute Petersburg branch of the RAS Petersburg State University Fock Institute of Physics Staff of the Baltiets Hotel Assistants Pavel Yakimov Julia Grebenyuk Nastya Grebenyuk Sergey Anufriev Sergey Afonin Photographer Tatiana Potapova Foreign department Tatiana Bondarenko Natalia Nikitina Drivers Sergey Zvonovsky Eduard Patsyukov Dima Dzyubchuk Social Programme Lyudmila Kolesnikova Victor Gordeev Victor Kim Lev Lipatov Secretariat Galina Stepanova Zoya Gaditskaya Lidia Rusinova Tatiana Gordeeva …and to ALL the participants for making this such a productive and enjoyable meeting …and so on to HSQCD 2005