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ROLE OF GLUONS in SOFT and SEMI-HARD P-P COLLISIONS AT LHC. Gennady Lykasov*, Vadim Bednyakov * , Andrey Grinyuk * , Martin Poghosyan ** *JINR, Dubna, **CERN. June 2011. 1. OUTLINE. 1. Gluon distribution in proton 2. Quark –Gluon-String Model ( QGSM ) and gluons
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ROLE OF GLUONS in SOFT and SEMI-HARD P-P COLLISIONS AT LHC Gennady Lykasov*, Vadim Bednyakov*, Andrey Grinyuk*, Martin Poghosyan** *JINR, Dubna, **CERN June 2011 1
OUTLINE 1. Gluon distribution in proton 2. Quark –Gluon-String Model (QGSM) and gluons in proton. 3. Inclusive spectra of charge hadrons in p-p within QGSM including gluons 4. Elastic parton-parton scattering and semi-hard p-p collisions 5. Summary June 2011 2
UN-INTEGRATED GLUON DISTRIBUTION IN PROTON where R0=C1(x/x0)λ/2 K.Golec-Biernat & M.Wuesthoff, Phys.Rev. D60, 114023 (1999) H.Jung, hep-ph/0411287, Proc. DIS'2004 Strbske Pleco, Slovakia June 2011 4
DIAGRAMS in ppcollisions within QGSM Fig. 1. The one-cylinder graph (at the left) and the multi-cylinder graph (at the right) for the inclusive pp hX process. Fig.2. One-Pomeron exchange (left) and the cut one-Pomeron exchange (right); P-proton, g-gluon, h-hadron produced in PP June 2011 5
Inclusive hadron production in central region and the AGK cancellation V.A.Bednyakov, A.A.Grinyuk, G.L., M.Poghosyan, hep-ph/0224591 (2011). June2011 6
Parton - parton interactions within LO QCD, the wavy line is the gluon, the solid line is the quark. February 2011, JINR 7
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The inclusive spectrum of charge hadrons in p-p at y=0. The gluon distribution at low transverse momenta was calculated and the parameters were found to describe the LHC data satisfactorily. V.A.Bednyakov,A.A.Grinyuk,G.I.Lykasov, M.G.Poghosyan, hep-ph/0224591 (2011); June2011 9
The unintegrated gluon distribution at x = 10-4 Hannes Jung, hep-ph/0411287, 2004. June2011 10
SUMMARY The soft QCD or the QGSM describes the experimental data on inclusive spectra of charge hadrons produced in p-p at low pt (< 1 GeV) rather satisfactorily The inclusion of the gluon distributions in proton allows us to apply the QGSM to analyze the hadron production in p-p at higher transverse momenta (~ 2 GeV) Starting from ~ 2 GeV hard processes dominate: Field, Feynman, Fox model and perturbative QCD. The unintegrated gluon distributions in proton at low intrinsic transverse momenta were calculated and parameters were found fitting the LHC data. At large intrinsic transverse momenta they should coincide to the distributions found by GBW, J.Hannes and others.
THANK YOU VERY MUCH FOR YOUR ATTENTION ! We also thank A.Bakulev, V.Cavasini, A.Dorokhov, A.V.Efremov, F.Francavilla, C.Gwenlan, H.Jung, V.Kim, N.Kochelev, E.A.Kuraev, LN.Lipatov, T.Lomtadze, M.Mangano, C.Merino, S,V.Mikhailov, E.Nurse, F.Palla, E.Pilkington, A.F.Pikelner, C.Royon, M.G.Ryskin, E.Sarkisyan-Grinbaum, O.V.Teryaev, Yu.Shabelski and V.V. Uzhinskiy for very useful discussions and comments. June 2011 12
Aq = 11.91 ± 0.39, bq = 7.29 ± 0.11 Ag = 3.76 ± 0.13 bg = 3.51 ± 0.02 So, the inclusive spectrum is presented in the following form: June2011 15
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