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Diffractive Quarkonium Production at High Energies

Diffractive Quarkonium Production at High Energies. Mairon Melo Machado a , Maria Beatriz Gay Ducati a , Magno Valério Trindade Machado b High Energy Phenomenology Group, GFPAE a IF – UFRGS, Porto Alegre,~Rio Grande do Sul b UNIPAMPA, Bagé, Rio Grande do Sul melo.machado@ufrgs.br

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Diffractive Quarkonium Production at High Energies

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  1. Diffractive Quarkonium Production at High Energies Mairon Melo Machadoa, Maria Beatriz Gay Ducatia, Magno Valério Trindade Machadob High Energy Phenomenology Group, GFPAE aIF – UFRGS, Porto Alegre,~Rio Grande do Sul bUNIPAMPA, Bagé, Rio Grande do Sul melo.machado@ufrgs.br www.if.ufrgs.br/gfpae VII Latin American Symposium on High Energy Physics IX Argentinian Symposium of Particles and Fields San Carlos de Bariloche 14-21 January 2009

  2. Motivations • Study of inclusive and diffractive cross sections • Pomeron plays a particular and very important role in soft process at high energy strong interaction • Study of heavy quarkonium production mechanism • Study the nature of Pomeron in the QCD framework • Investigation of the effects from multiple Pomeron scattering • gap survival probability factor • Analysis using recent parametrization for Pomeron structure function H1 Collaboration VII Latin American Symposium on High Energy Physics IX Argentinian Symposium of Particles and Fields San Carlos de Bariloche 14-21 Jan 2009

  3. Diffractive Process • Rapidity (y) gaps no particle production • Hadron-hadron collisions 1% • Pomeron carries the quantum numbers of the vacuum pz proton momentum • Measured also at HERA (DESY) collider (H1 and Zeus Collaboration)‏ • DDIS contributes substantially to the cross section 10% of visible low-x events VII Latin American Symposium on High Energy Physics IX Argentinian Symposium of Particles and Fields San Carlos de Bariloche 14-21 Jan 2009

  4. DiffractiveDIS at HERA Inclusive DIS: Probes partonic structure of the proton • Q2: 4-momentum exchange • W: p center of mass energy • x: fraction of p momentum carried • by struck quark • xIP: fraction of p momentum carried • by the Pomeron (IP) • β: fraction of IP momentum carried • by struck quark X Diffractive DIS: Probes structure of the exchanged color singlet 1 X 1 INGELMAN, G.; SCHLEIN, P. E. Phys. Lett. B 152, 256 (1985) VII Latin American Symposium on High Energy Physics IX Argentinian Symposium of Particles and Fields San Carlos de Bariloche 14-21 Jan 2009

  5. Inclusive process • Cross section for process in which partons of two hadrons (A and B) interact producing associated J/ψ+γ (ϒ+γ)final states • xa and xb are the momentum fractions of nucleons carried by the partons • fi/h is the parton distribution function (PDF) of a parton of flavor i = a,b in the hadron h = A, B Y, P 2 COOPER, F. et al PRL 93 (2004) 171801 VII Latin American Symposium on High Energy Physics IX Argentinian Symposium of Particles and Fields San Carlos de Bariloche 14-21 Jan 2009

  6. J/ψ Diffractive cross sections 3 XU, J. S. AND PENG, H. A.. PRD 59 (1999) 014028 • PT distributions of leptons in J/ψ ( ϒ ) diffractive cross section Y, P • fg/IP is the gluon distribution in the Pomeron - experimental parametrization to Pomeron structure function (H1) and fIP/p is the Pomeron flux VII Latin American Symposium on High Energy Physics IX Argentinian Symposium of Particles and Fields San Carlos de Bariloche 14-21 Jan 2009

  7. Singlet cross sections • Partial decay width Γcc = 0.05084 • ec2=4/9;Mψ = 3.096 GeV; αs = gs2 / 4π, mc = 1.5 GeV, • To ϒ case mc mb; Mψ MY;mb = 4.5 GeV, MΥ = 9.46 GeV; • Γbb= 0.0294 4 LANSBERG, J. P., Int. J. Mod. Phys. A 21, 3857 (2006) 5 KIM, C. S., et. al.Phys.Rev. D55 (1997) 5429 VII Latin American Symposium on High Energy Physics IX Argentinian Symposium of Particles and Fields San Carlos de Bariloche 14-21 Jan 2009

  8. Gap Survival Probability (GSP)‏ 6 MACHADO, M. M., GAY DUCATI, M. B. MACHADO, M. V. T. PRD 75, 11403 (2007)‏ • Currently a subject of intense theoretical and experimental research • GAP region of angular phase space devoid of particles • Survival probability fulfilling of gap by hadrons produced in interactions of remanescent particles 7 BJORKEN, J. D. PRD 47, 101 (1992) 8 CHEHIME, H. et al PLB 286, 392 (1992) • A(s,b) is the amplitude (in the parameter space) of the particular process of interest at center-of-mass energy • PS(s,b) is the probability that no inelastic interactions occur between hadrons scattered VII Latin American Symposium on High Energy Physics IX Argentinian Symposium of Particles and Fields San Carlos de Bariloche 14-21 Jan 2009

  9. RJ/ψ Tevatron (%) RJ/ψ LHC (%) 0.48 0.15 0.28 0.09 KMR models • GSP KMR multiple channels • pion-loop insertions in the Pomeron trajectory • non-exponential form of the proton-Pomeron vertex  (t) • absorptive corrections, associated with eikonalization • values of GSP 0.15 (0.09) Tevatron (LHC) 9 Khoze-Martin-Ryskin Eur. Phys. J. C. 26 229 (2002) central forward VII Latin American Symposium on High Energy Physics IX Argentinian Symposium of Particles and Fields San Carlos de Bariloche 14-21 Jan 2009

  10. Results for J/ψ • Color-octet is predominant to high pt VII Latin American Symposium on High Energy Physics IX Argentinian Symposium of Particles and Fields San Carlos de Bariloche 14-21 Jan 2009

  11. * This work Ref 2 R Tevatron (%) 0.37 0.38 R LHC (%) 0.12 - Results for J/ψ without GPS R LHC = 0.42% R Tevatron = 0.61% • J/ψ production is dominated by gluon-gluon fusion * Average of pseudo-rapidity (central and forward) VII Latin American Symposium on High Energy Physics IX Argentinian Symposium of Particles and Fields San Carlos de Bariloche 14-21 Jan 2009

  12. Results for ϒ 10 Rybarska, A. et al Phys. Lett. B 660, 126 (2008)‏ Contribution of ϒ is smaller than J/ψ contribution VII Latin American Symposium on High Energy Physics IX Argentinian Symposium of Particles and Fields San Carlos de Bariloche 14-21 Jan 2009

  13. Conclusions • Calculation of J/ψ ( ϒ )diffractive hadroproduction process and momentum distributions of produced photon • Using new Pomeron diffractive parton distributions (H1 Collaboration – DESY – HERA) and theoretical estimate for GSP • Ratio diffractive/inclusive cross section falls using GSP • Agreement with another phenomenological prediction of 3, 4 • Application of Gap Survival Probability should be made • Useful observable to test future extractions of Pomeron PDF’s • J/ψ production dominates at high energies high partial decay • Color-Octet contributions will be included in next work VII Latin American Symposium on High Energy Physics IX Argentinian Symposium of Particles and Fields San Carlos de Bariloche 14-21 Jan 2009

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