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 VII Latin American Symposium on High Energy Physics IX Argentinian Symposium of Particles and Fields San Carlos de Bariloche January 2009

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 Motivations VII Latin American Symposium on High Energy Physics IX Argentinian Symposium of Particles and Fields San Carlos de Bariloche Jan 2009 H1 Collaboration

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

Diffractive DIS at HERA Inclusive DIS: Probes partonic structure of the proton Diffractive DIS: Probes structure of the exchanged color singlet X X Q 2 : 4-momentum exchange W: p center of mass energy x: fraction of p momentum carried by struck quark x IP : fraction of p momentum carried by the Pomeron (IP) β: fraction of IP momentum carried by struck quark 1 VII Latin American Symposium on High Energy Physics IX Argentinian Symposium of Particles and Fields San Carlos de Bariloche Jan INGELMAN, G.; SCHLEIN, P. E. Phys. Lett. B 152, 256 (1985)

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 x a and x b are the momentum fractions of nucleons carried by the partons f i/h is the parton distribution function (PDF) of a parton of flavor i = a,b in the hadron h = A, B 2 COOPER, F. et al PRL 93 (2004) VII Latin American Symposium on High Energy Physics IX Argentinian Symposium of Particles and Fields San Carlos de Bariloche Jan 2009 Y, P

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

Partial decay width Γ cc = e c 2 =4/9; M ψ = GeV; α s = g s 2 / 4π, m c = 1.5 GeV, To ϒ case m c m b ; M ψ M Y ;m b = 4.5 GeV, M Υ = 9.46 GeV; Γ bb = Singlet cross sections 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 Jan LANSBERG, J. P., Int. J. Mod. Phys. A 21, 3857 (2006)

Gap Survival Probability (GSP)‏ 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 A(s,b) is the amplitude (in the parameter space) of the particular process of interest at center-of-mass energy P S (s,b) is the probability that no inelastic interactions occur between hadrons scattered 6 MACHADO, M. M., GAY DUCATI, M. B. MACHADO, M. V. T. PRD 75, (2007)‏ 8 CHEHIME, H. et al PLB 286, 392 (1992) 7 BJORKEN, J. D. PRD 47, 101 (1992) VII Latin American Symposium on High Energy Physics IX Argentinian Symposium of Particles and Fields San Carlos de Bariloche Jan 2009

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) KMR models GSP KMR multiple channels 9 Khoze-Martin-Ryskin Eur. Phys. J. C (2002) R J/ψ LHC (%)R J/ψ Tevatron (%) central forward VII Latin American Symposium on High Energy Physics IX Argentinian Symposium of Particles and Fields San Carlos de Bariloche Jan 2009 R Y Tevatron (%)

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

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

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

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 Jan 2009