Quarkonium Production at J-PARC Jen-Chieh Peng University of Illinois at Urbana-Champaign J-PARC Meeting for Spin and Hadron Physics RIKEN, April 7-8, 008 Outline Quarkonium Production at J-PARC with Unpolarized Proton Beam Quarkonium Production at J-PARC with Polarized Beam and Target Calculations of charm and J/Ψ production from Yuan Feng 1
Physics with quarkonium production at J-PARC J / Ψ production with unpolarized proton beam: J / Ψ production mechanism at J-PARC energies -- is it dominated by quark-antiquark annihilation or gluon-gluon fusion? Nuclear dependence of J / Ψ production Antiquark distributions in nucleons and nuclei Polarization of J / Ψ and Ψ J / Ψ Production with polarized beam/target: Sivers quark distribution with single-spin asymmetry AN Sea-quark polarization with double-spin asymmetry ALL Quark transversity distributions with double-spin asymmetry A TT
J/Ψ Production at J-PARC Energies Very few data for J/Ψ production at 30-50 GeV 4 GeV/c at CERN-PS 70 GeV/c at IHEP Schub et al., Fermilab E789, PR D5 (1995) 1307 σ B τ ( + / Ψ+ ) = ; where τ = / p N J x Ae M s 3
Color-Evaporation Model for J/Ψ Production dσ dx J ψ = F τdτ H ( x, x ; m )/( x + 4 τ ) wher / ( / ) F τ1 = s and x = x x e τ m / τ F PT 1 1 1/ F CEM calculations versus data τ : QQ threshold, 1 τ : open charm threshold H PT ( x, x 1 1 ; m ) G ( x ) G ( x ) σ ( gg QQ; m P T + + Gluon-gluon fusion = i i i i { qp( x1) qt( x) qp( x1) qt( x)} σ ( qq QQ; m ) i= u, d, s ) Quark-antiquark annihilation Schuler, Vogt, PL B 387(1996)181 4
J/Ψ Production at 30 GeV At 800 GeV, J/Ψ production is dominated by gluon-gluon fusion At 30 GeV J/Ψ production is dominated by quark-antiquark annihilation J/Ψ production at 30 GeV is sensitive to quark and antiquark distributions 5
Counts/0.1 GeV/c Evidence that gluon-gluon fusion is the dominant mechanism at 800 GeV 800 GeV σ( p + d μ + μ X ) / σ( p + p μ + μ X ) 10 5 10 4 10 3 10 10 1 J/ψ ψ 4 6 8 10 1 14 16 Mass (GeV/c ) pd Drell J ϒ / Ψϒ, : ϒ ϒ Yan: σ σ pd σ pd /σ pp 1.3 1. 1.1 1 0.9 0.8 0.7 FNAL E866/NuSea Drell-Yan Drell-Yan J/ψ ϒ(1S) ϒ(S) MRST CTEQ4M CTEQ5M CTEQ4M (d _ - u _ = 0) 1% Systematic error not shown GRV98 0.6 0 0.05 0.1 0.15 0. 0.5 0.3 0.35 pp 1 / σ [1 + d( x)/ u( x)] pp 1 / σ [1 + g ( x)/ g ( x)] n x p 6
Evidence that gluon-gluon fusion is the dominant mechanism at 800 GeV 800 GeV σ( p + d μ + μ X ) / σ( p + p μ + μ X ) E866 collaboration: PRL 100 (008) 06301 Drell J / Ψϒ, : Yan: σ σ pd pd pp 1 / σ [1 + d( x)/ u( x)] pp 1 / σ [1 + gn( x)/ gp( x)] 7
Is quark-antiquark annihilation the dominant mechanism at 30 GeV? u d d = u σ ( p+ d J / Ψ ) / σ ( p+ p J / Ψ) test for the production mechanism is a sensitive J/Ψ production at J-PARC could be sensitive to quark/antiquark distributions! 8
Expected J/Ψ yields and kinematic coverage J/Ψ yields for a two-month p+d run at 30 GeV Broad coverage in x F, x 1, x, p T Expected total number of J/Ψ events: ~ 8x10 6 10 1 protons/spill 50-cm long liquid deuterium target Assume 50 percent efficiency 9
Nuclear Dependence of J/Ψ Production at 30 GeV σ( p+ A) = A α σ( p+ N) 30 GeV data would provide an interesting test for the x F -scaling in J/ψ production Very few data exist for negative x F region 10
Polarization of J/ Ψ and Ψ Decay angular distribution in the quarkonium rest frame dσ 1+ λcos θ dω Transverse : σt ; helicity: ± 1; λ = 1 Longitudinal : σl ; helicity: 0; λ = -1 Unpolarized : σt=σl ; helicity: 0, ± 1; λ = 0 σt σl λ = = (1 σl / σt) / (1+ σl / σt) σ + σ σl / σt depends on the color - spin states of the QQ pair : 3 (1) 1 (8) 3 (8) 3 (8) State: S1 S0 PJ S1 σ / σ : 1/3.4 1/ 1/6 0/1 L T T L Polarization of QQ is sensitive to the production mechanism 11
Polarization of J/Ψ E866 p + Cu J/Ψ + x (beam dump) s 1/ = 38.8 GeV (PRL 91 (003) 1180,hep-ex/030801, T. Chang et al.) Typical dimuon mass spectrum for various xf, pt, cosθ bins dσ/dω ~ 1 + λcos θ (extraction of λ for various x F, p T bins) 1
Polarization of J/Ψ in p + Cu Collision dσ/dω ~ 1 + λ cos θ (λ=1: transversely polarized, λ = -1: longitudinally polarized λ = 0, unpolarized) E866 data hep-ex/030801 λ is small, but nonzero λ becomes negative at large x F No strong p T dependence for λ Polarization of Ψ has never been measured 13
Polarization of Υ(1S),Υ(S+3S) p + Cu Υ + x (E866 beam-dump data) Dimuon mass spectrum Decay angular distributions Υ(1S) Υ(S+3S) Brown et al. PRL 86, 59 (001) 14
Polarization of Υ(1S),Υ(S+3S) p + Cu Υ + x (E866 beam-dump data) λ λ λ for D-Y, Υ(1S), Υ(S+3S) p T (GeV) x F Brown et al. PRL 86, 59 (001) D-Y is transversely polarized Υ(1S) is slightly polarized (like J/Ψ) Υ(S+3S) is transversely polarized! Analysis of Y polarization in p+p and p+d is underway (nuclear dependence?) Preliminary result shows ψ is also transversely polarized! 15
Polarized proton beam at J-PARC? Polarized proton beam at J-PARC with Polarized H source RF dipole at 3 GeV RCS Two 30% partial snakes at 50 GeV Main Ring 30 GeV 50 GeV pc CNI Polarimeter Pol. H - Source Extracted Beam Polarimeter Rf Dipole 180/400 MeV Polarimeter 5-30% Helical Partial Siberian Snakes 16
Single-spin asymmetry in polarized p-p collision Large single-spin asymmetry in light meson production in polarized p-p: Sivers, Collins, and/or higher-twist effect? FNAL-E704 E lab = 00 GeV RHIC-STAR s = 00 GeV What is the single-spin asymmetry for J/Ψ production? 17
Single-spin asymmetry in polarized p-p at J-PARC Single-spin asymmetry (A N ) can probe Sivers function Sivers function in Drell-Yan is expected to have a sign opposite to that in DIS A DY N = q q e f ( x ) f ( x ) q 1T q q q e f ( x ) f ( x ) q q q q q -J/Ψ production could also probe the Sivers function - Much higher statistics could be obtained in J/Ψ production 18
Double-spin asymmetry in polarized p-p at J-PARC Double-spin asymmetry (A LL ) with longitudinally polarized beam/target in Drell-Yan (and J/Ψ) probe Sea-Quark polarization D-Y A LL at 50 GeV G-S A DY LL GRSV = a e [ Δq ( x ) Δ q ( x ) +Δq ( x ) Δq ( x )] a a 1 a a 1 a a e [ q ( x ) q ( x ) + q ( x ) q ( x )] a a 1 a a 1 a -J/Ψ production could also probe the Sea-Quark polarization - Much higher statistics could be obtained in J/Ψ production 19
Double-spin asymmetry in polarized p-p at J-PARC Double-spin asymmetry (A TT ) with transversely polarized beam/target in Drell-Yan (and J/Ψ) probe quark transversity distribution PHENIX, s 1/ =00GeV, 30 pb -1 5 A TT (M) [%] 4 3 1 0 NLO LO 4 6 8 10 1 14 16 18 0 M [GeV] A TT = aˆ TT q q eh( x, M ) h ( x, M ) q q q 1 1 1 eqx (, M ) q( x, M ) q 1 -J/Ψ production could also probe the transversity distribution - Much higher statistics could be obtained in J/Ψ production 0
Summary A rich physics program in J/Ψ production can be carried out at the J-PARC using primary proton beam. J/Ψ production at J-PARC energies is expected to be dominated by quark-antiquark annihilation, similar to Drell-Yan but with much larger cross sections. An extensive and exciting program in spin physics can be pursued if polarized proton and polarized targets are available at J-PARC. 1
Following slides are provided by Feng Yuan
Another example: Heavy flavor production Heavy quarkonium production (gg channel) ep scattering No SSA in color-singlet model Final state interaction in color-octet model pp scattering Only initial state interaction in color-singlet ISI and FSI cancel out in color-octet Open charm or beauty Different SSAs for charm and anti-charm 4/10/008 3 3
Color-singlet model Final state interactions with quark and anti-quark cancel out each other, no SSA in color-singlet model 4/10/008 4 4
Color-octet model Final state interactions can be summarized into a gauge link to infinity, nonzero SSA 4/10/008 5 5
pp scattering Color-singlet model: only initial state interaction, non-zero SSA Color-octet model: initial and final state interactions cancel out, no SSA 4/10/008 6 6
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J/Psi Production at lower energy (JPARC or FAIR) Quark-channel dominates Color-singlet: only initial state interaction contributes, -1/Nc relative to Drell-Yan Color-octet: both initial and final state interactions contribute, -(Nc^+1)/Nc relative to DY 4/10/008 DPN Meeting 007 8 8
JPARC prediction Final A_N depends on the weight of the quark-channel contribution Proportional to the sum of u- and d- quark Sivers function: fitted to HERMES data, Vogelsang-Yuan 05 4/10/008 DPN Meeting 007 9 9
Heavy quark SSA ISI: contribute to quark and anti-quark ~1/4Nc FSI: contribute to quark ~(Nc^-)/4Nc FSI: contribute to anti-quark ~/4Nc 4/10/008 DPN Meeting 007 30 30
FAIR at GSI 4/10/008 DPN Meeting 007 31 31
Summary We are in the early stages of a very exciting era of transverse spin physics studies, where the future RHIC, JLAB, JPARC, FAIR, and EIC experiments will certainly play very important roles We will learn more about QCD dynamics and nucleon structure from these studies, especially for the quark orbital motion 3 3