470 likes | 676 Views
Perturbative QCD apporach to Heavy quarkonium at finite temperature and density. Su Houng Lee Yonsei Univ., Korea. Introduction on sQGP and Bag model Gluon condensates in sQGP and in vacuum J/ y suppression in RHIC Pertubative QCD approach for heavy quarkonium.
E N D
Perturbative QCD apporach to Heavy quarkonium at finite temperature and density Su Houng Lee Yonsei Univ., Korea • Introduction on sQGP and Bag model • Gluon condensates in sQGP and in vacuum • J/y suppression in RHIC • Pertubative QCD approach for heavy quarkonium Thanks to : Recent Collegues: C.M. Ko, W. Weise, B. Friman, T. Barnes, H. Kim, Y. Oh, .. Students: Y. Sarac, Taesoo Song, Y. Park, Y. Kwon, Y. Heo,..
Quark Gluon Plasma (T.D. Lee and E. Shuryak) Proton Proton At high T and/or Density Proton Nucleons in vacuum Quark Gluon Plasma
QCD Phase Diagram at finite T and r Quark Gluon Plasma (sQGP) ~ 170 MeV 0.17 / fm3 Lattice result: sudden change in p and E above Tc • Different • Particle spectrum (mass) • Vacuum • Deconfinement • Theoretical approach
Relativistic Heavy Ion collision Signal of QGP
Some highlights from RHIC Data from STAR coll. At RHIC Jet quenching: strongly interacting matter V2: very low viscosity
sQGP strongly interacting and very small viscosity Vacuum property of sQGP MIT Bag model and Quark Gluon Plasma (QGP)
Bag model and sQGP Outside pressure is balanced by confined quark pressure MIT Bag model : inside the Bag fvac=0, perturbative vacuume outside the Bag fvac = non zero , non perturbative vacuum Original bag model Later models
Bag model and sQGP Outside pressure is balanced by thermal quark gluon pressure Asakawa, Hatsuda PRD 97 Phase transition in MIT Bag model
QCD vacuum vs. sQGP Vacuum with negative pressure Nonperturbative QCD vacuum sQGP MIT Bag • What is B in terms of QCD variables (operators) • Can understand soft modes associated with phase transition
Gluon condensate • , dominated by non-perturbative contribution 4. Related to trace of energy momentum tensor through trace anomaly (Hatsuda 87) 5. Nucleon expectation value is 6. From we find 2. RG invariant, gauge invariant, characteristic vacuum property, couples to spin 0 field 3. Can be calculated on the lattice (DiGiacomo et al. )
Gluon condensate in MIT Bag model Using Inside nucleon Inside QGP Explicit lattice calculation of non-perturbative gluon condensate?
Lattice data show 1. Gluon condensate at T=0 is consistent with QCD sum rule value 2. Gluon condensate at T>Tc is 50 to 70 % of its vacuum value consistent with estimates of gluon condensate inside the Bag (nucleon) 3. The change occurs at the phase transition point T D Lee’s spin 0 field seems dominantly gluon condensate and their expectation value indeed changes similarly in Bag and QGP
QCD vacuum vs. sQGP Vacuum with negative pressure Nonperturbative QCD vacuum sQGP MIT Bag If phase transition occurs, there will be enhancement of massless glueball excitation
Summary I 1. Vacuum expectation value of Gluon condensate inside the Bag and QGP seems similar. sQGP is a large Bag What will the viscosity be ?? What is the property of sQGP? Physical consequence of phase transition? 2. Future GSI (FAIR) will be able to prove vacuum change through charmonium spectrum in nuclear matter
J/y in Quark Gluon Plasma J/y melt above Tc Heavy quark potential on the lattice Karsch et al. (2000)
J/y suppression in Heavy Ion collision New RHIC data 1986: Matsui and Satz claimed J/y suppression is a signature of formation of Quark Gluon Plasma in Heavy Ion collision
J/y in Quark Gluon Plasma Quenched lattice calculation by Asakawa and Hatsuda using MEM T< 1.6 Tc T> 1.6 Tc J/y peak at 3.1 GeV 2003: Asakawa and Hatsuda claimed J/y will survive up to 1.6 Tc
Theoretical interpretations 1. C. H. Lee, G. Brown, M. Rho… : Deeply bound states 2. C. Y. Wong… : Deby screened potential • 1. Strong as at Tc < T < ~2 Tc • 2. J/y form Coulomb bound states at Tc < T < ~2 Tc
Relevant questions in J/y suppression need to know J/y – gluon dissociation need to know J/y – quark dissociation Became a question of quntative analysis a) What are the effects of Dynamical quarks ? b) What is the survial probability of J/y in QGP
Progressin QCD calculations LO and NLO
Basics in Heavy Quark system 1. Heavy quark propagation Perturbative treatment are possible because
2. System with two heavy quarks Perturbative treatment are possible when
Historical perspective on Quarkonium Haron interaction in QCD • Peskin (79), Bhanot and Peskin (79) • a) From OPE • b) Binding energy= e0 >> L • Kharzeev and Satz (94,96) , Arleo et.al.(02,04) • a) Rederive, target mass correction • b) Application to J/y physics in HIC
Rederivation of Peskin formula using Bethe-Salpeter equation (Lee,Oh 02) Resum Bound state by Bethe-Salpeter Equation
NR Power counting in Heavy bound state 1. Perturbative part 2. External interaction: OPE
2 1 3 Exp data However, near threshold, LO result is expected to have large correction mb s1/2 (GeV)
q1 NLO Amplitude : Collinear divergence when q1=0. Cured by mass factroization
q1 q1 Integration of transverse momentum from zero to scale Q Mass factorization Gluons whose kcos q1 < Q scale, should be included in parton distribution function
NLO Amplitude : Higher order in g counting
NLO Amplitude : - cont Previous diagrams can be reproduced with effective four point vertex
Cancellation of infrared divergence Remaining Infrared Divergence cancells after adding one loop corrections
Application to Upsilon dissociation cross section Fit quark mass and coupling from fitting to coulomb bound state gives
Total cross section for Upsilon by nucleon: NLO vs LO NLO/LO Large higher order corrections Even larger correction for charmonium
Thermal quark and gluon masses of 300 MeV will Reduce the large correction What do we learn from NLO calculation ? 1. Large NLO correction near threshold, due to log terms 2. Dissociation by quarks are less than 10% of that by gluons << Quenched lattice results at finite temperature are reliable
Total cross section: gluon vs quark effects With thermal mq = mg = 200 MeV
Summary II • We reported on the QCD NLO Quarkonium-hadron dissociation cross section. Large correction even for upsilon system, especially near threshold 2. The corrections becomes smaller with thermal quark and gluon mass of larger than 200 MeV Obtained realisticJ/y dissociation cross section by thermal quark and gluons 3. The dissociation cross section due to quarks are less than 10 % of that due to the gluons. The quenched lattice calculation of the mass and width of J/y at finite temperature should be reliable.
Reference for part I Gluon condensates • A. Di Giacomo and G. C. Rossi, PLB 100(1981) 481; PLB 1008 (1982) 327. • Su Houng Lee, PRD 40 (1989) 2484. Charmonium in nuclear matter • F. Klingl, S. Kim, S.H.Lee, P. Morath, W. Weise, PRL 82 (1999) 3396. • S.Kim and S.H.Lee, NPA 679 (2001) 517. • S.H.Lee and C.M. Ko, PRC 67 (2003) 038202. • S.J.Brodsky et al. PRL 64 (1990) 1011 Quarkonium hadron interaction 7. M.E. Peskin, NPB 156 (1979) 365; G.Bhanot and M. E. Peskin, NPB156 (1979) 391 • Y.Oh, S.Kim and S.H.Lee, PRC 65 (2002) 067901. Additional 9. T.D. Lee, hep-ph/06 05017