Quarkonium as Signal of Deconfinement

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## Quarkonium as Signal of Deconfinement

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**Quarkonium as Signal of Deconfinement**Ágnes Mócsy Thanks to Sourendu, Saumen, Rajeev, Rajiv!**In this talk:**• Why quarkonium at finite T interesting • Initial interpretation of quarkonium lattice data • Results from potential model. Comparison to lattice • Upper limit binding energies. Estimates of upper limit dissociation T • Comments on the potential • Conclusions based onÁ. Mócsy, P. Petreczky Phys. Rev. D 77, 014501 (2008) Phys. Rev. Lett. 99, 211602 (2007)**Color Screening**J/ melting V(r) confined deconfined J/ r can signal QGP formation in heavy ion collisions Matsui and Satz (1986) Screening in deconfined matter weakens potential (force) between heavy quark and antiquark.**Color Screening**J/ melting RBC-Bielefeld Collab. (2007) Free energy of a static Q-Qbar in Nf=2+1 can signal QGP formation in heavy ion collisions Matsui and Satz (1986) Poster by K.Petrov Screening in deconfined matter weakens potential (force) between heavy quark and antiquark. Strong screening seen in Lattice Model independent statement Range of interaction between Q and Qbar is strongly reduced With increasing T screening sets in at shorter and shorter distances**Color Screening**J/ melting T/TC 1/r [fm-1] (1S) J/(1S) b’(2P) c(1P) ’’(3S) RBC-Bielefeld Collab. (2007) ’(2S) Free energy of a static Q-Qbar in Nf=2+1 can signal QGP formation in heavy ion collisions Matsui and Satz (1986) Strong screening seen in Lattice QGP thermometer Model independent statement Range of interaction between Q and Qbar is strongly reduced With increasing T screening sets in at shorter and shorter distances**Color Screening**J/ melting T/TC 1/r [fm-1] NA50 at SPS (0<y<1) PHENIX at RHIC (|y|<0.35) (1S) J/(1S) Bar: uncorrelated error Bracket : correlated error Global error = 12% is not shown b’(2P) c(1P) ’’(3S) ’(2S) can signal QGP formation in heavy ion collisions Matsui and Satz (1986) J/ suppression measured at SPS and RHIC QGP thermometer Must know quarkonia properties, dissociation temperatures!**Potential Models**Lattice QCD**c**Spectral Functions Extracted from Lattice Unified treatment of bound-, scattering states, threshold effects Asakawa, Hatsuda, Umeda, Datta et al, Iida, Jakovac et al, Aarts et al … Common interpretation: 1S ground state survives (unaffected) well above TC Started an avalanche of new potential model works to explain J/ survival Digal et al,Shuryak,Zahed,Blaschke,Wong, Rapp, Alberico,Manarelli, Cabrera, … Jakovác,Petreczky,Petrov,Velitsky PRD (2007) Would the J/survive unaffected in the QGP up to 1.5-2Tc even though strong screening is present ?**to answer, Look at**Euclidean-time Correlators Because: Mócsy, Petreczky PRD 2005 1. Numerical results more reliable - directly measured on the Lattice Correlator MEASURED Spectral Function EXTRACTEDwith MEM Kernel cosh[(-1/2T)]/sinh[/2T] 2. Ratio of correlators eliminates trivial T-dependence of K 3. In ratio lattice artifacts understood -Mócsy, Petreczky EJP 2007**= 1**spectral function unchanged, state survives • 1 spectral function modified, state melts c c Datta et al PRD 04 Datta et al PRD 04 compare to lattice data calculate in potential model Initial interpretation: J/(c)survives up to1.5-2Tcand cmelts by 1.1 Tchas been reported Potential models must be checked for agreement with lattice data on correlators as well**Correlator at T=0**Lattice data from Datta et al, PRD 05 Relativistic continuum Non-relativistic continuum Mócsy, Petreczky, PRD 08 Relativistic continuum seen on the lattice in contradiction with statements made in the literature**~ 2%**Lattice data Potential Model with Nf=0 Pseudoscalarresults with potential constrained by lattice free energy data c For the First TimeAgreement between potential model and lattice correlators to few % and for all states No resonance-like structures at 1.2Tc Seemingly contradicts previous claims. Details cannot be resolved Jakovác et al PRD (07) Lattice data is consistent with J/ melting above Tc Near threshold there is an enhancement above free quark propagation. Indicates correlation. Threshold enhancement compensates for melting of states**1.5 Tc**Zero mode is not present in the derivative of correlator followingUmdeda, PRD 07 Dissolution of the c does not lead to large increase in the correlator Zero-mode contribution Scalar channel contains low frequency contribution at finite temperature Bound and unbound Q-Qbar pairs (>2mQ) Quasi-free heavy quarks interacting with the medium Constant contribution in the correlator quark number susceptibility Threshold enhancement compensates for dissolution of states**Potential Model with Nf=2+1**Potential constrained by lattice free energy data w. realistic quark masses Spectral function may show resonance-like peak structures but binding energy can be small { Ebin = 2mq+V∞(T)-M distance between peak position and continuum threshold When Ebin < T, state is waekly bound and thermal fluctuations can destroy it.Do not need to reach the usual Ebin=0 to dissociate a state.**strong binding**weak binding Binding Energy Upper Limit 1. Use the most confining potential still consistent with full QCD lattice data on static Q-antiQ energies 2. Estimate dissociation rate due to thermal activation (width) Ebin< T followingKharzeev,McLerran,Satz, PLB 95 3. Ad hoc choice dissociation condition: Thermal width > 2 x Binding energy**T/TC**1/r[fm-1] (1S) 2 b(1P) 1.2 J/(1S) ’(2S) b’(2P) ’’(3S) TC c(1P) ’(2S) Dissociation Temperatures in QCD Upper Bound estimate Mócsy, Petreczky PRL (2007) Calibration of the QGP thermometer • Implications for heavy ion phenomenology to consider • Similarity of J/ RAA at SPS and RHIC? • Upsilon suppression at RHIC?**T=0 potential**lattice internal energy lattice free energy Comment on the potential Set of potentials at 1.2Tc G/Grec from set of potentials all agree with correlator lattice data pseudoscalar**Summary**For the first Time agreement is found between a potential model and lattice correlators for all states • Lattice data are consistent with J/ dissociation just above Tc • what has changed?Flatness of G/Grec and lattice spectral function peak does not necessarily imply survival, as it was thought before. • Increase in correlators is due to different physics, not dissociation. G/Grec are flat in all channels. Indication of Q-Qbar correlation. Determined upper limit on binding energies using lattice data on free and internal energy together with potential model. Estimate of upper limit on dissociation temperatures indicate that most states except the andbare dissolved close to Tc