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TOPICS DISCUSSED Contd. 6. Bound states above critical temperature 7. Higher order susceptibilities 8. Ads/CFT – QCD/QGP ? 9. Neutrino emission from crystalline color superconducting quark matter
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WG4 (QGP) REPORT Sudhir Raniwala, MG. Mustafa, S.K. Ghosh, R.S.
Bahalerao, L. Ramello, Jajati Nayak, Rajarshi Ray, S.C. Phatak, V.K. Tiwari, R.V. Gavai, A.M. Srivastava, G.C. Mishra, A.P. Mishra, A.K. Rath, P.K. Sahu
Some formal talks and some ‘informal’ talks led to discussions and identifying
problems
TOPICS DISCUSSED1. Charmonium Suppression2. Jets3. Thermal and Direct Photons4. Hydrodynamic description of elliptic flow
Experimental data, unanswered questions Theory, Predictions Implementation and comparing techniques
5. Phi production at RHIC
TOPICS DISCUSSED Contd.
6. Bound states above critical temperature
7. Higher order susceptibilities8. Ads/CFT – QCD/QGP ?9. Neutrino emission from crystalline
color superconducting quark matter
1. Charmonium Suppression Talk by Luciano Ramello (INFN, Italy)
Results from NA50 and NA60 experiment. • Improved technique for background• J/Ψ absorption σ ~ 4.3 mb (p-A data only)
• earlier using S+U also, obtained ~7mb• Significant suppression in Pb+Pb and In+In• Suppression observed in RHIC• New models also including charm
recombination• No single model able to describe details of
the data on In+In and Pb+Pb• Recombination needed at RHIC
2. Jets Identify jets using Fourier expansion (S.C.Phatak) Method based on analysis of pT weighted flow coeff.
To be tested with jets in events in relativistic heavy ion collision environment
Cone algorithm, kT algorithm (Kosower, Contreras) Some features that test goodness of the algorithms
• Infrared safe, Collinear safe, Independent of renormalization and factorization scale
• Amenable to comparison between theory and experiment
Suggested a problem for the LHC nvironment:• Study the dependence on the number, energy,
rapidity of the jets and the influence of the underlying event which may include mini jets
3. Thermal and Direct Photons Discussion led by Terry Awes
NLO pQCD predictions describe direct photon p+p data well, at low √s where kT broadening has been introduced to explain.
Direct photons observed in Pb+Pb collisions at SPS energies (√s =17.GeV) can be described by • thermal emission (QGP+HG) with high initial
temperature (~300MeV). • additional kT broadening.
Direct photons at RHIC agree with NLO pQCD in p+p and at high pT in central Au+Au. Results for central Au+Au are consistent with thermal emission with initial T up to ~600MeV.
Other new techniques to extract low pT direct photon signal such as - HBT, - flow, and low mass electron pairs are being pursued.
4. Hydrodynamic Description of Elliptic Flow
Discussion led by R. Bhalerao Ideal hydrodynamics does not quantitatively reproduce
pT-dependent flow of identified particles in centrality-selected bins
Estimated Mach, Knudsen and Reynolds numbers for RHIC and argued inadequacy of ideal hydrodynamics
Emphasised the need for Relativistic Dissipative Hydrodynamics…described the broad framework
“Three pT regions” of elliptic flow at RHIC Comparison of different techniques for different
experimental conditions (Standard Method, Lee-Yang zeroes)
5. Phi production at RHIC Talk by Jajati Nayak
Production and evolution of strange particles Extract effective degrees of freedom that
characterize the coexisting phase and set a lower limit on Tc and geff
Overproduction takes place in mixed phase if Tc beyond 160 MeV
6. Bound states above Tc
R. Ray, S. K. Ghosh & M. G. Mustafa
New lattice results indicate bound states above Tc
Spectral analysis for bound states J/, ’ etc. Heavier bound states survive up to larger T (~2Tc)
Lattice equation of state deviates from SB• Quarks and gluons not free
Pressure puzzle: resolved by putting colored b.s. (quasiparticles, coloured & colourless b.s.)
These have large σ…..leading to collective flow and low viscosity…..the sQGP Existence of binding potential
Tasks: Improvise on potential and equation of motion, improve determination of m, MD, s
7. Higher Order Susceptibilities Discussion led by R.Gavai
Lattice results on quark number susceptibilities provide new insights
2 behaves like an order parameter
4 and 6 also behave drastically around Tc
pQCD and existing models failed to explain these results
need for improved models !!!
Model which can explain EOS as well as all
8. Ads/CFT – QCD/QGP ? Discussion led by Balram
RHIC results indicate formation of “perfect liquid”
• η/S ~ 0.1 – 0.2, strongly coupled system, motivating description as hydrodynamic behaviour with low η
Need reliable estimates of transport coefficients in FT-QCD in strong coupling limit
AdS/CFT correspondence with N = 4 supersymmetric YM theory with FT in strong coupling limit may put a lower bound η/S ~ 0.1 (Liquid He ~9, Water ~380)
AdS/CFT QCD/QGP ? (coincidence or reality?)
9. Neutrino emission from crystalline color superconducting quark matter
P.Jaikumar and H. Mishra Identifying the proper ground state
Determine the excitation spectrum (considering simple case)
Use dispersion relation to compute neutrino emissivity and specific heat capacity
Determine the cooling rate and compare with data on observed Neutron Star temperature