Rapidity Dependence of HBT radii based on a hydrodynamical model

We calculate two-pion correlation functions at finite rapidities based on a hydrodynamical model which does not assume explicit boost invariance along the collision axis. Extracting the HBT radii through $\chi^2$ fits in both Cartesian and Yano-Koonin-Podgoretski\u{\i} parametrizations, we compare them with the experimental results obtained by the PHOBOS. Based on the results, we discuss longitudinal expansion dynamics.Comment: 8 pages, 10 figures, talk given at II Workshop on Particle Correlation and Femtoscopy (WPCF 2006), Sep 9-11, Sao Paulo, Brazil. Revised version to be published in Braz.J.Phy

Quarkonium at T>0

We report recent progress on theoretical investigations of quarkonia at finite temperature. We discuss medium modification of charmonia and bottomonia from a viewpoint of local operators and point out that while charmonia are sensitive to the deconfinement transition bottomonia will be modified at much higher temperatures.Comment: Talk given at XLI International Symposium of Multiparticle Dynamics (ISMD 2011), 26-30, September 2011, Miyajima-Island, Hiroshima, Japan. 6 pages, 4 figures. To be published in Prog. Theor. Phys. Supp

Momentum scale dependence of the net quark number fluctuations near chiral crossover

We investigate properties of the net baryon number fluctuations near chiral crossover in a hot and dense medium of strongly interacting quarks. The chirally invariant quark-antiquark interactions are modeled by an effective quark-meson Lagrangian. To preserve remnants of criticality in the O(4) universality class, we apply the functional renormalization group method to describe thermodynamics near chiral crossover. Our studies are focused on the influence of the momentum cuts on the critical behavior of different cumulants of the net quark number fluctuations. We use the momentum scale dependence of the flow equation to examine how the suppression of the momentum modes in the infrared and ultraviolet regime modifies generic properties of fluctuations expected in the O(4) universality class. We show, that the pion mass $m_\pi$ is a natural soft momentum scale at which cumulants are saturated at their critical values, whereas for scales larger than $2m_\pi$ the characteristic O(4) structure of the higher order cumulants get lost. These results indicate, that when measuring fluctuations of the net baryon number in heavy ion collisions to search for a partial restoration of chiral symmetry or critical point, a special care have to be made when introducing kinematical cuts on the fluctuation measurements.Comment: 15 pages, 8 figures. To appear in Prog. Theor. Exp. Phy

pΞ−p\Xi^- Correlation in Relativistic Heavy Ion Collisions with Nucleon-Hyperon Interaction from Lattice QCD

On the basis of the $p\Xi^-$ interaction extracted from (2+1)-flavor lattice QCD simulations at the physical point, the momentum correlation of $p$ and $\Xi^-$ produced in relativistic heavy ion collisions is evaluated. $C_{\rm SL}(Q)$ defined by a ratio of the momentum correlations between the systems with different source sizes is shown to be largely enhanced at low momentum due to the strong attraction between $p$ and $\Xi^-$ in the $I=J=0$ channel. Thus, measuring this ratio at RHIC and LHC and its comparison to the theoretical analysis will give a useful constraint on the $p\Xi^-$ interaction.Comment: 4 pages, 2 figures; proceedings contribution for Quark Matter 201

HBT Effect Based on a Hydrodynamical Model

We investigate HBT radii based on the numerical solutions of the hydrodynamical model which are so tuned as to reproduce the recent experimental data at the CERN SPS. Comparing the sizes of freeze-out hypersurface with HBT radii, we discuss dynamical effect of the systematic flow on the apparent HBT radii. Finally we compare HBT radii of the QGP phase transition model with those of the hadron gas model without phase transition.Comment: 5 pages, LaTeX, 7 EPS figures. Talk at the International School on the Physics of Quark Gluon Plasma, June 3-6, 1997, Hiroshima, Japa