Signals of the QCD Critical Point in Hydrodynamic Evolutions

The presence of a critical point in the QCD phase diagram can deform the trajectories describing the evolution of the expanding fireball in the QCD phase diagram. The deformation of the hydrodynamic trajectories will change the transverse velocity dependence of the proton-antiproton ratio when the fireball passes in the vicinity of the critical point. An unusual transverse velocity dependence of the anti-proton/proton ratio in a narrow beam energy window would thus signal the presence of the critical point.Comment: 4 pages, 6 figures, 21st International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (QM2009) 30 Mar - 4 Apr 2009, Knoxville, Tennesse

Elliptic flow of resonances at RHIC: probing final state interactions and the structure of resonances

We propose the measurement of the elliptic flow of hadron resonances at the Relativistic Heavy Ion Collider as a tool to probe the amount of hadronic final state interactions for resonances at intermediate and large transverse momenta. This can be achieved by looking at systematic deviations of the measured flow coefficient $v_2$ from the scaling law given by the quark recombination formalism. Our method can be generalized to explore the structure of exotic particles, such as the recently found pentaquark $\Theta^+ (1540)$.Comment: 5 pages, 2 figures; v2: accepted version for publication in Physical Review C rapid communication

Possible Resolutions of the D-Paradox

We propose possible ways of explaining the net charge event-by-event fluctuations in Au+Au collisions at the Relativistic Heavy Ion Collider within a quark recombination model. We discuss various methods of estimating the number of quarks at recombination and their implications for the predicted net charge fluctuations. We also discuss the possibility of diquark and quark-antiquark clustering above the deconfinement temperature.Comment: 5 pages, 2 figure

Transverse Velocity Dependence of the Proton-Antiproton Ratio as a Signature of the QCD Critical Endpoint

The presence of a critical point in the QCD phase diagram can deform the trajectories describing the evolution of the expanding fireball in the $\mu_B-T$ phase diagram. If the average emission time of hadrons is a function of transverse velocity, as microscopic simulations of the hadronic freeze-out dynamics suggest, the deformation of the hydrodynamic trajectories will change the transverse velocity ($\beta_{\rm T}$) dependence of the proton-antiproton ratio when the fireball passes in the vicinity of the critical point. An unusual $\beta_{\rm T}$-dependence of the $\bar{p}/p$ ratio in a narrow beam energy window would thus signal the presence of the critical point.Comment: Final version accepted for publicatio