F. Grassi
From an analysis of various types of data obtained in relativistic nuclear collisions, the following picture has emerged in thermal and hydrodynamical descriptions: as the fluid expands and cools, particles first undergo a chemical freeze…
A survey of various mechanisms for particle emission in hydrodynamics is presented. First, in the case of sudden freeze out, the problem of negative contributions in the Cooper-Frye formula and ways out are presented. Then the separate…
Freeze-out of particles across 3-dimensional space-time hypersurface with space-like normal is discussed in a simple kinetic model. The final momentum distribution of emitted particles shows a non-exponential transverse momentum spectrum,…
We study the behaviour of the effective temperature for K$^+$ in several energy domains. For this purpose, we apply the recently developed SPheRIO code for hydrodynamics in 3+1 dimensions, using both Landau-type compact initial conditions…
A unified description of the near-side and away-side structures observed in two-particle correlations as function of delta eta-delta phi is proposed for low to moderate transverse momentum. It is based on the combined effect of tubular…
In a recent paper, the hydrodynamic code NEXSPheRIO was used in conjunction with STAR analysis methods to study two-particle correlations as function of Delta-eta and Delta-phi. The various structures observed in data were reproduced. In…
The effects of fluctuating initial conditions are studied in the context of relativistic heavy ion collisions where a rapidly evolving system is formed. Two particle correlation analysis is applied to events generated with the NEXSPHERIO…
The interplay between shear and bulk viscosities on the flow harmonics, $v_n$'s, at RHIC is investigated using the newly developed relativistic 2+1 hydrodynamical code v-USPhydro that includes bulk and shear viscosity effects both in the…
Event-by-event hydrodynamics (or hydrodynamics with fluctuating initial conditions) has been developed in the past few years. Here we discuss how it may help to understand the various structures observed in two-particle correlations.
Elliptic flow at RHIC is computed event-by-event with NeXSPheRIO. Reasonable agreement with experimental results on $v_2(\eta)$ is obtained. Various effects are studied as well: reconstruction of impact parameter direction, freeze out…
Effects of lattice-QCD-inspired equations of state and continuous emission on some observables are discussed, by solving a 3D hydrodynamics. The particle multiplicity as well as v2 are found to increase in the mid-rapidity. We also discuss…
Freeze out of particles across three dimensional space-time hypersurface is discussed in a simple kinetic model. The final momentum distribution of emitted particles, for freeze out surfaces with space-like normal, shows a non-exponential…
We study the effects of strict conservation laws and the problem of negative contributions to final momentum distribution during the freeze out through 3-dimensional hypersurfaces with space-like normal. We study some suggested solutions…
In order to actually see the hadron-quark transition happening in a neutron star, we point out and study two static conditions (the transition hadronic density must be lower than the neutron star maximum hadronic density; the neutron star…
We show that a hadron gas model with continuous particle emission instead of freeze out may solve some of the problems (high values of the freeze out density and specific net charge) that one encounters in the latter case when studying…
We show effects of granular structure of the initial conditions (IC) of hydrodynamic description of high-energy nucleus-nucleus collisions on some observables, especially on the elliptic-flow parameter v2. Such a structure enhances…
We show effects of the event-by-event fluctuation of the initial conditions (IC) in hydrodynamic description of high-energy nuclear collisions on some observables. Such IC produce not only fluctuations in observables but, due to their bumpy…
A comparison is made between results obtained using smooth initial conditions and event-by-event initial conditions in the hydrodynamical description of relativistic nuclear collisions. Some new results on directed flow are also included.
Freeze out of particles across a space-time hypersurface is discussed in kinetic models. The calculation of final momentum distribution of emitted particles is described for freeze out surfaces, with spacelike normals. The resulting…
Elliptic flow at RHIC is computed event-by-event with NeXSPheRIO. We show that when symmetry of the particle distribution in relation to the reaction plane is assumed, as usually done in the experimental extraction of elliptic flow, there…