Wounded-nucleon model with realistic nucleon-nucleon collision profile and observables in relativistic heavy-ion collisions

Abstract

We investigate the influence of the nucleon-nucleon collision profile (probability of interaction as a function of the nucleon-nucleon impact parameter) in the wounded nucleon model and its extensions on several observables measured in relativistic heavy-ion collisions. We find that the participant eccentricity coefficient, ǫ * , as well as the higher harmonic coefficients, ǫ * n , are reduced by 10-20% for mid-peripheral collisions when the realistic (Gaussian) profile is used, as compared to the case with the commonly-used hard-sphere profile. Similarly, the multiplicity fluctuations, treated as the function of the number of wounded nucleons in one of the colliding nuclei, are reduced by 10-20%. This demonstrates that the Glauber Monte Carlo codes should necessarily use the realistic nucleon-nucleon collision profile in precision studies of these observables. Our study is relevant for hydrodynamic calculations which use the Glauber-model initial conditions. The Gaussian collision profile is built-in in GLISSANDO.

Collective flow in ultrarelativistic 3 He–Au collisions

“…This has a significant effect on the fireball shape and size in small systems, as noticed in Ref. [7,30]. In Fig.…”

Influence of initial fluctuations on geometry measures in relativistic U+U and Cu+Au collisions

“…[57], the NN wounding profile in the form of a combination of Gaussians can precisely reproduce the CERN Intersecting Storage Rings (ISR) experimental data [60][61][62][63][64] on the total and elastic differential p + p cross section. Here we use a single-Gaussian form, which for the studied heavy-ion observables is accurate enough [9]:…”

“…The Glauber model approach provides initial conditions for the subsequent hydrodynamic evolution. That way the features of the nuclei structure, such as distributions of nucleons in nuclei, the nucleon-nucleon (NN) correlations [8], as well as the NN cross section [9] show up indirectly in the measured observables. Moreover, as argued by Filip et al [10][11][12], the nucleus deformation plays an important role in the "geometry" of the collision.…”

“…This profile is related to the differential NN cross section [57]. We have shown previously that the single-Gaussian wounding profile is sufficiently accurate and is the physical choice [9], differing in predictions for the fluctuation measures from the commonly used but inappropriate hard-sphere wounding profile. …”

Initial state fluctuations and final state correlations in relativistic heavy-ion collisions

“…1) [85]. Different implementations of the finite size effect have an influence on eccentricity already for smooth initial conditions [86].…”