Study of octupole deformations in Pb-Pb collisions at 5.02 TeV

TL;DR

This study investigates how octupole deformation in nuclei influences key observables in Pb-Pb collisions at 5.02 TeV, revealing correlations between nuclear shape parameters and flow measurements in heavy-ion collisions.

Contribution

It introduces a detailed analysis of octupole deformation effects on QGP observables using the HYDJET++ model in different collision geometries.

Findings

Charged hadron multiplicity depends on octupole deformation strength.

Flow coefficients show weak correlation with octupole deformation parameter.

Differences observed between body-body and tip-tip collision configurations.

Abstract

In this letter, we present the study of the role of octupole deformation in non-spherical nuclei in most-central Pb--Pb collisions at the LHC energy regime. The sensitivity of octupole deformation $\beta_3$ to the QGP observables is presented by employing the Monte Carlo HYDJET++ model. Motivated by the discrepancies in the $v_2$-to-$v_3$ puzzle found in Pb--Pb collisions and the low-energy nuclear structure calculations of nuclear deformation, we studied the first basic observables necessary for any study in heavy-ion collisions. Using the HYDJET++ framework, we calculate the pseudorapidity distribution, transverse momentum ($p_{\mathrm{T}}$) spectra, and average anisotropic flow ($v_2$ and $v_3$) of primary charged hadrons with different parameters in two geometrical configurations: body-body and tip-tip types of Pb--Pb collisions. The kinematic ranges $0 < p_{\mathrm{T}} < 20~\mathrm{GeV}/c$ and $|\eta| < 0.8$ are considered. We observe that the charged hadron multiplicity and transverse momentum spectra are dependent on the strength of the octupole deformation parameter. The $\langle v_2 \rangle$ and $\langle v_3 \rangle$ in body-body collisions show a weak positive correlation with $\beta_3$, while the average anisotropic flow in tip-tip collisions is weakly correlated with $\beta_3$ in the most-central collision region.