Study of $p_\mathrm{T}$-differential radial flow in blast-wave model

Fuente: arXiv
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Main Authors: Saha, Swati, Singh, Ranbir, Mohanty, Bedangadas
Format: Preprint
Published: 2025
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_version_ 1866913859499982848
author Saha, Swati
Singh, Ranbir
Mohanty, Bedangadas
author_facet Saha, Swati
Singh, Ranbir
Mohanty, Bedangadas
contents The transverse momentum-differential radial flow observable $v_0(p_\mathrm{T})$, recently proposed and measured by the ATLAS and ALICE collaborations, provides a novel tool to probe radial expansion dynamics in high-energy heavy-ion collisions. In this work, we conduct a detailed study of $v_0(p_\mathrm{T})$ using a blast-wave model that incorporates hydrodynamic-like expansion and thermal emission. We introduce event-by-event fluctuations in the transverse expansion velocity and kinetic freeze-out temperature using Gaussian probability distributions. Our results show that increasing the mean expansion velocity leads to a clear mass ordering in $v_0(p_\mathrm{T})$, while fluctuations in both expansion velocity and freeze-out temperature significantly enhance the magnitude of $v_0(p_\mathrm{T})$, particularly at higher $p_\mathrm{T}$. We fit blast-wave model calculations for identified hadrons ($π$, K, and p) to recent ALICE data from Pb--Pb collisions at $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV using a Bayesian parameter estimation framework. The extracted mean transverse expansion velocity decreases, while the kinetic freeze-out temperature increases, from central to peripheral collisions. Additionally, the freeze-out temperatures inferred from $v_0(p_\mathrm{T})$ are systematically higher than those obtained from conventional $p_\mathrm{T}$-spectra fits, likely due to the reduced sensitivity of $v_0(p_\mathrm{T})$ to resonance decay contributions.
format Preprint
id arxiv_https___arxiv_org_abs_2505_19697
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Study of $p_\mathrm{T}$-differential radial flow in blast-wave model
Saha, Swati
Singh, Ranbir
Mohanty, Bedangadas
Nuclear Experiment
High Energy Physics - Experiment
High Energy Physics - Phenomenology
Nuclear Theory
The transverse momentum-differential radial flow observable $v_0(p_\mathrm{T})$, recently proposed and measured by the ATLAS and ALICE collaborations, provides a novel tool to probe radial expansion dynamics in high-energy heavy-ion collisions. In this work, we conduct a detailed study of $v_0(p_\mathrm{T})$ using a blast-wave model that incorporates hydrodynamic-like expansion and thermal emission. We introduce event-by-event fluctuations in the transverse expansion velocity and kinetic freeze-out temperature using Gaussian probability distributions. Our results show that increasing the mean expansion velocity leads to a clear mass ordering in $v_0(p_\mathrm{T})$, while fluctuations in both expansion velocity and freeze-out temperature significantly enhance the magnitude of $v_0(p_\mathrm{T})$, particularly at higher $p_\mathrm{T}$. We fit blast-wave model calculations for identified hadrons ($π$, K, and p) to recent ALICE data from Pb--Pb collisions at $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV using a Bayesian parameter estimation framework. The extracted mean transverse expansion velocity decreases, while the kinetic freeze-out temperature increases, from central to peripheral collisions. Additionally, the freeze-out temperatures inferred from $v_0(p_\mathrm{T})$ are systematically higher than those obtained from conventional $p_\mathrm{T}$-spectra fits, likely due to the reduced sensitivity of $v_0(p_\mathrm{T})$ to resonance decay contributions.
title Study of $p_\mathrm{T}$-differential radial flow in blast-wave model
topic Nuclear Experiment
High Energy Physics - Experiment
High Energy Physics - Phenomenology
Nuclear Theory
url https://arxiv.org/abs/2505.19697