Quantification of the low-$p_{\mathrm{T}}$ pion excess in heavy-ion collisions at the LHC and top RHIC energy

Abstract

While the abundances of the final state hadrons in relativistic heavy-ion collisions are rather well described by the thermal particle production, the shape of the transverse momentum, $p_{\mathrm{T}}$, distribution below $p_{\mathrm{T}}\approx 500$ MeV$/c$, is still poorly understood. We propose a procedure to quantify the model-to-data differences using Bayesian inference techniques, which allows for consistent treatment of the experimental uncertainties and tests the completeness of the available hydrodynamic frameworks. Using relativistic fluid framework Fluid$u$M with PCE coupled to \trento initial state and FastReso decays, we analyse \pt distribution of identified charged hadrons measured in heavy-ion collisions at top RHIC and the LHC energies, and identify an excess of pions produced below $p_{\mathrm{T}}\approx 500$ MeV$/c$. Our results provide new input for the interpretation of the pion excess as either missing components in the thermal particle yield description or as an evidence for a different particle production mechanism.

9 pages, 6 figures

References in corpus (14)

• Systematic Measurements of Identified Particle Spectra in pp, d+Au and Au+Au Collisions from STAR
• Alternative ansatz to wounded nucleon and binary collision scaling in high-energy nuclear collisions
• Bayesian analysis of heavy ion collisions with the heavy ion computational framework Trajectum
• Running the gamut of high energy nuclear collisions
• The ALICE experiment: a journey through QCD
• Evidence of the triaxial structure of ${}^{129}$Xe at the Large Hadron Collider
• Chemical freeze-out temperature in hydrodynamical description of Au+Au collisions at sqrt(s_NN) = 200 GeV
• Bose-Einstein condensation of pions in heavy-ion collisions at the CERN Large Hadron Collider (LHC) energies
• Identified hadron transverse momentum spectra in Au+Au collisions at sqrt(s_(NN))=62.4 GeV
• Production of pions, kaons, (anti-)protons and $\varphi$ mesons in Xe-Xe collisions at $\sqrt{s_{\mathrm{NN}}}=5.44$ TeV
• Statistics of initial density perturbations in heavy ion collisions and their fluid dynamic response
• Bayesian quantification of strongly-interacting matter with color glass condensate initial conditions
• Early-times Yang-Mills dynamics and the characterization of strongly interacting matter with statistical learning
• Mapping properties of the quark gluon plasma in Pb-Pb and Xe-Xe collisions at energies available at the CERN Large Hadron Collider

Cited by in corpus (4)

• Supercooled Goldstone Bosons at the QCD Chiral Phase Transition
• Quenching through the QCD chiral phase transition
• Nonequilibrium Phenomenology of Identified Particle Spectra in Heavy-Ion Collisions at LHC Energies
• Reconstructing rare particle source by femtoscopic correlations