Examination of background effects on light-nuclei yield ratio in relativistic heavy-ion collisions

Abstract

The light-nuclei yield ratio is one of the candidates to probe the critical fluctuations of hot QCD matter. In this paper, we investigate the \textit{background effects}, namely the non-critical effects coming from the non-trivial thermal background, on the light-nuclei production within the framework of the coalescence model. Specifically, we analyze the impact of the equilibrium phase-space distribution function of nucleons, $f(\mathbf{r},\mathbf{p})$, on the light-nuclei yield ratio $N_t{N}_p/N_d^2$, where $N_t$, $N_p$, and $N_d$ denote triton, proton, and deuteron yields. By considering the characteristic function of the phase-space distribution, we systematically expand the yield of light nuclei of $A$-constituent nucleons, $N_A$, in terms of the \textit{phase-space cumulants}, $⟨{\mathbf{r}}^n{\mathbf{p}}^m{⟩}_c$. We find that the cumulants up to the second-order are canceled out in the generalized ratio $N_p^{B-A}{N}_B^{A-1}/N_A^{B-1}$. This means that the dominant background effects including the fireball size, the kinetic freeze-out temperature, and the coordinate--momentum correlations caused by the radial expansion play an insignificant role in the yield ratio, which supports the yield ratio as a useful tool for the critical-point search. We also show several examples of background phase-space distributions for the qualitative illustration. The higher-order cumulants, which correspond to the non-Gaussian shape of the phase-space profile, play an important role in the variation of the yield ratio particularly for the smaller fireball sizes. Qualitatively, the spatial structure of the background decreases the yield ratio, and the azimuthal anisotropy $v_n$ increases it. The higher order of the azimuthal anisotropy causes a larger effect on the yield ratio. These results call for the comprehensive future studies of the yield ratio using sophisticated dynamical models.

arXiv commentv2:title changed, Fig.1 modified, published on PRC

References in corpus (76)

• The order of the quantum chromodynamics transition predicted by the standard model of particle physics
• Dyson-Schwinger Equations and the Application to Hadronic Physics
• Signatures of the Tricritical Point in QCD
• Chiral effective model with the Polyakov loop
• Radial and elliptic flow at RHIC: further predictions
• Aspects of the Functional Renormalisation Group
• Event-by-Event Fluctuations in Heavy Ion Collisions and the QCD Critical Point
• Decoding the phase structure of QCD via particle production at high energy
• Non-Gaussian fluctuations near the QCD critical point
• The Phase Structure of the Polyakov--Quark-Meson Model
• Mapping the Phases of Quantum Chromodynamics with Beam Energy Scan
• On the sign of kurtosis near the QCD critical point
• Search for the QCD Critical Point with Fluctuations of Conserved Quantities in Relativistic Heavy-Ion Collisions at RHIC : An Overview
• Coalescence and flow in ultra-relativistic heavy ion collisions
• Production of light nuclei and anti-nuclei in pp and Pb-Pb collisions at LHC energies
• Third moments of conserved charges as probes of QCD phase structure
• Non-monotonic energy dependence of net-proton number fluctuations
• Hydro+: hydrodynamics with parametric slowing down and fluctuations near the critical point
• Phase diagram and critical endpoint for strongly-interacting quarks
• Lattice QCD and heavy ion collisions: a review of recent progress
• 2+1 Flavor Polyakov--Nambu--Jona-Lasinio Model at Finite Temperature and Nonzero Chemical Potential
• Using Higher Moments of Fluctuations and their Ratios in the Search for the QCD Critical Point
• Relation between baryon number fluctuations and experimentally observed proton number fluctuations in relativistic heavy ion collisions
• Cumulants and Correlation Functions of Net-proton, Proton and Antiproton Multiplicity Distributions in Au+Au Collisions at energies available at the BNL Relativistic Heavy Ion Collider
• Light cluster production in intermediate energy heavy-ion collisions induced by neutron-rich nuclei
• Revealing baryon number fluctuations from proton number fluctuations in relativistic heavy ion collisions
• Studying Exotic Hadrons in Heavy Ion Collisions
• Light nuclei quasiparticle energy shift in hot and dense nuclear matter
• Nuclear Clusters as a Probe for Expansion Flow in Heavy Ion Reactions at 10-15AGeV
• Loosely-bound objects produced in nuclear collisions at the LHC
• Probing QCD critical fluctuations from light nuclei production in relativistic heavy-ion collisions
• Light nuclei production as a probe of the QCD phase diagram
• Fluctuations of conserved charges in relativistic heavy ion collisions: An introduction
• Beam energy dependence of (anti-)deuteron production in Au+Au collisions at RHIC
• Suppression of light nuclei production in collisions of small systems at the Large Hadron Collider
• Acceptance dependence of fluctuation measures near the QCD critical point
• Cosmic rays, anti-helium, and an old navy spotlight
• Production of deuterium, tritium, and ${}^3$He in central Pb+Pb collisions at 20A, 30A, 40A, 80A, and 158A GeV at the CERN SPS
• Multiplicity dependence of light nuclei production at LHC energies in the canonical statistical model
• Centrality dependence of proton and antiproton spectra in Pb+Pb collisions at 40A GeV and 158A GeV measured at the CERN SPS
• Testing coalescence and statistical-thermal production scenarios for (anti-)(hyper-)nuclei and exotic QCD objects at energies available at the CERN Large Hadron Collider
• Light (anti-)nuclei production and flow in relativistic heavy-ion collisions
• Spectra and flow of light nuclei in relativistic heavy ion collisions at RHIC and the LHC
• Transits of the QCD Critical Point
• Nuclear coalescence from correlation functions
• Correlated fluctuations near the QCD critical point
• Centrality and Energy Dependence of Proton, Light Fragment and Hyperon Production
• Fluctuation dynamics near the QCD critical point
• Baryon preclustering at the freeze-out of heavy-ion collisions and light-nuclei production
• Light Nuclei Production in Au+Au Collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5-200 GeV from JAM model
• Deuteron production in AuAu collisions at $\sqrt{s_{NN}}=7-200$ GeV via pion catalysis
• On coalescence as the origin of nuclei in hadronic collisions
• Beam Energy dependence of Light Nuclei Production in Au+Au Collisions
• Production of antimatter ${}^{5,6}$Li nuclei in central Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV
• Production of light nuclei at colliders -- coalescence vs. thermal model
• Light nuclei production in relativistic heavy ion collisions from the AMPT model
• Production of Light Nuclei at Thermal Freezeout in Heavy-Ion Collisions
• Coalescence, the thermal model and multi-fragmentation: The energy and volume dependence of light nuclei production in heavy ion collisions
• Dynamical exploring the QCD matter at finite temperatures and densities-a short review
• Feeddown contributions from unstable nuclei in relativistic heavy-ion collisions
• Overview of light nuclei production in relativistic heavy-ion collisions
• Light nuclei production in Au + Au collisions at $\sqrt{s_{NN}}$ = 7.7-80 GeV from UrQMD model
• Effects of QCD critical point on light nuclei production
• Deuterons and space-momentum correlations in high energy nuclear collisions
• HBT interferometry relative to the triangular flow plane in heavy-ion collisions
• Enhanced yield ratio of light nuclei in heavy ion collisions with a first-order QCD phase transition
• Yield ratio of hypertriton to light nuclei in heavy-ion collisions from $\sqrt{{\mathrm{s}}_{\mathrm{NN}}}$ = 4.9 GeV to 2.76 TeV
• Understanding the energy dependence of $B_2$ in heavy ion collisions: Interplay of volume and space-momentum correlations
• The QCD critical point hunt: emergent new ideas and new dynamics
• Deuteron and Antideuteron Coalescence in Heavy-Ion Collisions: Energy Dependence of the Formation Geometry
• Momentum dependence of light nuclei production in pp, p-Pb and Pb-Pb collisions at the CERN Large Hadron Collider
• Energy Dependence of Light Nuclei ($d$, $t$) Production at STAR
• Probing the properties of event-by-event distributions in Hanbury-Brown--Twiss radii
• Universal scaling of conserved charge in the stochastic diffusion dynamics
• Many-body forces and nucleon clustering near the QCD critical point
• Nucleon clustering at kinetic freezeout of heavy-ion collisions via path-integral Monte Carlo

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