arXiv subjects

Hai-Ling Lao

Publications and source records attributed to Hai-Ling Lao.

12 recordsLinked to original sources

arXiv2026

Fragmentation of Nuclear Remnants in Electron-Nucleus Collisions at High Energy as a Nonextensive Process

Utilizing a partitioning method based on equal (or unequal) probabilities -- without incorporating the alpha-cluster ($α$-cluster) model -- allows for the derivation of diverse topological configurations of nuclear fragments resulting from fragmentation. Subsequently, we predict the multiplicity distribution of nuclear fragments for specific excited nuclei, such as $^9$Be$^*$, $^{12}$C$^*$, and $^{16}$O$^*$, which can be formed as nuclear remnants in electron-nucleus ($eA$) collisions at high energy. Based on the $α$-cluster model, an $α$-cluster structure may result in deviations in the multiplicity distributions of nuclear fragments with charge $Z=2$, compared to those predicted by the partitioning methods. Furthermore, in the framework of Tsallis statistics, the nonextensive generalized temperature, entropy index, and $q$-entropy are obtained from the multiplicity distribution of nuclear fragments with given charge number. Our work shows that fragmentation of nuclear remnants in electron-nucleus collisions at high energy is a nonextensive process.

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arXiv2025

A hybrid model for multi-particle production and multi-fragment emission in electron-nucleus collisions at the forthcoming Electron-Ion Collider

To present a prediction of the multi-particle production and multi-fragment emission in electron-nucleus ($eA$) collisions at the forthcoming Electron-Ion Collider (EIC), a simple hybrid model which is based on the multi-source thermal model and the ideal gas model is proposed in this article. According to the hybrid model, some statistical laws such as the two-component Erlang distribution and others are presented, which means a two-source production. These statistical laws are hopeful to describe the bulk properties of multiple particles produced in the scattering of electron-nucleon ($eN$) and multiple fragments emitted in the fragmentation of excited residual nucleus. Although both the scattering and fragmentation can occur in $eA$ collisions at the EIC, their two-sources are different. In $eN$ scattering, the multiple particles come from the soft excitation and hard scattering processes respectively, which are classified as two different types of events. In nuclear fragmentation, the multiple fragments come from the cold and hot sources which exist in the same excited nucleus.

hep-ph↗

arXiv2025

On Extracting Thermal Parameters and Scenario in High-Energy Collisions

In this minireview article, we examine the inconsistent results of thermal parameters derived from various models in high-energy collisions. Through a comprehensive literature review and based on the average transverse momentum or the root-mean-square transverse momentum, we propose model-independent parameters to address these inconsistencies. The relevant parameters include: the initial temperature, the effective temperature, the kinetic freeze-out temperature, and the average transverse velocity. Our findings indicate that these four parameters are larger in central collisions, within central rapidity regions, at higher energies, and in larger collision systems. As collision energy increases, excitation functions for all four parameters rise rapidly (slowly) within ranges below (above) approximately 7.7 GeV. At higher energies (>39) GeV, fluctuations occur in trends for these excitation functions, with only slight changes observed in their growth rates. Additionally, this work reveals a mass-dependent multi-temperature scenario pertaining to both initial states and kinetic freeze-out processes.

hep-ph↗

arXiv2024

Comparing effective temperatures in standard, Tsallis, and q-dual statistics from transverse momentum spectra of identified light charged hadrons produced in gold--gold collisions at RHIC energies

This study investigates the transverse momentum ($p_T$) spectra of identified light charged hadrons produced in gold--gold (Au+Au) collisions across various centrality classes at center-of-mass energies per nucleon pair, $\sqrt{s_{NN}}$, ranging from 7.7 to 200 GeV, as measured by the STAR Collaboration at the Relativistic Heavy Ion Collider (RHIC). The analysis employs standard (Bose-Einstein/Fermi-Dirac), Tsallis, and q-dual statistics to fit the same $p_T$ spectra and derive distinct effective temperatures: $T_{\text{Standard}}$, $T_{\text{Tsallis}}$, and $T_{\text{q-dual}}$. In most instances, there exists an approximately linear relationship or positive correlation between $T_{\text{Tsallis}}$ and $T_{\text{Standard}}$, as well as between $T_{\text{q-dual}}$ and $T_{\text{Standard}}$, when considering $T_{\text{Standard}}$ as a baseline. However, while both $T_{\text{Tsallis}}$ and $T_{\text{q-dual}}$ increase from semi-central to central Au+Au collisions at 62.4 GeV and 200 GeV, where QGP is expected, changes in $T_{\text{Standard}}$ occur more gradually. This work suggests that $T_{\text{Standard}}$ is better suited for characterizing phase transitions between hadronic matter and QGP compared to $T_{\text{Tsallis}}$ or $T_{\text{q-dual}}$, primarily due to the considerations related to entropy index in the Tsallis and q-dual statistics.

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arXiv2019

Light particle and quark chemical potentials from negatively to positively charged particle yield ratios corrected by removing strong and weak decays

The yield ratios of negatively to positively charged pions ($π^-/π^+$), negatively to positively charged kaons ($K^-/K^+$), and anti-protons to protons ($\bar p/p$) produced in mid-rapidity interval in central gold-gold (Au-Au) collisions, central lead-lead (Pb-Pb) collisions, and inelastic (INEL) or non-single-diffractive (NSD) proton-proton ($pp$) collisions, as well as in forward rapidity region in INEL $pp$ collisions are analyzed in the present work. Over an energy range from a few GeV to above 10 TeV, the chemical potentials of light flavor particles (pion, kaon, and proton) and quarks (up, down, and strange quarks) are extracted from the mentioned yield ratios in which the contributions of strong decay from high-mass resonance and weak decay from heavy flavor hadrons are removed. Most energy dependent chemical potentials show the maximum at about 4 GeV, while the energy dependent yield ratios do not show such an extremum.

hep-ph↗

arXiv2019

Energy dependent chemical potentials of light particles and quarks from yield ratios of antiparticles to particles in high energy collisions

We collect the yields of charged pions ($π^-$ and $π^+$), charged kaons ($K^-$ and $K^+$), anti-protons ($\bar p$), and protons ($p$) produced in mid-rapidity interval (in most cases) in central gold-gold (Au-Au), central lead-lead (Pb-Pb), and inelastic or non-single-diffractive proton-proton ($pp$) collisions at different collision energies. The chemical potentials of light particles and quarks are extracted from the yield ratios, $π^-/π^+$, $K^-/K^+$, and $\bar p/p$, of antiparticles to particles over an energy range from a few GeV to above 10 TeV. At a few GeV ($\sim4$ GeV), the chemical potentials show, and the yield ratios do not show, different trends comparing with those at other energies, though the limiting values of the chemical potentials and the yield ratios at very high energy are 0 and 1 respectively.

hep-ph↗

arXiv2018

Chemical potentials of light flavor quarks from yield ratios of negative to positive particles in Au+Au collisions at RHIC

The transverse momentum spectra of $π^{-}$, $π^{+}$, $K^{-}$, $K^{+}$, $\bar{p}$, and $p$ produced in Au+Au collisions at center-of-mass energy $\sqrt{s_{NN}}=7.7$, 11.5, 19.6, 27, 39, 62.4, 130, and $200$ GeV are analyzed in the framework of a multisource thermal model. The experimental data measured at midrapidity by the STAR Collaboration are fitted by the (two-component) standard distribution. The effective temperature of emission source increases obviously with the increase of the particle mass and the collision energy. At different collision energies, the chemical potentials of up, down, and strange quarks are obtained from the antiparticle to particle yield ratios in given transverse momentum ranges available in experiments. With the increase of logarithmic collision energy, the chemical potentials of light flavor quarks decrease exponentially.

nucl-th↗

arXiv2018

Examining the model dependence of the determination of kinetic freeze-out temperature and transverse flow velocity in small collision system

The transverse momentum distributions of the identified particles produced in small collision systems at the Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) have been analyzed by four models. The first two models utilize the blast-wave model with different statistics. The last two models employ certain linear correspondences based on different distributions. The four models describe the experimental data measured by the Pioneering High Energy Nuclear Interaction eXperiment (PHENIX), Solenoidal Tracker at RHIC (STAR), and A Large Ion Collider Experiment (ALICE) cCollaborations equally well. It is found that both the kinetic freeze-out temperature and transverse flow velocity in the central collisions are comparable with those in the peripheral collisions. With the increase of collision energy from that of the RHIC to that of the LHC, the considered quantities typically do not decrease. Comparing with the central collisions, the proton-proton collisions are closer to the peripheral collisions.

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arXiv2018

Kinetic freeze-out temperatures in central and peripheral collisions: Which one is larger?

The kinetic freeze-out temperatures, $T_0$, in nucleus-nucleus collisions at the Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies are extracted by four methods: i) the Blast-Wave model with Boltzmann-Gibbs statistics (the BGBW model), ii) the Blast-Wave model with Tsallis statistics (the TBW model), iii) the Tsallis distribution with flow effect (the improved Tsallis distribution), and iv) the intercept in $T=T_0+am_0$ (the alternative method), where $m_0$ denotes the rest mass and $T$ denotes the effective temperature which can be obtained by different distribution functions. It is found that the relative sizes of $T_0$ in central and peripheral collisions obtained by the conventional BGBW model which uses a zero or nearly zero transverse flow velocity, $β_T$, are contradictory in tendency with other methods. With a re-examination for $β_T$ in the first method in which $β_T$ is taken to be $\sim(0.40\pm0.07)c$, a recalculation presents a consistent result with others. Finally, our results show that the kinetic freeze-out temperature in central collisions is larger than that in peripheral collisions.

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arXiv2017

Extracting kinetic freeze-out temperature and radial flow velocity from an improved Tsallis distribution

We analyze the transverse momentum ($p_T$) spectra of identified particles ($π^{\pm}$, $K^{\pm}$, $p$, and $\bar p$) produced in gold-gold (Au-Au) and lead-lead (Pb-Pb) collisions over a $\sqrt{s_{NN}}$ (center-of-mass energy per nucleon pair) range from 14.5 GeV [one of the Relativistic Heavy Ion Collider (RHIC) energies] to 2.76 TeV [one of the Large Hadron Collider (LHC) energies]. For the spectra with a narrow $p_T$ range, an improved Tsallis distribution which is in fact the Tsallis distribution with radial flow is used. For the spectra with a wide $p_T$ range, a superposition of the improved Tsallis distribution and an inverse power-law is used. Both the extracted kinetic freeze-out temperature ($T_0$) and radial flow velocity ($β_T$) increase with the increase of $\sqrt{s_{NN}}$, which indicates a higher excitation and larger expansion of the interesting system at the LHC. Both the values of $T_0$ and $β_T$ in central collisions are slightly larger than those in peripheral collisions, and they are independent of isospin and slightly dependent on mass.

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arXiv2016

An Evidence of Mass Dependent Differential Kinetic Freeze-out Scenario Observed in Pb-Pb Collisions at 2.76 TeV

Transverse momentum spectra of different particles produced in mid-rapidity interval in lead-lead (Pb-Pb) collisions with different centrality intervals, measured by the ALICE Collaboration at center-of-mass energy per nucleon pair $\sqrt{s_{NN}}=2.76$ TeV, are conformably and approximately described by the Tsallis distribution. The dependences of parameters (effective temperature, entropy index, and normalization factor) on event centrality and particle rest mass are obtained. The source temperature at the kinetic freeze-out is obtained to be the intercept in the linear relation between effective temperature and particle rest mass, while the particle transverse flow velocity is approximately extracted to be the slope in the linear relation between mean transverse momentum and particle rest mass. It is shown that the source temperature increases with increase of particle rest mass, which exhibits an evidence of mass dependent differential kinetic freeze-out scenario or multiple kinetic freeze-out scenario.

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arXiv2016

Productions of J/psi mesons in p-Pb collisions at 5 TeV

The rapidity distributions of $J/ψ$ mesons produced in proton-lead ($p$-Pb) collisions at center-of-mass energy per nucleon pair $\sqrt{s_{NN}}=5$ TeV are studied by using a multisource thermal model and compared with the experimental data of the LHCb and ALICE Collaborations. Correspondingly, the pseudorapidity distributions are accurately obtained from the parameters extracted from the rapidity distributions. At the same time, the transverse momentum distributions in the same experiments are described by the simplest Erlang distribution which is the folding result of two exponential distributions which are contributed by the target and projectile partons respectively.

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