In the context of unified hydrodynamics, we discuss the pseudorapidity distributions of the charged particles produced in Au-Au and Cu-Cu collisions at the low RHIC energies of √SNN = 19.6 and 22.4 GeV, respectively....In the context of unified hydrodynamics, we discuss the pseudorapidity distributions of the charged particles produced in Au-Au and Cu-Cu collisions at the low RHIC energies of √SNN = 19.6 and 22.4 GeV, respectively. It is found that the unified hydrodynamics alone can give a good description to the experimental measurements. This is different from the collisions at the maximum RHIC energy of √SNN = 200 GeV or at LHC energy of √SNN= 2.76 TeV, in which the leading particles must be taken into account so that we can properly explain the experimental observations.展开更多
With the experimental data from STAR program on the centrality dependence of the PT spectra of charged hadron produced in d＋Au collisions at √^8NN=200 GeV, we show that there also exists a scaling distribution in th...With the experimental data from STAR program on the centrality dependence of the PT spectra of charged hadron produced in d＋Au collisions at √^8NN=200 GeV, we show that there also exists a scaling distribution in the backward rapidity regions. Using this scaling distribution, we get the theoretical psedorapidity asymmetry which is basically in agreement with STAR data in the regions of 0≤｜η｜≤0.5 and 0.5 ≤｜η｜≤1. No theoretical models are used in any part of this phenomenological analysis.展开更多
The longitudinal extension of interacting system in relativistic nucleus-nucleus colli-sions is considered.The pseudorapidity distribution of shower particles is described by the ther-realized cylinder picture.The cal...The longitudinal extension of interacting system in relativistic nucleus-nucleus colli-sions is considered.The pseudorapidity distribution of shower particles is described by the ther-realized cylinder picture.The calculated results are in agreement with the experimental data inthe incident energy region from 10~1 to 10~5 GeV/u.展开更多
The transverse momentum distributions of charged hadrons produced in proton-proton collisions at center-of-mass energies(√s)of 0.9 TeV and 2.36 TeV,as measured by the CMS detector at the Large Hadron Collider(LHC),ha...The transverse momentum distributions of charged hadrons produced in proton-proton collisions at center-of-mass energies(√s)of 0.9 TeV and 2.36 TeV,as measured by the CMS detector at the Large Hadron Collider(LHC),have been analyzed within various pseudorapidity classes utilizing the thermodynamically consistent Tsallis distribution.The fitting procedure resulted in the key parameters,namely,effective temperature(T),non-extensivity parameter(q),and kinetic freezeout volume(V).Additionally,the mean transverse momentum(<pT>)and initial temperature(T_(i))of the particle source are determined through the fit function and string percolation method,respectively.An alternative method is employed to calculate the kinetic freezeout temperature(T_(0))and transverse flow velocity(β_(T))from T.Furthermore,thermodynamic quantities at the freezeout,including energy density(ε),particle density(n),entropy density(s),pressure(P),and squared speed of sound(C_(s)^(2)),are computed using the extracted T and q.It is also observed that,with a decrease in pseudorapidity,all thermodynamic quantities except V and q increase.This trend is attributed to greater energy transfer along the mid pseudorapidity.q increases towards higher values of pseudorapidity,indicating that particles close to the beam axis are far from equilibrium.Meanwhile,V remains nearly independent of pseudorapidity.The excitation function of these parameters(q)shows a direct(inverse)correlation with collision energy.The ε,n,s,and P show a strong dependence on collision energies at low pseudorapidities.Explicit verification of the thermodynamic inequality ε≥3P suggests the formation of a highly dense droplet-like Quark-Gluon Plasma(QGP).Additionally,the inequality T_(i)>T>T_(0)is explicitly confirmed,aligning with the evolution of the produced fireball.展开更多
Using the Glauber model, we discuss the number of binary nucleon-nucleon collisions in heavy-ion collisions. Based on the latter, after considering the effect of energy loss of the nucleons in multiple collisions, we ...Using the Glauber model, we discuss the number of binary nucleon-nucleon collisions in heavy-ion collisions. Based on the latter, after considering the effect of energy loss of the nucleons in multiple collisions, we derive the pseudorapidity distribution of the multiplicity as a function of the impact parameter in nucleus-nucleus collisions. Using this, we analyze the experimental measurements carried out by the BRAHMS Collaboration in Au ＋ Au collisions at √^SNN=20GeV. The results are in good agreement with the experimental observations.展开更多
Using the Glauber model, we present the formulas for calculating the numbers of participants, spectators and binary nucleon-nucleon collisions. Based on this work, we get the pseudorapidity distributions of charged pa...Using the Glauber model, we present the formulas for calculating the numbers of participants, spectators and binary nucleon-nucleon collisions. Based on this work, we get the pseudorapidity distributions of charged particles as the function of the impact parameter in nucleus-nucleus collisions. The theoretical results agree well with the experimental observations made by the BRAHMS Collaboration in Au＋Au collisions at √^SNN=200 GeV in different centrality bins over the whole pseudorapidity range.展开更多
We investigate the effects of jet production on the following parameters： pseudorapidity, transverse momentum and transverse mass distributions of secondary charged particles produced in pp-collisions at 1.8 Te V,usi...We investigate the effects of jet production on the following parameters： pseudorapidity, transverse momentum and transverse mass distributions of secondary charged particles produced in pp-collisions at 1.8 Te V,using the HIJING code. These distributions are analyzed for the whole range and for six selected regions of the polar angle as a function of the different number of jets. The obtained simulation results for these parameters are interpreted and discussed in connection to the increase observed in the multiplicity of secondary charged particles as a result of its multi-jet dependence, and are also discussed in comparison with the experimental results from the CDF Collaboration.展开更多
The pseudorapidity spectra of fast particles （with β 〉 0.7） produced in Au （at 11.6 A GeV） and Pb （at 158 A GeV） induced collisions with emulsion （Em） nuclei contain some visual plateaus and shoulders. The p...The pseudorapidity spectra of fast particles （with β 〉 0.7） produced in Au （at 11.6 A GeV） and Pb （at 158 A GeV） induced collisions with emulsion （Em） nuclei contain some visual plateaus and shoulders. The plateau is wider for Pb＋Em reactions compared with the Au＋Em ones. The existence of a plateau is expected for parton models. The Fourier transformation and maximum entropy methods were used to get additional information about the plateaus. The dependence of the plateaus on the centrality of the collisions was also studied using the number of g-particles to fix centrality. It shows that the maximum entropy method could confirm the existence of the plateau and the shoulder on distributions.展开更多
By employing the Glauber model, we give the centrality dependences of the numbers of participants and binary nucleon-nucleon collisions in nucleus-nucleus collisions. By taking into account the energy loss of the part...By employing the Glauber model, we give the centrality dependences of the numbers of participants and binary nucleon-nucleon collisions in nucleus-nucleus collisions. By taking into account the energy loss of the participants in their multiple collisions, we then present the pseudorapidity distributions of charged particles in nucleus-nucleus collisions as a function of beam energy and impact parameter. Finally, we analyze the centrality dependence of the pseudorapidity of the charged particles in Au＋Au collisions at energies from √SNN=19.6 to 200 GeV. The theoretical results are in good agreement with the experimental observations of the RHIC-PHOBOS collaboration.展开更多
In the context of the combined model of evolution-dominated hydrodynamics ＋ leading particles, we discuss the pseudorapidity distributions of charged particles produced in p-p collisions. A comparison is made between...In the context of the combined model of evolution-dominated hydrodynamics ＋ leading particles, we discuss the pseudorapidity distributions of charged particles produced in p-p collisions. A comparison is made between the theoretical predictions and experimental measurements. The combined model works well in p-p collisions in the whole available energy region from √s=23.6 to 900 GeV.展开更多
In p-p collisions, the charged particles produced consist of two leading particles and those frozen out from the hot and dense matter created in the collisions. The two leading particles are in the projectile and targ...In p-p collisions, the charged particles produced consist of two leading particles and those frozen out from the hot and dense matter created in the collisions. The two leading particles are in the projectile and target fragmentation regions, respectively, which, in this paper, are conventionally supposed to have Gaussian rapidity distributions. The hot and dense matter is assumed to expand according to unified hydrodynamics, a hydrodynamic model which unifies the features of the Landau and Hwa-Bjorken models, and freeze out into charged particles from a space-like hypersurface with a fixed proper time of TFo. The rapidity distribution of these charged particles can be derived analytically. The combined contribution from both leading particles and unified hydrodynamics is then compared against experimental data from a now available center-of-mass energy region from 23.6 to 7000 GeV. The model predictions are consistent with experimental measurements.展开更多
The revised Landau hydrodynamic model is used to discuss the pseudorapidity distributions of the produced charged particles in Au＋Au and Cu＋Cu collisions at energies of s √SNN=19.6 and 22.4 GeV respectively at the ...The revised Landau hydrodynamic model is used to discuss the pseudorapidity distributions of the produced charged particles in Au＋Au and Cu＋Cu collisions at energies of s √SNN=19.6 and 22.4 GeV respectively at the BNL Relativistic Heavy Ion Collider. It is found that the revised Landau hydrodynamic model alone can give a good description of the experimental measurements. This is different from the result with the same collisions but at the maximum energy of√SNN=200 GeV, where in addition to the revised Landau hydrodynamic model, the effects of leading particles have to be taken into account in order to explain the experimental observations. This can be attributed to the different degrees of transparency of participants at the different incident energies.展开更多
The energy and centrality dependencies of charged particle pseudorapidity density in relativistic nuclear collisions were studied using a hadron and string cascade model, JPCIAE. Both the relativistic experimental da...The energy and centrality dependencies of charged particle pseudorapidity density in relativistic nuclear collisions were studied using a hadron and string cascade model, JPCIAE. Both the relativistic experimental data and the PHOBOS and PHENIX Au+Au data at RHIC energy could be fairly reproduced within the framework of JPCIAE model and without retuning the model parameters. The predictions for collisions at the LHC energy were also given. We computed the participant nucleon distributions using different methods. It was found that the number of participant nucleons is not a well defined variable both experimentally and theoretically. Thus it may be inappropriate to use the charged particle pseudorapidity density per participant pair as a function of the number of participant nucleons for distinguishing various theoretical models.展开更多
A multifractal analysis to study the multiparticle dynamics in 60A and 200A GeV, 16O-AgBr collisions has been performed in the pseudorapidity phase space. Multifractal moments, Gq, as the function of pseudorapidity bi...A multifractal analysis to study the multiparticle dynamics in 60A and 200A GeV, 16O-AgBr collisions has been performed in the pseudorapidity phase space. Multifractal moments, Gq, as the function of pseudorapidity bin size for different order of the moments, q, have been calculated. The power-law behaviour has been observed in the considered data sets. The variations of multifractal dimension, Dq, and the multifractal spectral function, f(aq), with order of the moments, q, have been studied thoroughly. Dq is found to decrease with increasing order of moments, q, indicating thereby a self-similar behaviour in the multiparticle production for the considered collisions. We have also found a concave downward curve of multifractal spectral function with maximum at q = 0.展开更多
The charged-particle final state spectrum is derived from an analytic perturbative solution for relativistic viscous hydrodynamics. By taking into account the longitudinal acceleration effect in relativistic viscous h...The charged-particle final state spectrum is derived from an analytic perturbative solution for relativistic viscous hydrodynamics. By taking into account the longitudinal acceleration effect in relativistic viscous hydrody namics, the pseudorapidity spectrum describes the nucleus-nucleus colliding systems at RHIC and the LHC well. Based on both the extracted longitudinal acceleration parameter λ^＊ and a phenomenological description of λ^＊, the charged-particle pseudorapidity distributions for √SNN= 5.44 TeV Xe＋Xe collisions are computed from the final state expression in a limited space-time rapidity ~/8 region.展开更多
基金Supported by the Shanghai Key Lab of Modern Optical System
文摘In the context of unified hydrodynamics, we discuss the pseudorapidity distributions of the charged particles produced in Au-Au and Cu-Cu collisions at the low RHIC energies of √SNN = 19.6 and 22.4 GeV, respectively. It is found that the unified hydrodynamics alone can give a good description to the experimental measurements. This is different from the collisions at the maximum RHIC energy of √SNN = 200 GeV or at LHC energy of √SNN= 2.76 TeV, in which the leading particles must be taken into account so that we can properly explain the experimental observations.
基金National Natural Science Foundation of China under Grant No.10777577
文摘With the experimental data from STAR program on the centrality dependence of the PT spectra of charged hadron produced in d＋Au collisions at √^8NN=200 GeV, we show that there also exists a scaling distribution in the backward rapidity regions. Using this scaling distribution, we get the theoretical psedorapidity asymmetry which is basically in agreement with STAR data in the regions of 0≤｜η｜≤0.5 and 0.5 ≤｜η｜≤1. No theoretical models are used in any part of this phenomenological analysis.
基金The project supported by Shanxi Provincial Foundation of Leading Man in Science,Shanxi Proyincial Foundation of Scholarly Exchange and China National Education Committee Foundation of Scholarly Exchange
文摘The longitudinal extension of interacting system in relativistic nucleus-nucleus colli-sions is considered.The pseudorapidity distribution of shower particles is described by the ther-realized cylinder picture.The calculated results are in agreement with the experimental data inthe incident energy region from 10~1 to 10~5 GeV/u.
基金Supported by Princess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2024R106), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabiathe authors extend their appreciation to the Deanship of Scientific Research at Northern Border University, Arar, KSA for funding this research work through the project number “NBU-FFR-2024-2461-04”University,Riyadh,Saudi Arabia.In addition,the authors extend their appreciation to the Deanship of Scientific Research at Northern Border University,Arar,KSA for funding this research work through the project number“NBU-FFR-2024-2461-04”。
文摘The transverse momentum distributions of charged hadrons produced in proton-proton collisions at center-of-mass energies(√s)of 0.9 TeV and 2.36 TeV,as measured by the CMS detector at the Large Hadron Collider(LHC),have been analyzed within various pseudorapidity classes utilizing the thermodynamically consistent Tsallis distribution.The fitting procedure resulted in the key parameters,namely,effective temperature(T),non-extensivity parameter(q),and kinetic freezeout volume(V).Additionally,the mean transverse momentum(<pT>)and initial temperature(T_(i))of the particle source are determined through the fit function and string percolation method,respectively.An alternative method is employed to calculate the kinetic freezeout temperature(T_(0))and transverse flow velocity(β_(T))from T.Furthermore,thermodynamic quantities at the freezeout,including energy density(ε),particle density(n),entropy density(s),pressure(P),and squared speed of sound(C_(s)^(2)),are computed using the extracted T and q.It is also observed that,with a decrease in pseudorapidity,all thermodynamic quantities except V and q increase.This trend is attributed to greater energy transfer along the mid pseudorapidity.q increases towards higher values of pseudorapidity,indicating that particles close to the beam axis are far from equilibrium.Meanwhile,V remains nearly independent of pseudorapidity.The excitation function of these parameters(q)shows a direct(inverse)correlation with collision energy.The ε,n,s,and P show a strong dependence on collision energies at low pseudorapidities.Explicit verification of the thermodynamic inequality ε≥3P suggests the formation of a highly dense droplet-like Quark-Gluon Plasma(QGP).Additionally,the inequality T_(i)>T>T_(0)is explicitly confirmed,aligning with the evolution of the produced fireball.
文摘Using the Glauber model, we discuss the number of binary nucleon-nucleon collisions in heavy-ion collisions. Based on the latter, after considering the effect of energy loss of the nucleons in multiple collisions, we derive the pseudorapidity distribution of the multiplicity as a function of the impact parameter in nucleus-nucleus collisions. Using this, we analyze the experimental measurements carried out by the BRAHMS Collaboration in Au ＋ Au collisions at √^SNN=20GeV. The results are in good agreement with the experimental observations.
基金Supported by Key Foundation of Shanghai (S30501)
文摘Using the Glauber model, we present the formulas for calculating the numbers of participants, spectators and binary nucleon-nucleon collisions. Based on this work, we get the pseudorapidity distributions of charged particles as the function of the impact parameter in nucleus-nucleus collisions. The theoretical results agree well with the experimental observations made by the BRAHMS Collaboration in Au＋Au collisions at √^SNN=200 GeV in different centrality bins over the whole pseudorapidity range.
基金Supported by Higher Education Commission(HEC)Government of Pakistan under Indigenous5000 PhD Scholarship Program Batch-IV
文摘We investigate the effects of jet production on the following parameters： pseudorapidity, transverse momentum and transverse mass distributions of secondary charged particles produced in pp-collisions at 1.8 Te V,using the HIJING code. These distributions are analyzed for the whole range and for six selected regions of the polar angle as a function of the different number of jets. The obtained simulation results for these parameters are interpreted and discussed in connection to the increase observed in the multiplicity of secondary charged particles as a result of its multi-jet dependence, and are also discussed in comparison with the experimental results from the CDF Collaboration.
基金Supported by Scientific Agency of the Ministry of Education of the Slovak Republic and the Slovak Academy of Sciences (1/0080/08) and from the HEC Pakistangrants from the Plenipotentiary of Slovak Republic at the JINR (Dubna) in 2010-2011
文摘The pseudorapidity spectra of fast particles （with β 〉 0.7） produced in Au （at 11.6 A GeV） and Pb （at 158 A GeV） induced collisions with emulsion （Em） nuclei contain some visual plateaus and shoulders. The plateau is wider for Pb＋Em reactions compared with the Au＋Em ones. The existence of a plateau is expected for parton models. The Fourier transformation and maximum entropy methods were used to get additional information about the plateaus. The dependence of the plateaus on the centrality of the collisions was also studied using the number of g-particles to fix centrality. It shows that the maximum entropy method could confirm the existence of the plateau and the shoulder on distributions.
基金Supported by Key Foundation of Shanghai (S30501)
文摘By employing the Glauber model, we give the centrality dependences of the numbers of participants and binary nucleon-nucleon collisions in nucleus-nucleus collisions. By taking into account the energy loss of the participants in their multiple collisions, we then present the pseudorapidity distributions of charged particles in nucleus-nucleus collisions as a function of beam energy and impact parameter. Finally, we analyze the centrality dependence of the pseudorapidity of the charged particles in Au＋Au collisions at energies from √SNN=19.6 to 200 GeV. The theoretical results are in good agreement with the experimental observations of the RHIC-PHOBOS collaboration.
基金Supported by Transformation Project of Science and Technology of Shanghai Baoshan District(CXY-2012-25)Shanghai Leading Academic Discipline Project(XTKX 2012)+1 种基金National Training Project(14XPM03)the Hujiang Foundation of China(B14004)
文摘In the context of the combined model of evolution-dominated hydrodynamics ＋ leading particles, we discuss the pseudorapidity distributions of charged particles produced in p-p collisions. A comparison is made between the theoretical predictions and experimental measurements. The combined model works well in p-p collisions in the whole available energy region from √s=23.6 to 900 GeV.
基金Supported by Hujiang Foundation of China(B14004)Shanghai Key Lab of Modern Optical System
文摘In p-p collisions, the charged particles produced consist of two leading particles and those frozen out from the hot and dense matter created in the collisions. The two leading particles are in the projectile and target fragmentation regions, respectively, which, in this paper, are conventionally supposed to have Gaussian rapidity distributions. The hot and dense matter is assumed to expand according to unified hydrodynamics, a hydrodynamic model which unifies the features of the Landau and Hwa-Bjorken models, and freeze out into charged particles from a space-like hypersurface with a fixed proper time of TFo. The rapidity distribution of these charged particles can be derived analytically. The combined contribution from both leading particles and unified hydrodynamics is then compared against experimental data from a now available center-of-mass energy region from 23.6 to 7000 GeV. The model predictions are consistent with experimental measurements.
基金Supported by Transformation Project of Science and Technology of Shanghai Baoshan District(CXY-2012-25)Shanghai Leading Academic Discipline Project(XTKX 2012)
文摘The revised Landau hydrodynamic model is used to discuss the pseudorapidity distributions of the produced charged particles in Au＋Au and Cu＋Cu collisions at energies of s √SNN=19.6 and 22.4 GeV respectively at the BNL Relativistic Heavy Ion Collider. It is found that the revised Landau hydrodynamic model alone can give a good description of the experimental measurements. This is different from the result with the same collisions but at the maximum energy of√SNN=200 GeV, where in addition to the revised Landau hydrodynamic model, the effects of leading particles have to be taken into account in order to explain the experimental observations. This can be attributed to the different degrees of transparency of participants at the different incident energies.
文摘The energy and centrality dependencies of charged particle pseudorapidity density in relativistic nuclear collisions were studied using a hadron and string cascade model, JPCIAE. Both the relativistic experimental data and the PHOBOS and PHENIX Au+Au data at RHIC energy could be fairly reproduced within the framework of JPCIAE model and without retuning the model parameters. The predictions for collisions at the LHC energy were also given. We computed the participant nucleon distributions using different methods. It was found that the number of participant nucleons is not a well defined variable both experimentally and theoretically. Thus it may be inappropriate to use the charged particle pseudorapidity density per participant pair as a function of the number of participant nucleons for distinguishing various theoretical models.
文摘A multifractal analysis to study the multiparticle dynamics in 60A and 200A GeV, 16O-AgBr collisions has been performed in the pseudorapidity phase space. Multifractal moments, Gq, as the function of pseudorapidity bin size for different order of the moments, q, have been calculated. The power-law behaviour has been observed in the considered data sets. The variations of multifractal dimension, Dq, and the multifractal spectral function, f(aq), with order of the moments, q, have been studied thoroughly. Dq is found to decrease with increasing order of moments, q, indicating thereby a self-similar behaviour in the multiparticle production for the considered collisions. We have also found a concave downward curve of multifractal spectral function with maximum at q = 0.
基金Supported by National Natural Science Foundation of China(11435004)the Chinese-Hungarian bilateral cooperation program(Te’T12CN-1-2012-0016)the CCNU PhD Fund 2016YBZZ100 of China
文摘The charged-particle final state spectrum is derived from an analytic perturbative solution for relativistic viscous hydrodynamics. By taking into account the longitudinal acceleration effect in relativistic viscous hydrody namics, the pseudorapidity spectrum describes the nucleus-nucleus colliding systems at RHIC and the LHC well. Based on both the extracted longitudinal acceleration parameter λ^＊ and a phenomenological description of λ^＊, the charged-particle pseudorapidity distributions for √SNN= 5.44 TeV Xe＋Xe collisions are computed from the final state expression in a limited space-time rapidity ~/8 region.
