By means of the AKK08 fragmentation function, the net-proton transverse momentum （pT） spectra in A＋A collisions are studied with two phenomenological models based on the Color Glass Condensate formalism. After a χ...By means of the AKK08 fragmentation function, the net-proton transverse momentum （pT） spectra in A＋A collisions are studied with two phenomenological models based on the Color Glass Condensate formalism. After a χ2 analysis of the experimental data from BRAHMS, the normalization constant C is extracted at RHIC energies of √sNN =62.4 and 200 GeV, and the theoretical results of the net-proton pT spectra at selected rapidities are also given. It is shown that the theoretical results are in good agreement with the experimental data. Finally, assuming the constant C should have an exponent dependence of √sNN, we also predict the theoretical results of net-proton pT spectra at LHC energies of √sNN = 2.76, 3.94, and 5.52 TeV.展开更多
It is proposed that ratios of the sixth order to the second order cumulant(C_(6)/C_(2))of conserved quantities are sensitive to the chiral crossover transition.Recently,the negative C_(6)/C_(2) was obtained in both th...It is proposed that ratios of the sixth order to the second order cumulant(C_(6)/C_(2))of conserved quantities are sensitive to the chiral crossover transition.Recently,the negative C_(6)/C_(2) was obtained in both theoretical Lattice QCD and experiments at■.In this study,we investigate the behavior of net-proton C_(6)/C_(2) in statistical Binomial distribution(BD)at■in Au+Au collisions.With the BD parameters extracted from RHIC/STAR,it is found that C_(6)/C_(2) can be negative.Furthermore,the obtained C_(6)/C_(2) becomes smaller when applying the same magnitude of experimental statistics and calculation method to simulations.In 0-10%centrality,there is a significant difference between the simulated result and theoretical expectation.Based on the extracted parameters and experimentally collected statistics,the baseline of net-proton C_(6)/C_(2) in BD is presented.展开更多
We perform a systematic study on the effect of non-uniform track efficiency correction in higher-order cumulant analysis in heavy-ion collisions.Through analytical derivation,we find that the true values of cumulants ...We perform a systematic study on the effect of non-uniform track efficiency correction in higher-order cumulant analysis in heavy-ion collisions.Through analytical derivation,we find that the true values of cumulants can be successfully reproduced by the efficiency correction with an average of the realistic detector efficiency for particles with the same charges within each single phase space.The theoretical conclusions are supported by a toy model simulation by tuning the non-uniformity of the efficiency employed in the track-by-track efficiency correction method.The valid averaged efficiency is found to suppress the statistical uncertainties of the reproduced cumulants dramatically.Thus,usage of the averaged efficiency requires a careful study of phase space dependence.This study is important for carrying out precision measurements of higher-order cumulants in heavy-ion collision experiments at present and in future.展开更多
基金Supported by Natural Science Foundation of Hebei Province (A2008000421)
文摘By means of the AKK08 fragmentation function, the net-proton transverse momentum （pT） spectra in A＋A collisions are studied with two phenomenological models based on the Color Glass Condensate formalism. After a χ2 analysis of the experimental data from BRAHMS, the normalization constant C is extracted at RHIC energies of √sNN =62.4 and 200 GeV, and the theoretical results of the net-proton pT spectra at selected rapidities are also given. It is shown that the theoretical results are in good agreement with the experimental data. Finally, assuming the constant C should have an exponent dependence of √sNN, we also predict the theoretical results of net-proton pT spectra at LHC energies of √sNN = 2.76, 3.94, and 5.52 TeV.
基金Supported by the postdoctral science and technology project of Hubei Province(2018Z27)the Fundamental Research Funds for the Central Universities(CCNU19ZN019)。
文摘It is proposed that ratios of the sixth order to the second order cumulant(C_(6)/C_(2))of conserved quantities are sensitive to the chiral crossover transition.Recently,the negative C_(6)/C_(2) was obtained in both theoretical Lattice QCD and experiments at■.In this study,we investigate the behavior of net-proton C_(6)/C_(2) in statistical Binomial distribution(BD)at■in Au+Au collisions.With the BD parameters extracted from RHIC/STAR,it is found that C_(6)/C_(2) can be negative.Furthermore,the obtained C_(6)/C_(2) becomes smaller when applying the same magnitude of experimental statistics and calculation method to simulations.In 0-10%centrality,there is a significant difference between the simulated result and theoretical expectation.Based on the extracted parameters and experimentally collected statistics,the baseline of net-proton C_(6)/C_(2) in BD is presented.
基金Supported by National Key Research and Development Program of China(2018YFE0205200,2018 YFE0104700,2020YFE0202002)Natural Science Foundation of China(11890711,11890712,12122505,11828501,11861131009)+1 种基金Anhui Provincial Natural Science Foundation(1808085J02)Innovation Fund of Key Laboratory of Quark and Lepton Physics(QLPL2020P01)。
文摘We perform a systematic study on the effect of non-uniform track efficiency correction in higher-order cumulant analysis in heavy-ion collisions.Through analytical derivation,we find that the true values of cumulants can be successfully reproduced by the efficiency correction with an average of the realistic detector efficiency for particles with the same charges within each single phase space.The theoretical conclusions are supported by a toy model simulation by tuning the non-uniformity of the efficiency employed in the track-by-track efficiency correction method.The valid averaged efficiency is found to suppress the statistical uncertainties of the reproduced cumulants dramatically.Thus,usage of the averaged efficiency requires a careful study of phase space dependence.This study is important for carrying out precision measurements of higher-order cumulants in heavy-ion collision experiments at present and in future.
