We present a systematic study of the elliptic flow v_(2) relative to the participant plane(PP)and reaction plane(RP)in Au+Au collisions at√SNN=7.7-200 Ge V using the AMPT model(string melting version).The ratio v_(2)...We present a systematic study of the elliptic flow v_(2) relative to the participant plane(PP)and reaction plane(RP)in Au+Au collisions at√SNN=7.7-200 Ge V using the AMPT model(string melting version).The ratio v_(2)^(PP)/v_(2)^(RP)is investigated under different hadronic cascade times(0.6 fm/c,10 fm/c,and the maximum evolution time)and across various collision centralities.The results show that,at a fixed collision energy,the ratio exhibits negligible sensitivity to the duration of the hadronic rescattering stage,indicating that hadronic interactions have a minimal effect on the relative difference generated by initial-state fluctuations.However,a strong energy dependence is observed:the ratio increases with beam energy and saturates above√SNN≈62.4GeV,a trend that persists across all centralities.These findings highlight the dominant role of the partonic phase in converting initial-state geometry fluctuations into final-state momentum anisotropy.Conversely,at lower energies,the reduced partonic interaction strength limits the efficiency of this conversion,weakening the system’s ability to preserve the initial geometric information.Our results suggest that the conversion of initial geometric fluctuations into final momentum anisotropy requires sufficient partonic interactions.展开更多
A detailed theoretical derivation of the cross sections of e^＋e^-→e^＋e^-and e^＋e^-→μ＋μ-around the J/ψ resonance is reported. The resonance and interference parts of the cross sections, related to J/ψ resonan...A detailed theoretical derivation of the cross sections of e^＋e^-→e^＋e^-and e^＋e^-→μ＋μ-around the J/ψ resonance is reported. The resonance and interference parts of the cross sections, related to J/ψ resonance parameters, are calculated. Higher-order corrections for vacuum polarization and initial-state radiation are considered. An arbitrary upper limit of radiative correction integration is involved. Full and simplified versions of analytic formulae are given with precision at the level of 0.1% and 0.2%, respectively. Moreover, the results obtained in the paper can be applied to the case of the ψ（3686） resonance.展开更多
Recent LHC results on the appearance of sub-leading flow modes in Pb Pb collisions at 2.76 TeV, related to initial-state fluctuations, are analyzed and interpreted within the HYDJET＋＋ model. Using the newly introduc...Recent LHC results on the appearance of sub-leading flow modes in Pb Pb collisions at 2.76 TeV, related to initial-state fluctuations, are analyzed and interpreted within the HYDJET＋＋ model. Using the newly introduced Principal Component Analysis（PCA） method applied to two-particle azimuthal correlations extracted from the model calculations, the leading and sub-leading flow modes are studied as a function of the transverse momentum（p T） over a wide centrality range. The leading modes of the elliptic（v2^（1）） and triangular（v3^（1）） flow calculated with the HYDJET＋＋ model reproduce rather well the v2 {2} and v3 {2} coefficients measured experimentally using the two-particle correlations. Within the p T 3 Ge V/c range, where hydrodynamics dominates, the sub-leading flow effects are greatest at the highest p T of around 3 Ge V/c. The sub-leading elliptic flow mode（v2^（2））, which corresponds to the n = 2 harmonic, has a small non-zero value and slowly increases from central to peripheral collisions, while the sub-leading triangular flow mode（v3^（2））, which corresponds to the n = 3 harmonic, is even smaller and does not depend on centrality. For n= 2, the relative magnitude of the effect measured with respect to the leading flow mode shows a shallow minimum for semi-central collisions and increases for very central and for peripheral collisions. For the n= 3 case, there is no centrality dependence. The sub-leading flow mode results obtained from the HYDJET＋＋model are in rather good agreement with the experimental measurements of the CMS Collaboration.展开更多
基金supported by the Doctoral Scientific Research Foundation of Pingdingshan University(PXY-BSQD-2023016)the Natural Science Foundation of Henan(252300420921)+1 种基金the National Key Research and Development Program of China(2022YFA1604900)the National Natural Science Foundation of China(NSFC)(12175084)。
文摘We present a systematic study of the elliptic flow v_(2) relative to the participant plane(PP)and reaction plane(RP)in Au+Au collisions at√SNN=7.7-200 Ge V using the AMPT model(string melting version).The ratio v_(2)^(PP)/v_(2)^(RP)is investigated under different hadronic cascade times(0.6 fm/c,10 fm/c,and the maximum evolution time)and across various collision centralities.The results show that,at a fixed collision energy,the ratio exhibits negligible sensitivity to the duration of the hadronic rescattering stage,indicating that hadronic interactions have a minimal effect on the relative difference generated by initial-state fluctuations.However,a strong energy dependence is observed:the ratio increases with beam energy and saturates above√SNN≈62.4GeV,a trend that persists across all centralities.These findings highlight the dominant role of the partonic phase in converting initial-state geometry fluctuations into final-state momentum anisotropy.Conversely,at lower energies,the reduced partonic interaction strength limits the efficiency of this conversion,weakening the system’s ability to preserve the initial geometric information.Our results suggest that the conversion of initial geometric fluctuations into final momentum anisotropy requires sufficient partonic interactions.
基金Supported by National Natural Science Foundation of China(11275211)Istituto Nazionale di Fisica Nucleare,Italy
文摘A detailed theoretical derivation of the cross sections of e^＋e^-→e^＋e^-and e^＋e^-→μ＋μ-around the J/ψ resonance is reported. The resonance and interference parts of the cross sections, related to J/ψ resonance parameters, are calculated. Higher-order corrections for vacuum polarization and initial-state radiation are considered. An arbitrary upper limit of radiative correction integration is involved. Full and simplified versions of analytic formulae are given with precision at the level of 0.1% and 0.2%, respectively. Moreover, the results obtained in the paper can be applied to the case of the ψ（3686） resonance.
基金Supported by Ministry of Education,Science and Technological Development of the Republic of Serbia(171019)
文摘Recent LHC results on the appearance of sub-leading flow modes in Pb Pb collisions at 2.76 TeV, related to initial-state fluctuations, are analyzed and interpreted within the HYDJET＋＋ model. Using the newly introduced Principal Component Analysis（PCA） method applied to two-particle azimuthal correlations extracted from the model calculations, the leading and sub-leading flow modes are studied as a function of the transverse momentum（p T） over a wide centrality range. The leading modes of the elliptic（v2^（1）） and triangular（v3^（1）） flow calculated with the HYDJET＋＋ model reproduce rather well the v2 {2} and v3 {2} coefficients measured experimentally using the two-particle correlations. Within the p T 3 Ge V/c range, where hydrodynamics dominates, the sub-leading flow effects are greatest at the highest p T of around 3 Ge V/c. The sub-leading elliptic flow mode（v2^（2））, which corresponds to the n = 2 harmonic, has a small non-zero value and slowly increases from central to peripheral collisions, while the sub-leading triangular flow mode（v3^（2））, which corresponds to the n = 3 harmonic, is even smaller and does not depend on centrality. For n= 2, the relative magnitude of the effect measured with respect to the leading flow mode shows a shallow minimum for semi-central collisions and increases for very central and for peripheral collisions. For the n= 3 case, there is no centrality dependence. The sub-leading flow mode results obtained from the HYDJET＋＋model are in rather good agreement with the experimental measurements of the CMS Collaboration.
