Following over 20 years of research,a direct measurement of the QGP temperature has been achieved at Relativistic Heavy-Ion Collider(RHIC),free from the blue-shift effect and contamination from strong interactions.Thi...Following over 20 years of research,a direct measurement of the QGP temperature has been achieved at Relativistic Heavy-Ion Collider(RHIC),free from the blue-shift effect and contamination from strong interactions.This viewpoint discusses a recent measurement of the QGP temperature at different stages at the Solenoidal Tracker at RHIC(STAR),which used e^(+)e^(-)pairs as penetrating probes.展开更多
The spontaneous conversion of muonium to antimuonium is an interesting charged lepton flavor violation phenomenon that offers a sensitive probe for potential new physics and serves as a tool to constrain the parameter...The spontaneous conversion of muonium to antimuonium is an interesting charged lepton flavor violation phenomenon that offers a sensitive probe for potential new physics and serves as a tool to constrain the parameter space beyond the Standard Model.The Muonium-to-Antimuonium Conversion Experiment(MACE)was designed to utilize a high-intensity muon beam,a Michel electron magnetic spectrometer,a positron transport system,and a positron detection system to either discover or constrain this rare process with a conversion probability of O(10^(-13)).This article presents an overview of the theoretical framework and a detailed description of the experimental design for muonium-to-antimuonium conversion.展开更多
Leveraging high-precision lattice QCD data on the equation of state and baryon number susceptibility at a vanishing chemical potential,we constructed a Bayesian holographic QCD model and systematically analyzed the th...Leveraging high-precision lattice QCD data on the equation of state and baryon number susceptibility at a vanishing chemical potential,we constructed a Bayesian holographic QCD model and systematically analyzed the thermodynamic properties of heavy quarkonium in QCD matter under varying temperatures and chemical potentials.We computed the quark-antiquark interquark distance,potential energy,entropy,binding energy,and internal energy.We present detailed posterior distribution results of the thermodynamic quantities of heavy quarkonium,including maximum a posteriori(MAP)value estimates and 95%confidence levels(CL).Through numerical simulations and theoretical analysis,we find that an increase in the temperature and chemical potential reduces the quark distance,thereby facilitating the dissociation of heavy quarkonium and leading to a suppressed potential energy.The increase in temperature and chemical potential also raises the entropy and entropy force,further accelerating the dissociation of heavy quarkonium.The calculated results of binding energy indicate that a higher temperature and chemical potential enhance the tendency of heavy quarkonium to dissociate into free quarks.The internal energy also increases with rising temperature and chemical potential.These findings provide significant theoretical insights into the properties of strongly interacting matter under extreme conditions and lay a solid foundation for the interpretation and validation of future experimental data.Finally,we also present the results for the free energy,entropy,and internal energy of a single quark.展开更多
A coalescence model was employed to form deuterons(d),tritons(t),and helium-3(^(3)He)nuclei from a uniformly-distributed volume of protons(p)and neutrons(n).We studied the ratio N_(t)N_(p)/N_(d)^(2)of light nuclei yie...A coalescence model was employed to form deuterons(d),tritons(t),and helium-3(^(3)He)nuclei from a uniformly-distributed volume of protons(p)and neutrons(n).We studied the ratio N_(t)N_(p)/N_(d)^(2)of light nuclei yields as a function of the neutron density fluctuations.We investigated the effect of finite transverse momentum(p_(T))acceptance on the ratio,in particular,the“extrapolation factor”(f)for the ratio as a function of the p_(T)spectral shape and the magnitude of neutron density fluctuations.The nature of f was found to be monotonic in p_(T)spectra“temperature”parameter and neutron density fluctuation magnitude;variations in the latter are relatively small.We also examined f in realistic simulations using the kinematic distributions of protons measured from the heavy-ion collision data.The nature of f was found to be smooth and monotonic as a function of the beam energy.Therefore,we conclude that extrapolation from limited p_(T)ranges does not create,enhance,or reduce the local peak of the N_(t)N_(p)/N_(d)^(2)ratio in the beam energy.Our study provides a necessary benchmark for light nuclei ratios as a probe for nucleon density fluctuations,an important observation in the search for the critical point of nuclear matter.展开更多
文摘Following over 20 years of research,a direct measurement of the QGP temperature has been achieved at Relativistic Heavy-Ion Collider(RHIC),free from the blue-shift effect and contamination from strong interactions.This viewpoint discusses a recent measurement of the QGP temperature at different stages at the Solenoidal Tracker at RHIC(STAR),which used e^(+)e^(-)pairs as penetrating probes.
基金supported by National Natural Science Foundation of China(Nos.12075326,11535014,11975017,12475191,11905092,12105132 and 12175039)Guangdong Basic and Applied Basic Research Foundation(No.2025A1515010669)+7 种基金Natural Science Foundation of Guangzhou(No.2024A04J6243)Fundamental Research Funds for the Central Universities(23xkjc017)in Sun Yat-sen UniversityBasic Research Conditions and Major Scientific Instrument and Equipment Research and Development Projects of the Ministry of Science and Technology(No.2022YFF0705602)the State Key Laboratory of Particle Detection and Electronics(SKLPDE-ZZ-202412)Natural Science Foundation of Shandong Province(No.2023HWYQ-010)the“Fundamental Research Funds for the Central Universities”at Southeast Universitythe National Development and Reform Commission of China(Large Research Infrastructures of 12th Five-Year Plan:China initiative Accelerator Driven System)(No.2017-000052-75-01-000590)Innovation Training Program for bachelor students in Sun Yat-sen University。
文摘The spontaneous conversion of muonium to antimuonium is an interesting charged lepton flavor violation phenomenon that offers a sensitive probe for potential new physics and serves as a tool to constrain the parameter space beyond the Standard Model.The Muonium-to-Antimuonium Conversion Experiment(MACE)was designed to utilize a high-intensity muon beam,a Michel electron magnetic spectrometer,a positron transport system,and a positron detection system to either discover or constrain this rare process with a conversion probability of O(10^(-13)).This article presents an overview of the theoretical framework and a detailed description of the experimental design for muonium-to-antimuonium conversion.
基金supported in part by the National Key Research and Development Program of China(No.2022YFA1604900)the National Natural Science Foundation of China(NSFC)(Nos.12405154,12235016,12221005,12435009,12275104,92570117)+7 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB34030000)the Fundamental Research Funds for the Central UniversitiesOpen fund for Key Laboratories of the Ministry of Education(No.QLPL2024P01)CUHK-Shenzhen University Development Fund(Nos.UDF01003041 and UDF03003041)Shenzhen Peacock Fund(No.2023TC0007)Ministry of Science and Technology of China(No.2024YFA1611004)the European Union–Next Generation EU through the research(No.P2022Z4P4B)“SOPHYA-Sustainable Optimized PHYsics Algorithms:fundamental physics to build an advanced society”under the program PRIN 2022 PNRR of the Italian Ministero dell’Universitàe Ricerca(MUR)。
文摘Leveraging high-precision lattice QCD data on the equation of state and baryon number susceptibility at a vanishing chemical potential,we constructed a Bayesian holographic QCD model and systematically analyzed the thermodynamic properties of heavy quarkonium in QCD matter under varying temperatures and chemical potentials.We computed the quark-antiquark interquark distance,potential energy,entropy,binding energy,and internal energy.We present detailed posterior distribution results of the thermodynamic quantities of heavy quarkonium,including maximum a posteriori(MAP)value estimates and 95%confidence levels(CL).Through numerical simulations and theoretical analysis,we find that an increase in the temperature and chemical potential reduces the quark distance,thereby facilitating the dissociation of heavy quarkonium and leading to a suppressed potential energy.The increase in temperature and chemical potential also raises the entropy and entropy force,further accelerating the dissociation of heavy quarkonium.The calculated results of binding energy indicate that a higher temperature and chemical potential enhance the tendency of heavy quarkonium to dissociate into free quarks.The internal energy also increases with rising temperature and chemical potential.These findings provide significant theoretical insights into the properties of strongly interacting matter under extreme conditions and lay a solid foundation for the interpretation and validation of future experimental data.Finally,we also present the results for the free energy,entropy,and internal energy of a single quark.
基金supported in part by the U.S.Department of Energy(No.DE-SC0012910)National Nature Science Foundation of China(Nos.12035006 and 12075085)the Ministry of Science and Technology of China(No.2020YFE020200)。
文摘A coalescence model was employed to form deuterons(d),tritons(t),and helium-3(^(3)He)nuclei from a uniformly-distributed volume of protons(p)and neutrons(n).We studied the ratio N_(t)N_(p)/N_(d)^(2)of light nuclei yields as a function of the neutron density fluctuations.We investigated the effect of finite transverse momentum(p_(T))acceptance on the ratio,in particular,the“extrapolation factor”(f)for the ratio as a function of the p_(T)spectral shape and the magnitude of neutron density fluctuations.The nature of f was found to be monotonic in p_(T)spectra“temperature”parameter and neutron density fluctuation magnitude;variations in the latter are relatively small.We also examined f in realistic simulations using the kinematic distributions of protons measured from the heavy-ion collision data.The nature of f was found to be smooth and monotonic as a function of the beam energy.Therefore,we conclude that extrapolation from limited p_(T)ranges does not create,enhance,or reduce the local peak of the N_(t)N_(p)/N_(d)^(2)ratio in the beam energy.Our study provides a necessary benchmark for light nuclei ratios as a probe for nucleon density fluctuations,an important observation in the search for the critical point of nuclear matter.
