The solutions of the relativistic viscous hydrodynamics for longitudinally expanding fireballs are investig-ated with the Navier-Stokes theory and Israel-Stewart theory.The energy and the Euler conservation equations ...The solutions of the relativistic viscous hydrodynamics for longitudinally expanding fireballs are investig-ated with the Navier-Stokes theory and Israel-Stewart theory.The energy and the Euler conservation equations for the viscous fluid are derived in Rindler coordinates,by assuming that the longitudinal expansion effect is small.Under the perturbation assumption,an analytical perturbation solution for the Navier-Stokes approximation and numerical solutions for the Israel-Stewart approximation are presented.The temperature evolution with both shear viscous ef-fect and longitudinal acceleration effect in the longitudinal expanding framework are presented.The specific temper-ature profile shows symmetric Gaussian shape in the Rindler coordinates.Further,we compare the results from the Israel-Stewart approximation with the results from the Bjorken and the Navier-Stokes approximations,in the pres-ence of the longitudinal acceleration expansion effect.We found that the Israel-Stewart approximation gives a good description of the early stage evolutions than the Navier-Stokes theory.展开更多
We report results of a comprehensive global х~2 analysis of nuclear collision data from RHIC(0.2 ATeV),LHC1(2.76 ATeV), and recent LHC2(5.02 ATeV) energies using the updated CUJET framework. The framework consistentl...We report results of a comprehensive global х~2 analysis of nuclear collision data from RHIC(0.2 ATeV),LHC1(2.76 ATeV), and recent LHC2(5.02 ATeV) energies using the updated CUJET framework. The framework consistently combines viscous hydrodynamic fields predicted by VISHNU2+1(validated with soft p_T﹤2 GeV bulk observables) and the DGLV theory of jet elastic and inelastic energy loss generalized to QGP fluids with an sQGMP color structure, including effective semi-QGP color electric quark and gluon as well as emergent color magnetic monopole degrees of freedom constrained by lattice QCD data. We vary the two control parameters of the model(the maximum value of the running QCD coupling, c, and the ratio cm of color magnetic to electric screening scales) and calculate the global х~2(α_c,c_m) compared with available jet fragment observables( R_(AA),v_2). A global х~2 minimum is found with α_c≈0.9±0.1 and c_m≈0.25±0.03. Using CIBJET, the event-by-event(ebe) generalization of the CUJET framework, we show that ebe fluctuations in the initial conditions do not significantly alter our conclusions(except for v_3). An important theoretical advantage of the CUJET and CIBJET frameworks is not only its global х~2 consistency with jet fragment observables at RHIC and LHC and with non-perturbative lattice QCD data, but also its internal consistency of the constrained jet transport coefficient, ■(E,T)/T^3, with the near-perfect fluid viscosity to entropy ratio(η/s~T^3/■~0.1-0.2) property of QCD fluids near Tc needed to account for the low p_T﹤2 GeV flow observables. Predictions for future tests at LHC with 5.44 ATeV Xe + Xe and 5.02 ATeV Pb + Pb are also presented.展开更多
We investigate mesonic condensation in isospin matter under rotation.Using the two-flavor NJL effective model in the presence of global rotation,we demonstrate two important effects of rotation on its phase structure:...We investigate mesonic condensation in isospin matter under rotation.Using the two-flavor NJL effective model in the presence of global rotation,we demonstrate two important effects of rotation on its phase structure:a rotational suppression of the scalar-channel condensates,in particular,the pion condensation region;and a rotational enhancement of the rho condensation region with vector-channel condensate.A new phase diagram for isospin matter under rotation is mapped out on the ω−μI plane where the three distinct phases,corresponding to the σ,π,ρ-dominated regions,respectively,are separated by a second-order line at low isospin chemical potential as well as a first-order line at high rotation and are further connected at a tri-critical point.展开更多
We present a high precision frequency determination method for digitized NMR FID signals.The method employs high precision numerical integration rather than simple summation as in many other techniques.With no indepen...We present a high precision frequency determination method for digitized NMR FID signals.The method employs high precision numerical integration rather than simple summation as in many other techniques.With no independent knowledge of the other parameters of a NMR FID signal(phaseφ,amplitude A,and transverse relaxation time T_(2))this method can determine the signal frequency f_(0)with a precision of 1/(8π^(2)f_(0)^(2)T_(2)^(2))if the observation time T≫T_(2).The method is especially convenient when the detailed shape of the observed FT NMR spectrum is not well defined.When T2 is+∞and the signal becomes pure sinusoidal,the precision of the method is 3/(2π^(2)f_(0)^(2)T_(2))which is one order more precise than the±1 count error induced precision of a typical frequency counter.Analysis of this method shows that the integration reduces the noise by bandwidth narrowing as in a lock-in amplifier,and no extra signal filters are needed.For a pure sinusoidal signal we find from numerical simulations that the noise-induced error in this method reaches the Cramer-Rao Lower Band(CRLB)on frequency determination.For the damped sinusoidal case of most interest,the noise-induced error is found to be within a factor of 2 of CRLB when the measurement time T is 2 or 3 times larger than T2.We discuss possible improvements for the precision of this method.展开更多
We develop a comprehensive dynamical framework, CIBJET, to calculate on an event-by-event basis the dependence of correlations between soft (PT 〈2 GeV) and hard (PT 〉 10 GeV) azimuthal flow angle harmonics on th...We develop a comprehensive dynamical framework, CIBJET, to calculate on an event-by-event basis the dependence of correlations between soft (PT 〈2 GeV) and hard (PT 〉 10 GeV) azimuthal flow angle harmonics on the color composition of near-perfect QCD fluids produced in high energy nuclear collisions at RHIC and LHC. CIBJET combines consistently predictions of event-by-event VISHNU2+I viscous hydrodynamic fluid fields with CUJET3.1 predictions of event-by-event jet quenching. We find that recent correlation data favor a temperature dependent color composition including bleached chromo-electric q(T)+g(T) components and an emergent chromo-magnetic degrees of freedom re(T) consistent with non-perturbative lattice QCD information in the confinement/deconfinement temperature range.展开更多
The last few years have been witness to a proliferation of new results concerning heavy exotic hadrons.Experimentally, many new signals have been discovered that could be pointing towards the existence of tetraquarks,...The last few years have been witness to a proliferation of new results concerning heavy exotic hadrons.Experimentally, many new signals have been discovered that could be pointing towards the existence of tetraquarks,pentaquarks, and other exotic configurations of quarks and gluons. Theoretically, advances in lattice field theory techniques place us at the cusp of understanding complex coupled-channel phenomena, modelling grows more sophisticated, and effective field theories are being applied to an ever greater range of situations. It is thus an opportune time to evaluate the status of the field. In the following, a series of high priority experimental and theoretical issues concerning heavy exotic hadrons is presented.展开更多
We studied the chiral magnetic effect in AuAu,RuRu,and ZrZr collisions at sNN−√=200GeV.The axial charge evolution was modeled with stochastic hydrodynamics,and geometrical quantities were calculated with the Monte Ca...We studied the chiral magnetic effect in AuAu,RuRu,and ZrZr collisions at sNN−√=200GeV.The axial charge evolution was modeled with stochastic hydrodynamics,and geometrical quantities were calculated with the Monte Carlo Glauber model.By adjusting the relaxation time of the magnetic field,we found our results are in good agreement with background subtracted data for AuAu collisions at the same energy.We also made predictions for RuRu and ZrZr collisions.We found a weak centrality dependence on initial chiral imbalance,which implies that the centrality dependence of chiral magnetic effect signals results mainly from the effects of the magnetic field and volume factor.Furthermore,our results show an unexpected dependence on system size.While the AuAu system has larger chiral imbalance and magnetic field,it was observed to have a smaller signal for the chiral magnetic effect due to the larger volume suppression factor.展开更多
Hydrodynamics is a general theoretical framework for describing the long-time large-distance behaviors of macroscopic physical systems.It has many important applications in various branches of physics,from cosmic expa...Hydrodynamics is a general theoretical framework for describing the long-time large-distance behaviors of macroscopic physical systems.It has many important applications in various branches of physics,from cosmic expansion and galaxy/star evolutions at the very large scales to relativistic nuclear collisions at the very small scales.The core of hydrodynamics is about physical quantities protected by exact conservation laws,such as energy,momentum and conserved charges.Past hydrodynamic studies almost entirely focus on the energy–momentum conservation and charge conservation.Only very recently,there has been a rapidly increasing interest in understanding the role of angular momentum conservation in the hydrodynamic context and its implications for spin transport of underlying constituents.展开更多
The Chiral Magnetic Effect(CME) is a macroscopic manifestation of fundamental chiral anomaly in a many-body system of chiral fermions, and emerges as an anomalous transport current in the fluid dynamics framework. E...The Chiral Magnetic Effect(CME) is a macroscopic manifestation of fundamental chiral anomaly in a many-body system of chiral fermions, and emerges as an anomalous transport current in the fluid dynamics framework. Experimental observation of the CME is of great interest and has been reported in Dirac and Weyl semimetals. Significant efforts have also been made to look for the CME in heavy ion collisions. Critically needed for such a search is the theoretical prediction for the CME signal. In this paper we report a first quantitative modeling framework, Anomalous Viscous Fluid Dynamics(AVFD), which computes the evolution of fermion currents on top of realistic bulk evolution in heavy ion collisions and simultaneously accounts for both anomalous and normal viscous transport effects. AVFD allows a quantitative understanding of the generation and evolution of CME-induced charge separation during the hydrodynamic stage, as well as its dependence on theoretical ingredients. With reasonable estimates of key parameters, the AVFD simulations provide the first phenomenologically successful explanation of the measured signal in 200 AGe V Au Au collisions.展开更多
基金Supported by the Ministry of Science and Technology of China(MSTC)under the"973"Project No.2015CB856904(4),NSFC(11735007,11890711)the Sino-Hungarian bilateral Cooperation Program(Te'T 12CN-1-2012-0016)D.She is Supported by the China Scholarship Council(CSC)(201906770027)。
文摘The solutions of the relativistic viscous hydrodynamics for longitudinally expanding fireballs are investig-ated with the Navier-Stokes theory and Israel-Stewart theory.The energy and the Euler conservation equations for the viscous fluid are derived in Rindler coordinates,by assuming that the longitudinal expansion effect is small.Under the perturbation assumption,an analytical perturbation solution for the Navier-Stokes approximation and numerical solutions for the Israel-Stewart approximation are presented.The temperature evolution with both shear viscous ef-fect and longitudinal acceleration effect in the longitudinal expanding framework are presented.The specific temper-ature profile shows symmetric Gaussian shape in the Rindler coordinates.Further,we compare the results from the Israel-Stewart approximation with the results from the Bjorken and the Navier-Stokes approximations,in the pres-ence of the longitudinal acceleration expansion effect.We found that the Israel-Stewart approximation gives a good description of the early stage evolutions than the Navier-Stokes theory.
基金Supported by the National Science Foundation(PHY-1352368)IOPP of CCNU Wuhan China,the computations in this study were performed on IU's Big Red Ⅱ clusters,supported in part by the Lilly Endowment,Inc.+1 种基金support for the Indiana University Pervasive Technology Institute,and in part by the Indiana METACyt InitiativeThe Indiana METACyt Initiative at IU was also supported in part by the Lilly Endowment,Inc.
文摘We report results of a comprehensive global х~2 analysis of nuclear collision data from RHIC(0.2 ATeV),LHC1(2.76 ATeV), and recent LHC2(5.02 ATeV) energies using the updated CUJET framework. The framework consistently combines viscous hydrodynamic fields predicted by VISHNU2+1(validated with soft p_T﹤2 GeV bulk observables) and the DGLV theory of jet elastic and inelastic energy loss generalized to QGP fluids with an sQGMP color structure, including effective semi-QGP color electric quark and gluon as well as emergent color magnetic monopole degrees of freedom constrained by lattice QCD data. We vary the two control parameters of the model(the maximum value of the running QCD coupling, c, and the ratio cm of color magnetic to electric screening scales) and calculate the global х~2(α_c,c_m) compared with available jet fragment observables( R_(AA),v_2). A global х~2 minimum is found with α_c≈0.9±0.1 and c_m≈0.25±0.03. Using CIBJET, the event-by-event(ebe) generalization of the CUJET framework, we show that ebe fluctuations in the initial conditions do not significantly alter our conclusions(except for v_3). An important theoretical advantage of the CUJET and CIBJET frameworks is not only its global х~2 consistency with jet fragment observables at RHIC and LHC and with non-perturbative lattice QCD data, but also its internal consistency of the constrained jet transport coefficient, ■(E,T)/T^3, with the near-perfect fluid viscosity to entropy ratio(η/s~T^3/■~0.1-0.2) property of QCD fluids near Tc needed to account for the low p_T﹤2 GeV flow observables. Predictions for future tests at LHC with 5.44 ATeV Xe + Xe and 5.02 ATeV Pb + Pb are also presented.
基金supported by the Ministry of Science and Technology of China (MSTC) under the"973"(2015CB856904(4))by NSFC (11735007)+3 种基金by NSF (PHY-1352368,PHY-1913729)by the U.S. Department of Energy,Office of Science,Office of Nuclear Physics,within the framework of the Beam Energy Scan Theory (BEST)Topical Collaborationpartial support from the China Scholarship Councilthe Institute for Advanced Study of Indiana University for partial support.
文摘We investigate mesonic condensation in isospin matter under rotation.Using the two-flavor NJL effective model in the presence of global rotation,we demonstrate two important effects of rotation on its phase structure:a rotational suppression of the scalar-channel condensates,in particular,the pion condensation region;and a rotational enhancement of the rho condensation region with vector-channel condensate.A new phase diagram for isospin matter under rotation is mapped out on the ω−μI plane where the three distinct phases,corresponding to the σ,π,ρ-dominated regions,respectively,are separated by a second-order line at low isospin chemical potential as well as a first-order line at high rotation and are further connected at a tri-critical point.
基金supported by the Department of Energy and by NSF grant PHY-1068712.support from the Indiana University Center for Spacetime Symmetries and the Indiana University Collaborative Research Grant program+1 种基金supported by NSF grant PHY-1207656.support.C.Fu acknowledges the support from the Specialized Research Fund for the Doctoral Program of Higher Education under grant 20120073110065.
文摘We present a high precision frequency determination method for digitized NMR FID signals.The method employs high precision numerical integration rather than simple summation as in many other techniques.With no independent knowledge of the other parameters of a NMR FID signal(phaseφ,amplitude A,and transverse relaxation time T_(2))this method can determine the signal frequency f_(0)with a precision of 1/(8π^(2)f_(0)^(2)T_(2)^(2))if the observation time T≫T_(2).The method is especially convenient when the detailed shape of the observed FT NMR spectrum is not well defined.When T2 is+∞and the signal becomes pure sinusoidal,the precision of the method is 3/(2π^(2)f_(0)^(2)T_(2))which is one order more precise than the±1 count error induced precision of a typical frequency counter.Analysis of this method shows that the integration reduces the noise by bandwidth narrowing as in a lock-in amplifier,and no extra signal filters are needed.For a pure sinusoidal signal we find from numerical simulations that the noise-induced error in this method reaches the Cramer-Rao Lower Band(CRLB)on frequency determination.For the damped sinusoidal case of most interest,the noise-induced error is found to be within a factor of 2 of CRLB when the measurement time T is 2 or 3 times larger than T2.We discuss possible improvements for the precision of this method.
基金Supported by National Science Foundation(PHY-1352368)
文摘We develop a comprehensive dynamical framework, CIBJET, to calculate on an event-by-event basis the dependence of correlations between soft (PT 〈2 GeV) and hard (PT 〉 10 GeV) azimuthal flow angle harmonics on the color composition of near-perfect QCD fluids produced in high energy nuclear collisions at RHIC and LHC. CIBJET combines consistently predictions of event-by-event VISHNU2+I viscous hydrodynamic fluid fields with CUJET3.1 predictions of event-by-event jet quenching. We find that recent correlation data favor a temperature dependent color composition including bleached chromo-electric q(T)+g(T) components and an emergent chromo-magnetic degrees of freedom re(T) consistent with non-perturbative lattice QCD information in the confinement/deconfinement temperature range.
基金Supported by U.S.Department of Energythe Institute of Modern Physics and Chinese Academy of Sciences under contract Y104160YQ0 and agreement No.2015-BH-02+16 种基金the U.S.Department of Energy,for grant DE-AC05-06OR23177,under which Jefferson Science Associates,LLC,manages and operates Jefferson Laboratory and DE-SC0006765,Early Career awardFermilab,operated by the Fermi Research Alliance under contract number DEAC02-07CH11359 with the U.S.Department of EnergyBMBF,under contract No.06GI7121,and the DAAD under contract No.56889822 and by the Helmholtz International Center for FAIR within the LOEWE program of the State of Hessethe German Research Foundation DFG under contract number Collaborative Research Centre CRC-1044the Conselho Nacional de Desenvolvimento Científico e Tecnolgico-CNPq,Grant No.305894/2009-9Fundao de Amparoà Pesquisa do Estado de So Paulo-FAPESP,Grant No.2013/01907-0U.S.National Science Foundation,under grants PHY-1068286 and PHY-1403891the Brazilian National Council for Scientific and Technological Development under grant CNPq/CAPES-208188/2014-2U.S.Department of Energy under grant DE-FG02-05ER41374U.S.National Science Foundation under grant PHY-1306805U.S.Department of Energy,supported by Jefferson Science Associates,LLC under contract No.DE-AC05-06OR23177the National Natural Science Foundation of China(NSFC)under contract No.11575017the Ministry of Science and Technology of China under Contract No.2015CB856701U.S.Department of Energy,under grant DE-FG02-05ER41374U.S.National Science Foundation under grant PHY-1507572U.S.Department of Energy,under contract DE-AC05-06OR23177 and grant DE-FG0287ER40365the National Natural Science Foundation of China(NSFC)under contract numbers 11235011 and 11475187
文摘The last few years have been witness to a proliferation of new results concerning heavy exotic hadrons.Experimentally, many new signals have been discovered that could be pointing towards the existence of tetraquarks,pentaquarks, and other exotic configurations of quarks and gluons. Theoretically, advances in lattice field theory techniques place us at the cusp of understanding complex coupled-channel phenomena, modelling grows more sophisticated, and effective field theories are being applied to an ever greater range of situations. It is thus an opportune time to evaluate the status of the field. In the following, a series of high priority experimental and theoretical issues concerning heavy exotic hadrons is presented.
基金supported by the National Natural Science Foundation of China(12035007,12022512,12147131,12225503,11890710,11890711,and 11935007)Guangdong Major Project of Basic and Applied Basic Research(2020B0301030008)+1 种基金supported by the MOE Key Laboratory of Quark and Lepton Physics(QLPL2021P01)supported by the National Science Foundation of USA(PHY-2209183).
基金Supported by International Program for Ph.D Candidates,Sun Yat-Sen University,the National Science Foundation(PHY-1913729)the National Natural Science Foundation of China(11675274,11735007)the Shang-hai Pujiang Program(19PJ1401400)。
文摘We studied the chiral magnetic effect in AuAu,RuRu,and ZrZr collisions at sNN−√=200GeV.The axial charge evolution was modeled with stochastic hydrodynamics,and geometrical quantities were calculated with the Monte Carlo Glauber model.By adjusting the relaxation time of the magnetic field,we found our results are in good agreement with background subtracted data for AuAu collisions at the same energy.We also made predictions for RuRu and ZrZr collisions.We found a weak centrality dependence on initial chiral imbalance,which implies that the centrality dependence of chiral magnetic effect signals results mainly from the effects of the magnetic field and volume factor.Furthermore,our results show an unexpected dependence on system size.While the AuAu system has larger chiral imbalance and magnetic field,it was observed to have a smaller signal for the chiral magnetic effect due to the larger volume suppression factor.
基金supported in part by the National Natural Science Foundation of China (11735007, 11890711, 11890710, 12275104, and 12205309)the China Scholarship Council (201906770027)+2 种基金the Fundamental Research Funds for the Central Universitiesby the NSF (PHY-2209183)the U.S. Department of Energy, Office of Science, Office of Nuclear Physics,within the framework of the Beam Energy Scan Theory (BEST) Topical Collaboration
文摘Hydrodynamics is a general theoretical framework for describing the long-time large-distance behaviors of macroscopic physical systems.It has many important applications in various branches of physics,from cosmic expansion and galaxy/star evolutions at the very large scales to relativistic nuclear collisions at the very small scales.The core of hydrodynamics is about physical quantities protected by exact conservation laws,such as energy,momentum and conserved charges.Past hydrodynamic studies almost entirely focus on the energy–momentum conservation and charge conservation.Only very recently,there has been a rapidly increasing interest in understanding the role of angular momentum conservation in the hydrodynamic context and its implications for spin transport of underlying constituents.
基金supported by the U.S.Department of Energy,Office of Science,Office of Nuclear Physics,within the framework of the Beam Energy Scan Theory(BEST)Topical Collaborationsupported in part by the National Science Foundation under Grant No.PHY-1352368(SS and JL)+4 种基金by the National Science Foundation of China under Grant No.11735007(JL)by the U.S.Department of Energy under grant Contract Number No.DE-SC0012704(BNL)/DE-SC0011090(MIT)(YY)the Institute for Nuclear Theory for hospitality during the INT-16-3 Programperformed on IU’s Big Red Ⅱ cluster,supported in part by Lilly Endowment,Inc.(through its support for the Indiana University Pervasive Technology Institute)in part by the Indiana METACyt Initiative
文摘The Chiral Magnetic Effect(CME) is a macroscopic manifestation of fundamental chiral anomaly in a many-body system of chiral fermions, and emerges as an anomalous transport current in the fluid dynamics framework. Experimental observation of the CME is of great interest and has been reported in Dirac and Weyl semimetals. Significant efforts have also been made to look for the CME in heavy ion collisions. Critically needed for such a search is the theoretical prediction for the CME signal. In this paper we report a first quantitative modeling framework, Anomalous Viscous Fluid Dynamics(AVFD), which computes the evolution of fermion currents on top of realistic bulk evolution in heavy ion collisions and simultaneously accounts for both anomalous and normal viscous transport effects. AVFD allows a quantitative understanding of the generation and evolution of CME-induced charge separation during the hydrodynamic stage, as well as its dependence on theoretical ingredients. With reasonable estimates of key parameters, the AVFD simulations provide the first phenomenologically successful explanation of the measured signal in 200 AGe V Au Au collisions.