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Electromagnetic fields in ultra-peripheral relativistic heavy-ion collisions

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nuclear Science and Techniques 2024年第2期35卷 103-109页

作者： Jie Zhao Jin-Hui Chen Xu-Guang Huang Yu-Gang Ma Key Laboratory of nuclear physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China Shanghai Research center for theoretical {2. physics NSFC and Fudan UniversityShanghai 200438China physics Department and center for Particle physics and Field Theory Fudan UniversityShanghai 200438China

Ultra-peripheral heavy-ion collisions(UPCs)offer unique opportunities to study processes under strong electromagnetic *** these collisions,highly charged fast-moving ions carry strong electromagnetic fields that can be effectively treated as photon *** exchange of photons can induce photonuclear and two-photon interactions and excite *** excitation of the ions results in Coulomb dissociation with the emission of photons,neutrons,and other ***,the electromagnetic fields generated by the ions can be sufficiently strong to enforce mutual interactions between the two colliding ***,the two colliding ions experience an electromagnetic force that pushes them in opposite directions,causing a back-to-back correlation in the emitted *** a Monte Carlo simulation,we qualitatively demonstrate that the above electromagnetic effect is large enough to be observed in UPCs,which would provide a clear means to study strong electromagnetic fields and their effects.

关键词： Electromagnetic fields Neutrons Ultra-peripheral relativistic heavy-ion collisions(UPC)

Observational appearances of hairy black holes in the framework of gravitational decoupling

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Communications in theoretical physics 2024年第8期76卷 103-117页

作者： Yizhi Liang Xin Lyu Jun Tao center for theoretical {2. College of PhysicsSichuan UniversityChengdu 610065China

We investigate the observational appearance of static and spherically symmetric hairy black holes in the framework of gravitational decoupling with the weak energy condition(WEC). Two types of thin illumination conditions are studied: spherical accretion and disk accretion. As the hairy parameter increases, the size of the photon sphere and photon rings in both models decreases, and the overall luminosity attenuation becomes more pronounced. In spherical accretion, the luminosity of infalling accretion is significantly lower than that of stationary accretion. In disk accretion the luminosity of the black hole is contributed by direct emission, the lensing ring and the photon ring. Employing four types of astrophysical disk luminosity model,we investigate the appearance of halos and note that their luminosities do not superimpose when the source is on or beyond the innermost stable circular orbit.

关键词： hairy black hole shadow gravitational decoupling accretion disk

Distinguishing the observational signatures of hot spots orbiting Reissner-Nordström spacetime

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Chinese physics C 2024年第7期48卷 221-230页

作者：吴天枢陈一千 center for theoretical {2. College of PhysicsSichuan UniversityChengdu 610064China

This paper investigates observable signatures of hot spots orbiting Reissner-Nordström(RN)black holes and naked *** an RN black hole,we find two discernible lensing image tracks in time integrated images,capturing a complete orbit of hot spots and a image shadow within the critical curve where photons with a small impact parameter fall into the event ***,in RN singularities,additional image tracks can be found within the critical curve,originating from photons reflected by the infinitely high effective potential ***,we find incomplete and converging tracks from the time integrated images of hot spot orbiting RN singularities that have no photon *** presence of these additional image tracks significantly influences temporal magnitudes at their local maxima,enabling us to differentiate between RN black holes and RN naked singularities.

关键词： astrometry gravitational lensing black hole physics D0I:10.1088/1674-1137/ad3c2.

Quantifying the strength of magnetic fields using baryon electric charge correlation

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nuclear Science and Techniques 2024年第8期35卷 5-8页

作者： Xu‑Guang Huang physics Department and center for Particle physics and Field Theory Fudan UniversityShanghai 200433China Key Laboratory of nuclear physics and Ion‑beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China Shanghai Research center for theoretical {2. physics National Natural Science Foundation of China and Fudan UniversityShanghai 200438China

Although heavy-ion collisions generate strong magnetic fields,their direct measurement is a challenging task.A new observable,the baryon electric charge correlation,was recently found to be sensitive to the magnetic field strength and thus could be used as a magnetometer for heavy-ion ***,this observable may shed light on the equation of state and phase structure of quantum chromodynamics(QCD)under magnetic *** and understanding the phase structure of quantum chromodynamics(QCD)is important in contemporary physics[1].

关键词： charge observable magnetic

Thermodynamic nature of black holes in coexistence region

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Science China(physics,Mechanics & Astronomy) 2024年第5期67卷 27-32页

作者： Shao-Wen Wei Yu-Xiao Liu Lanzhou center for theoretical {2. Key Laboratory of Theoretical Physics of Gansu Provinceand Key Laboratory of Quantum Theory and Applications of Mo ELanzhou UniversityLanzhou 730000China Institute of theoretical physics&Research {2. of Gravitation Lanzhou UniversityLanzhou 730000China

Studying the system state of coexistence regions will peek into to reveal microscopic interactions between different phases of a thermodynamic ***,there is no effective method to study thermodynamic nature of the coexistence black hole regions for the failure of the equation of *** at these coexistence states,in this work,we develop a general approach by introducing two new ratio *** first one is the ratio of the horizon radii of the saturated coexistence small and large black holes,and the second one measures that of the small black hole molecule number to the total molecule *** demonstrate that the first parameter can serve as an order parameter to characterize the first-order phase *** study also shows that the black hole state in the coexistence region is uniquely determined by these two introduced parameters bounded between 0 and *** results are quite significant in the analytical study of phase transition and the microscopic nature of black hole in the coexistence regions.

关键词： transition. state. thermodynamic

Applying deep learning technique to chiral magnetic wave search

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Chinese physics C 2024年第8期48卷 170-176页

作者： Yuan-Sheng Zhao Xu-Guang Huang physics Department and center for Particle physics and Field Theory Fudan UniversityShanghai 200433China Key Laboratory of nuclear physics and Ion-beam Application(MOE) Fudan UniversityShanghai 200433China Shanghai Research center for theoretical {2. physics National Natural Science Foundation of China and Fudan UniversityShanghai 200438China

The chiral magnetic wave(CMW)is a collective mode in quark-gluon plasma originated from the chiral magnetic effect(CME)and chiral separation *** detection in heavy-ion collisions is challenging owing to significant background ***[*** et al.,***.C 106,L051901(2.2.)],we constructed a neural network that accurately identifies the CME-related signal from the final-state pion *** this study,we have generalized this neural network to the case of CMW *** show that,after an updated training,the neural network effectively recognizes the CMW-related ***,we have assessed the performance of the neural network in comparison with other known methods for CMW search.

关键词： deep learning chiral magnetic wave relativistic heavy-ion collisions

Spin asymmetry and dipole moments inτ-pair production with ultraperipheral heavy ion collisions

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Science China(physics,Mechanics & Astronomy) 2024年第8期67卷 15-21页

作者： Dingyu Shao Bin Yan Shu-Run Yuan Cheng Zhang Department of physics Center for Field Theory and Particle PhysicsFudan UniversityShanghai 200433China Key Laboratory of nuclear physics and Ion-beam Application(MOE) Fudan UniversityShanghai 200433China Shanghai Research center for theoretical {2. physics National Natural Science Foundation of China(NSFC)and Fudan UniversityShanghai 200438China Institute of High Energy physics Chinese Academy of SciencesBeijing 100049China School of physics Peking UniversityBeijing 100871China

The anomalous magnetic(MDM)and electric(EDM)dipole moments of theτlepton serve as crucial indicators of new physics beyond the standard *** azimuthal angular asymmetry as a novel tool in ultraperipheral collisions(UPCs),we attain unparalleled precision in the study of these key *** by the highly linear polarization of coherent photons,this method uniquely enables both the MDM and EDM to contribute to the cos 2.angular distribution in similar ***,our approach substantially narrows the parameter space,excluding more than half of it compared to expected UPC-based measurements reliant solely on the total *** method not only provides improved constraints but also minimizes the need for additional theoretical assumptions,and offers a novel avenue to probe the EDM effects.

关键词： ultraperipheral collisions magnetic and electric dipole moments spin asymmetry

New quantification of symmetry energy from neutron skin thicknesses of 48Ca and 2.8Pb

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nuclear Science and Techniques 2024年第10期35卷 217-225页

作者： Rong An Shuai Sun Li-Gang Cao Feng-Shou Zhang School of physics Ningxia University Key Laboratory of Beam Technology of the Ministry of Education College of Nuclear Science and TechnologyBeijing Normal University Key Laboratory of Beam Technology of the Ministry of Education Institute of Radiation TechnologyBeijing Academy of Science and Technology center of theoretical {2. physics National Laboratory of the Heavy Ion Accelerator of Lanzhou

Precise knowledge of the nuclear symmetry energy can be tentatively calibrated using multimessenger *** neutron skin thickness of a heavy nucleus is one of the most sensitive indicators for probing the isovector components of effective interactions in asymmetric nuclear *** studies have suggested that the experimental data from the CREX and PREX2.collaborations are not mutually compatible with existing nuclear *** this study,we review the quantification of the slope parameter of the symmetry energy L from the neutron skin thicknesses of48Ca *** energy density functionals classified by various isoscalar incompressibility coefficients K were employed to evaluate the bulk properties of finite *** calculated results suggest that the slope parameter L deduced from2.8Pb is sensitive to the compression modulus of symmetric nuclear matter,but not that *** effective parameter sets classified by K=2.0 MeV can provide an almost overlapping range of L from48Ca and2.8Pb.

关键词： Energy density functional Neutron skin thickness nuclear symmetry energy

Domain wall network:A dual solution for gravitational waves and Hubble tension?

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Science China(physics,Mechanics & Astronomy) 2024年第11期67卷 39-46页

作者： Ligong Bian Shuailiang Ge Changhong Li Jing Shu Junchao Zong Department of physics and Chongqing Key Laboratory for Strongly Coupled physics Chongqing UniversityChongqing 401331China center for High Energy physics Peking UniversityBeijing 100871China School of physics and State Key Laboratory of nuclear physics and Technology Peking UniversityBeijing 100871China Department of Astronomy Key Laboratory of Astroparticle Physics of Yunnan ProvinceSchool of Physics and AstronomyYunnan UniversityKunming 650091China Beijing Laser Acceleration Innovation center Beijing 101400China Department of physics Nanjing UniversityNanjing 210093China CAS Key Laboratory of theoretical physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China

We explore the possibility that domain wall networks generate the stochastic gravitational wave background(SGWB) observed as a strong common power-law process in the Data Release-2.of Parkes Pulsar Timing Array. We find that a broad range of parameters, specifically wall tension around σ_(DW)^(2.-414 TeV)^(3) and wall-decay temperature within T_(d) ~ 2.-2.7 MeV, can explain this phenomenon at a 68% credible level. Meanwhile, the same parameters could ease the Hubble tension if particles from these domain wall networks decay into dark radiation. We establish a direct analytical relationship, ΩGW(f_(p), T_(0))h^(2.~ Ω_(rad)h^(2.(Ω_νΩN_(eff))^(2.,to illustrate this coincidence, underlining its importance in the underlying physics and potential applicability to a wider range of models and data. Conversely, if the common power-law process is not attributed to domain wall networks, our findings impose tight limits on the wall tension and decay temperature.

关键词： domain wall gravitational waves Hubble tension