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Is the W-boson mass enhanced by the axion-like particle,dark photon,or chameleon dark energy?

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Science China(Physics,Mechanics & Astronomy) 2022年第12期65卷 145-152页

作者： Guan-Wen Yuan Lei Zu Lei Feng yi-Fu Cai yi-zhong fan Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei230026China Department of Astronomy School of Physical SciencesUniversity of Science and Technology of ChinaHefei230026China CAS Key Laboratory for Researches in Galaxies and Cosmology University of Science and Technology of ChinaHefei230026China

The W-boson mass(m W=(80.4335±0.0094)Ge V)measured by the Collider Detector at Fermilab Collaboration is greater than the standard model(SM)prediction at a confidence level of 7σ,strongly suggesting the presence of new particles or fields.In the literature,various new particles and/or fields have been introduced to explain the astrophysical and experimental data,and their presence,in principle,may also enhance the W-boson mass.In this study,we investigate axion-like particle(ALP),dark photon(DP),and chameleon dark energy(DE)models for a solution to the W-boson mass excess.We find that the ALP and DP interpretations have been significantly narrowed down by global electroweak fits.The possibility of attributing the W-boson mass anomaly to the chameleon DE is ruled out by other experiments.

关键词： W-boson mass axion-like particle dark photon chameleon dark energy

The nanohertz stochastic gravitational wave background from cosmic string loops and the abundant high redshift massive galaxies

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Science China(Physics,Mechanics & Astronomy) 2023年第12期66卷 11-19页

作者： Ziwei Wang Lei Lei Hao Jiao Lei Feng yi-zhong fan Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China Department of Physics McGill UniversityMontreal H3A 2T8Canada

Recently,pulsar timing array(PTA)experiments have provided compelling evidence for the existence of the nanohertz stochastic gravitational wave background(SGWB).In this work,we demonstrated that cosmic string loops generated from cosmic global strings offer a viable explanation for the observed nanohertz SGWB data,requiring a cosmic string tension parameter of log(Gμ)~-12 and a loop number density of log N~4.Additionally,we revisited the impact of cosmic string loops on the abundance of massive galaxies at high redshifts.However,our analysis revealed challenges in identifying a consistent parameter space that can concurrently explain both the SGWB data and observations from the James Webb Space Telescope.This indicates the necessity for either extending the existing model employed in this research or acknowledging distinct physical origins for these two phenomena.

关键词： nanohertz stochastic gravitational-wave background cosmic string loop JamesWebb Space Telescope galaxy formation

The Synchrotron-self-Compton Radiation Accompanying Shallow Decaying X-Ray Afterglow:the Case of GRB 940217

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Chinese Journal of Astronomy and Astrophysics 2007年第4期7卷 509-515页

作者： Da-Ming Wei yi-zhong fan Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008 National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 Joint Center for Particle Nuclear Physics and Cosmology of Purple Mountain Observatory - Nanjing University Nanjing 210008 The Racah Inst. of Physics Hebrew University Jerusalem 91904 Israel Golda Meir Fellow

High energy emission （〉 tens MeV） of Gamma-Ray Bursts （GRBs） provides an important clue on the physical processes occurring in GRBs that may be correlated with the GRB early afterglow. A shallow decline phase has been well identified in about half of Swift Gamma-ray Burst x-ray afterglows. The widely considered interpretation inv.olves a significant energy injection and possibly time-evolving shock parameter（s）. We calculate the synchrotron-self-Compton （SSC） radiation of such an external forward shock and show that it could explain the well-known long term high energy （i.e., tens MeV to GeV） afterglow of GRB 940217. We propose that cooperation of Swift and GLAST will help to reveal the nature of GRBs.

关键词： gamma-rays： bursts - ISM： jets and outflows - radiation mechanisms： non-thermal

Short-living Supermassive Magnetar Model for the Early X-ray Flares Following Short GRBs

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Chinese Journal of Astronomy and Astrophysics 2006年第5期6卷 513-516页

作者： Wei-Hong Gao yi-zhong fan Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing 210008 The Racah Inst. of Physics Hebrew University Jerusalem 91904Israel Purple Mountain Observatory Chinese Academy of Sciences Nanjing210008 Lady Davis Fellow

We suggest a short-lived supermassive magnetar model to account for the X-ray flares following short γ-ray bursts. In this model the central engine of the short γ-ray bursts is a supermassive millisecond magnetar, formed in coalescence of double neutron stars. The X-ray flares are powered by the dipole radiation of the magnetar. When the magnetar has lost a significant part of its angular momentum, it collapses to a black hole and the X-ray flares cease abruptly.

关键词： Gamma-rays bursts -- radiation mechanisms nonthermal -- magnetic fields -- stars neutron- stars rotation

Optimal gamma-ray selections for monochromatic line searches with DAMPE

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Frontiers of physics 2022年第3期17卷 1-6页

作者： Zun-Lei Xu Kai-Kai Duan Wei Jiang Shi-Jun Lei Xiang Li Zhao-Qiang Shen Tao Ma Meng Su Qiang Yuan Chuan Yue yi-zhong fan Jin Chang Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China

The DArk Matter Particle Explorer (DAMPE) is a space high-energy cosmic-ray detector covering a wide energy band with a high energy resolution. One of the key scientific goals of DAMPE is to carry out indirect detection of dark matter by searching for high-energy gamma-ray line structure. To promote the sensitivity of gamma-ray line search with DAMPE, it is crucial to improve the acceptance and energy resolution of gamma-ray photons. In this paper, we quantitatively proved that the photon sample with the largest ratio of acceptance to energy resolution is optimal for line search. We therefore developed a line-search sample specifically optimized for the line-search. Meanwhile, in order to increase the statistics, we also selected the so-called BGO-only photons that convert into e^(+)e^(-) pairs only in the BGO calorimeter. The standard, the line-search, and the BGO-only photon samples are then tested for line-search individually and collectively. The results show that a significantly improved limit could be obtained from an appropriate combination of the date sets, and the increase is about 20% for the highest case compared with using the standard sample only.

关键词： DArk Matter Particle Explorer(DAMPE) gamma-ray line-search

NMSSM neutralino dark matter for CDFⅡW-boson mass and muon g-2 and the promising prospect of direct detection

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Science China(Physics,Mechanics & Astronomy) 2023年第3期66卷 169-177页

作者： Tian-Peng Tang Murat Abdughani Lei Feng Yue-Lin Sming Tsai Jian Wu yi-zhong fan Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210033China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China School of Physical Science and Technology Xinjiang UniversityUrumqi 830046China Joint Center for Particle Nuclear Physics and CosmologyNanjing University-Purple Mountain ObservatoryNanjing 210093China

Two experiments from the Fermilab, E989 and CDF II, have reported two anomalies for muon g-2 and W-boson mass that may indicate the new physics at the low energy scale. Here we examine the possibility of a common origin of these two anomalies in the Next-to-Minimal Supersymmetric Standard Model. Considering various experimental and astrophysical constraints such as the Higgs mass, collider data, flavor physics, dark matter relic density, and direct detection experiments, we find that lighter electroweakinos and sleptons can generate sufficient contributions to muon g-2 and mW. Moreover, the corresponding bino-like neutralino dark matter mass is in the ~ 180-280 Ge V range. Interestingly, the favored dark matter(DM) mass region can soon be entirely probed by ongoing direct detection experiments like Panda X-4T, XENONn T, LUX-ZEPLIN, and DARWIN.

关键词： supersymmetry dark matter W-boson muon g-2

Nearby source interpretation of differences among light and medium composition spectra in cosmic rays

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Frontiers of physics 2021年第2期16卷 195-200页

作者： Qiang Yuan Bing-Qiang Qiao yi-Qing Guo yi-zhong fan Xiao-Jun Bi Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China Center for High Energy Physics Peking UniversityBeijing 100871China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China

Recently the AMS-02 reported the precise measurements of the energy spectra of medium-mass compositions(Neon,Magnesium,Silicon)of primary cosmic rays,which reveal different properties from those of light compositions(Helium,Carbon,Oxygen).Here we propose a nearby source scenario,together with the background source contribution,to explain the newly measured spectra of cosmic ray Ne,Mg,Si,and particularly their differences from that of He,C,O.Their differences at high energies can be naturally accounted for by the element abundance of the nearby source.Specifically,the abundance ratio of the nearby source to the background of the Ne,Mg,Si elements is lower by a factor of~1.7 than that of the He,C,O elements.Such a diference could be due to the abundance difference of the stellar evolution of the progenitor star or the acceleration process/environment,of the nearby source.This scenario can simultaneously explain the high-energy spectral softening features of cos-mic ray spectra revealed recently by CREAM/NUCLEON/DAMPE,as well as the energy-dependent behaviors of the large scale anisotropies.It is predicted that the dipole anisotropy amplitudes below PeV energies of the Ne,Mg,Si group are smaller than that of the He,C,O group,which can be tested with future measurements.

关键词： cosmic rays spectra and anisotropies

镜像量子色动力学相变解释纳赫兹随机引力波背景

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Science Bulletin 2024年第6期69卷 741-746页

作者：祖磊张弛李垚钰顾玉超蔡岳霖范一中 Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China

Several Pulsar Timing Array(PTA)Collaborations have recently provided strong evidence for a n Hz Stochastic Gravitational-Wave Background(SGWB).Here we investigate the implications of a firstorder phase transition occurring within the early Universe's dark quantum chromodynamics epoch,specifically within the framework of the mirror twin Higgs dark sector model.Our analysis indicates a distinguishable SGWB signal originating from this phase transition,which can explain the measurements obtained by PTAs.Remarkably,a significant portion of the parameter space for the SGWB signal also effectively resolves the existing tensions in both the H_(0) and S_(8) measurements in Cosmology.This intriguing correlation suggests a possible common origin of these three phenomena for 0.2<ΔN_(eff)<0.5,where the mirror dark matter component constitutes less than 30% of the total dark matter abundance.Nextgeneration CMB experiments such as CMB-S4 can test this parameter region.

关键词： Mirror twin Higgs Dark matter Phase transition Gravitational wave Pulsar timing array

Interpretations of the cosmic ray secondary-toprimary ratios measured by DAMPE

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Frontiers of physics 2023年第4期18卷 95-110页

作者： Peng-Xiong Ma Zhi-Hui Xu Qiang Yuan Xiao-Jun Bi yi-zhong fan Igor VMoskalenko Chuan Yue Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China W.W.Hansen Experimental Physics Laboratory and Kavli Institute for Particle Astrophysics and Cosmology Stanford UniversityStanfordCA 94305USA

Precise measurements of the boron-to-carbon and boron-to-oxygen ratios by DAMPE show clear hardenings around 100 GeV/n,which provide important implications on the production,propagation,and interaction of Galactic cosmic rays.In this work we investigate a number of models proposed in literature in light of the DAMPE findings.These models can roughly be classified into two classes,driven by propagation effects or by source ones.Among these models discussed,we find that the re-acceleration of cosmic rays,during their propagation,by random magnetohydrodynamic waves may not reproduce sufficient hardenings of B/C and B/O,and an additional spectral break of the diffusion coefficient is required.The other models can properly explain the hardenings of the ratios.However,depending on simplifications assumed,the models differ in their quality in reproducing the data in a wide energy range.The models with significant re-acceleration effect will under-predict low-energy antiprotons but over-predict low-energy positrons,and the models with secondary production at sources over-predict high-energy antiprotons.For all models high-energy positron excess exists.

关键词： cosmic rays propagation