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, f...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.展开更多
Observing GeV gamma-rays is an important goal of the DArk Matter Particle Explorer(DAMPE)for indirect dark matter searching and high energy astrophysics. In this work, we present a set of accurate instrument response ...Observing GeV gamma-rays is an important goal of the DArk Matter Particle Explorer(DAMPE)for indirect dark matter searching and high energy astrophysics. In this work, we present a set of accurate instrument response functions for DAMPE(DmpIRFs) including the effective area, point-spread function and energy dispersion, which are crucial for gamma-ray data analysis based on statistics from simulation data. A dedicated software named DmpST is developed to facilitate the scientific analyses of DAMPE gamma-ray data. Considering the limited number of photons and angular resolution of DAMPE, the maximum likelihood method is adopted in DmpST to better disentangle different source components. The basic mathematics and framework regarding this software are also introduced in this paper.展开更多
The Plastic Scintillator Detector(PSD) onboard the DArk Matter Particle Explorer(DAMPE)is designed to measure cosmic ray charge(Z) and to act as a veto detector for gamma ray identification.To fully exploit the charge...The Plastic Scintillator Detector(PSD) onboard the DArk Matter Particle Explorer(DAMPE)is designed to measure cosmic ray charge(Z) and to act as a veto detector for gamma ray identification.To fully exploit the charge identification potential of PSD and to enhance its capability to identify gamma ray events, we develop an alignment method for the PSD. The path length of a given track in the volume of a PSD bar is derived taking into account the shift and rotation alignment corrections. By examining energy spectra of corner-passing events and fully contained events, position shifts and rotations of all PSD bars are obtained, and are found to be on average about 1 mm and 0.0015 radian respectively. To validate the alignment method, we introduce artificial shifts and rotations of PSD bars into the detector simulation.These shift and rotation parameters can be recovered successfully by the alignment procedure. As a result of the PSD alignment procedure, the charge resolution of the PSD is improved from 4% to 8%, depending on the nuclei.展开更多
If X-ray flashes (XRFs) and X-ray rich Gamma-ray Bursts (XRRGs) have the same origin as the Gamma-ray bursts (GRBs) but are viewed off-center from structured jets, their early afterglows may differ from those of...If X-ray flashes (XRFs) and X-ray rich Gamma-ray Bursts (XRRGs) have the same origin as the Gamma-ray bursts (GRBs) but are viewed off-center from structured jets, their early afterglows may differ from those of GRBs, and when the ultra-relativistic outflow inter- acts with the surrounding medium, there are two shocks formed, a forward shock (FS), and a reverse shock (RS). We calculate numerically the early afterglow powered by uniform jets, Gaussian jets and power-law jets in the forward-reverse shock scenario. A set of differential equations govern the dynamical evolution. The synchrotron self-Compton effect has been taken into account in the calculation. In the uniform jets, the very early afterglows of XRRGs and XRFs are significantly lower than the GRBs and the observed peak times of RS emission are later in the interstellar medium environment. The RS components in XRRGs and XRFs are difficult to detect, but in the stellar wind environment, the reduction of the very early flux and the delay of the RS peak time are not so remarkable. In nonuniform jets (Gaussian and power-law jets), where there are emission materials on the line of sight, the very early light curve resembles equivalent isotropic ejecta in general although the RS flux decay index shows notable deviations if the RS is relativistic (in stellar wind).展开更多
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...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.展开更多
Studies have proposed that there is evidence for cosmological coupling of black holes(BHs)with an index of k≈3;hence,BHs serve as the astrophysical source of dark energy.However,the data sample is limited for the red...Studies have proposed that there is evidence for cosmological coupling of black holes(BHs)with an index of k≈3;hence,BHs serve as the astrophysical source of dark energy.However,the data sample is limited for the redshifts of≤2.5.In recent years,the James Webb Space Telescope(JWST)has detected many high-redshift active galactic nuclei(AGNs)and quasars.Among the JWST NIRSpec-/NIRCam-resolved AGNs,three are determined to be in early-type host galaxies with a redshift of z~4.5-7.However,their M_(*)and MBH are in tension with the predicted cosmological coupling of black holes with k=3 at a confidence level of~2σ,which challenges the hypothesis that BHs serve as the origin of dark energy.Future work on high-redshift AGNs using the JWST will further assess such a hypothesis by identifying more early-type host galaxies in the higher mass range.展开更多
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 ge...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.展开更多
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 orig...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.展开更多
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 cos...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.展开更多
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 detecti...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.展开更多
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(...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.展开更多
超对称模型是最受关注的新物理模型之一.最近Fermi实验室E989实验以更高置信度报道了谬轻子g-2反常,此前Fermi-LAT观测到银河系中心的伽马射线超出,AMS-02的反质子数据中也存在超出的迹象.本文指出,在次超对称模型下这3种反常可以得到...超对称模型是最受关注的新物理模型之一.最近Fermi实验室E989实验以更高置信度报道了谬轻子g-2反常,此前Fermi-LAT观测到银河系中心的伽马射线超出,AMS-02的反质子数据中也存在超出的迹象.本文指出,在次超对称模型下这3种反常可以得到自洽的解释.在详细考虑了希格斯质量、B物理、对撞机、暗物质残留密度和暗物质直接探测等限制之后,作者发现暗物质粒子的质量约为60 Ge V.另外,文章特别指出,该参数区间可被正在开展的暗物质直接探测实验有效地予以检验.展开更多
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...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.展开更多
Precise measurements of the energy spectra of cosmic rays(CRs)show various kinds of features deviating from single power-laws,which give very interesting and important implications on their origin and propagation.Prev...Precise measurements of the energy spectra of cosmic rays(CRs)show various kinds of features deviating from single power-laws,which give very interesting and important implications on their origin and propagation.Previous measurements from a few balloon and space experiments indicate the existence of spectral softenings around 10 TV for protons(and probably also for Helium nuclei).Very recently,the DArk Matter Particle Explorer(DAMPE)measurement about the proton spectrum clearly reveals such a softening with a high significance.Here we study the implications of these new measurements,as well as the groundbased indirect measurements,on the origin of CRs.We find that a single component of CRs fails to fit the spectral softening and the air shower experiment data simultaneously.In the framework of multiple components,we discuss two possible scenarios,the multiple source population scenario and the background plus nearby source scenario.Both scenarios give reasonable fits to the wide-band data from TeV to 100 PeV energies.Considering the anisotropy observations,the nearby source model is favored.展开更多
基金Supported by the National Natural Science Foundation of China.
文摘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.
基金supported in part by the National Key Program for Research and Development (2016YFA0400200)the Strategic Priority Research Program of Chinese Academy of Sciences (XDB23040000)+3 种基金the 13th Five-year Informatization Plan of Chinese Academy of Sciences (XXH13506)the National Natural Science Foundation of China (Nos. U1631111, U1738123, U1738136 and U1738210)Youth Innovation Promotion Association of Chinese Academy of Sciencesthe Young Elite Scientists Sponsorship Program
文摘Observing GeV gamma-rays is an important goal of the DArk Matter Particle Explorer(DAMPE)for indirect dark matter searching and high energy astrophysics. In this work, we present a set of accurate instrument response functions for DAMPE(DmpIRFs) including the effective area, point-spread function and energy dispersion, which are crucial for gamma-ray data analysis based on statistics from simulation data. A dedicated software named DmpST is developed to facilitate the scientific analyses of DAMPE gamma-ray data. Considering the limited number of photons and angular resolution of DAMPE, the maximum likelihood method is adopted in DmpST to better disentangle different source components. The basic mathematics and framework regarding this software are also introduced in this paper.
基金funded by the National Key Program for Research and Development (2016YFA0400200)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB23040000)the National Natural Science Foundation of China (Grant Nos. 11773086, U1738205, U1738127, 11673021, 11673047, 11673075, 11643011, 11773085, U1738207, U1738138, U1631111, U1738129 and 11703062)
文摘The Plastic Scintillator Detector(PSD) onboard the DArk Matter Particle Explorer(DAMPE)is designed to measure cosmic ray charge(Z) and to act as a veto detector for gamma ray identification.To fully exploit the charge identification potential of PSD and to enhance its capability to identify gamma ray events, we develop an alignment method for the PSD. The path length of a given track in the volume of a PSD bar is derived taking into account the shift and rotation alignment corrections. By examining energy spectra of corner-passing events and fully contained events, position shifts and rotations of all PSD bars are obtained, and are found to be on average about 1 mm and 0.0015 radian respectively. To validate the alignment method, we introduce artificial shifts and rotations of PSD bars into the detector simulation.These shift and rotation parameters can be recovered successfully by the alignment procedure. As a result of the PSD alignment procedure, the charge resolution of the PSD is improved from 4% to 8%, depending on the nuclei.
基金Supported by the National Natural Science Foundation of China.
文摘If X-ray flashes (XRFs) and X-ray rich Gamma-ray Bursts (XRRGs) have the same origin as the Gamma-ray bursts (GRBs) but are viewed off-center from structured jets, their early afterglows may differ from those of GRBs, and when the ultra-relativistic outflow inter- acts with the surrounding medium, there are two shocks formed, a forward shock (FS), and a reverse shock (RS). We calculate numerically the early afterglow powered by uniform jets, Gaussian jets and power-law jets in the forward-reverse shock scenario. A set of differential equations govern the dynamical evolution. The synchrotron self-Compton effect has been taken into account in the calculation. In the uniform jets, the very early afterglows of XRRGs and XRFs are significantly lower than the GRBs and the observed peak times of RS emission are later in the interstellar medium environment. The RS components in XRRGs and XRFs are difficult to detect, but in the stellar wind environment, the reduction of the very early flux and the delay of the RS peak time are not so remarkable. In nonuniform jets (Gaussian and power-law jets), where there are emission materials on the line of sight, the very early light curve resembles equivalent isotropic ejecta in general although the RS flux decay index shows notable deviations if the RS is relativistic (in stellar wind).
基金the National Natural Science Foundation of China.
文摘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.
基金support of Cyrus Chun Ying Tang Foundationssupported by the National Natural Science Foundation of China(Grant Nos.11921003,and 12233011)the Chinese Academy of Sciences via the Key Research Program of Frontier Sciences(Grant No.QYZDJ-SSWSYS024)。
文摘Studies have proposed that there is evidence for cosmological coupling of black holes(BHs)with an index of k≈3;hence,BHs serve as the astrophysical source of dark energy.However,the data sample is limited for the redshifts of≤2.5.In recent years,the James Webb Space Telescope(JWST)has detected many high-redshift active galactic nuclei(AGNs)and quasars.Among the JWST NIRSpec-/NIRCam-resolved AGNs,three are determined to be in early-type host galaxies with a redshift of z~4.5-7.However,their M_(*)and MBH are in tension with the predicted cosmological coupling of black holes with k=3 at a confidence level of~2σ,which challenges the hypothesis that BHs serve as the origin of dark energy.Future work on high-redshift AGNs using the JWST will further assess such a hypothesis by identifying more early-type host galaxies in the higher mass range.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFF0503304)the National Natural Science Foundation of China(Grant No.11921003)+2 种基金the New Cornerstone Science Foundation through the XPLORER PRIZEthe Chinese Academy of Sciencesthe Entrepreneurship and Innovation Program of Jiangsu Province。
文摘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.
基金supported by the National Natural Science Foundation of China(Grant Nos.11921003,and U1738210)China Postdoctoral Science Foundation(Grant No.2020M681757)Key Research Program of the Chinese Academy of Sciences(Grant No.XDPB15)。
文摘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.
基金supported by the National Key Research and Development Program of China(No.2021YFA0718404)the National Natural Science Foundation of China(Nos.12220101003 and 12103094)+1 种基金the Project for Young Scientists in Basic Research of Chinese Academy of Sciences(No.YSBR-061)The calculation was partially done on the Cosmology Simulation Database(CSD)of the National Basic Science Data Center(NBSDC-DB-10).
文摘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.
基金The DAMPE mission was funded by the strategic priority science and technology projects in space science of Chinese Academy of SciencesIn China the data analysis is supported in part by the National Key Research and Development Program of China(No.2016YFA0400200)+2 种基金the National Natural Science Foundation of China(Nos.U1738210,U1738123,U1738205,U1738138,11921003,and 12003074)the Youth Innovation Promotion Association CAS,the Key Research Program of the Chinese Academy of Sciences Grant(No.ZDRW-KT-2019-5)the Entrepreneurship and Innovation Program of Jiangsu Province.
文摘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.
基金This work was supported by the National Key Research and Development Program of China(Nos.2018YFA0404203 and 2016YFA0400200)the National Natural Science Foundation of China(Nos.11722328,11525313,U1738205,and 11851305)the 100 Talents program of Chinese Academy of Sciences,and the Program for Innovative Talents and Entrepreneur in Jiangsu.
文摘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.
基金the National Natural Science Foundation of China(U1738210,12047560,and 11773075)China Post-doctoral Science Foundation(2020M681757)。
文摘超对称模型是最受关注的新物理模型之一.最近Fermi实验室E989实验以更高置信度报道了谬轻子g-2反常,此前Fermi-LAT观测到银河系中心的伽马射线超出,AMS-02的反质子数据中也存在超出的迹象.本文指出,在次超对称模型下这3种反常可以得到自洽的解释.在详细考虑了希格斯质量、B物理、对撞机、暗物质残留密度和暗物质直接探测等限制之后,作者发现暗物质粒子的质量约为60 Ge V.另外,文章特别指出,该参数区间可被正在开展的暗物质直接探测实验有效地予以检验.
基金supported by the National Key R&D Program of China(Grant No.2021YFC2203100)the National Natural Science Foundation of China(Grant Nos.11921003,11961131007,and 11653002)+1 种基金the CAS Project for Young Scientists in Basic Research(Grant No.YSBR-006)the USTC Research Funds of the Double First-Class Initiative。
文摘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.
基金the Na-tional Key Research and Development Program of China(No.2016YFA0400200)the National Natural Science Foundation of China(Nos.11722328,11525313,U1738205,and 11851305)the 100 Talents Program of Chinese Academy of Sciences.
文摘Precise measurements of the energy spectra of cosmic rays(CRs)show various kinds of features deviating from single power-laws,which give very interesting and important implications on their origin and propagation.Previous measurements from a few balloon and space experiments indicate the existence of spectral softenings around 10 TV for protons(and probably also for Helium nuclei).Very recently,the DArk Matter Particle Explorer(DAMPE)measurement about the proton spectrum clearly reveals such a softening with a high significance.Here we study the implications of these new measurements,as well as the groundbased indirect measurements,on the origin of CRs.We find that a single component of CRs fails to fit the spectral softening and the air shower experiment data simultaneously.In the framework of multiple components,we discuss two possible scenarios,the multiple source population scenario and the background plus nearby source scenario.Both scenarios give reasonable fits to the wide-band data from TeV to 100 PeV energies.Considering the anisotropy observations,the nearby source model is favored.