High-energy photons may oscillate with axion-like particles(ALPs)when they propagate through the Milky Way's magnetic field,resulting in an alteration in the observed photon energy spectrum.Ultra-high energy gamma...High-energy photons may oscillate with axion-like particles(ALPs)when they propagate through the Milky Way's magnetic field,resulting in an alteration in the observed photon energy spectrum.Ultra-high energy gamma-ray spectra,measured by the Large High Altitude Air Shower Observatory(LHAASO)up to O(1)PeV,provide a promising opportunity to investigate the ALP-photon oscillation effect.In this study,we utilize the gamma-ray spectra of four Galactic sources measured by the LHAASO,that is,the Crab Nebula,LHAASO J2226+6057,LHAASO J1908+0621,and LHAASO J1825-1326,to explore this effect.We employ the CLsmethod to set constraints on the ALP parameters.Our analysis of the observations of the four sources reveals that the ALPphoton coupling gaγis constrained to be smaller than 1.4×10^(-1)0GeV^(-1)for an ALP mass of~4×10^(-7)eV at 95%C.L.Combining the observations of the Crab Nebula from the LHAASO and other experiments,we find that the ALP-photon coupling may be set to approximately 7.5×10^(-11)GeV^(-1)for an ALP mass of~4×10^(-7)eV,which is similar to the CAST constraint.展开更多
Numerous simulations indicate that a large number of subhalos should be hosted by the Milky Way.The potential existence of a nearby subhalo could have important implications for our understanding of dark matter(DM)ann...Numerous simulations indicate that a large number of subhalos should be hosted by the Milky Way.The potential existence of a nearby subhalo could have important implications for our understanding of dark matter(DM)annihilation.In this study,we investigate the hypothetical presence of a nearby subhalo and set the upper limits on the DM annihilation cross section by analyzing the cosmic-ray antiproton spectrum.By presenting the ratios of annihilation cross section limits for scenarios with and without a nearby subhalo,we can quantitatively evaluate the potential impact of the nearby subhalo on the limits of the DM annihilation cross section.The impacts of the concentration model and the subhalo probability distribution have been considered.We explore the antiproton contribution of the potential nearby DM subhalo accounting for the DAMPE e+spectrum at~1.4 TeV and find that the current AMS-02 antiproton results do not limit this contribution.展开更多
为解决网络故障恢复期间的反应时间过长的问题,将软件定义网络(software defined networking,SDN)网络架构引入到网络故障恢复的策略设计中,对比现有故障恢复领域研究的优势和不足,提出一种基于SDN的故障恢复方法。通过对整网拓扑结构...为解决网络故障恢复期间的反应时间过长的问题,将软件定义网络(software defined networking,SDN)网络架构引入到网络故障恢复的策略设计中,对比现有故障恢复领域研究的优势和不足,提出一种基于SDN的故障恢复方法。通过对整网拓扑结构进行分域,采用无向图环路算法(undirected graph loop algorithm,UGLA)计算当前网络拓扑中的所有环路;根据UGLA,设计链路评估方法,选择最优故障备份转发路径转发数据流量。故障恢复实验数据的分析结果表明,该方法可提高交换机流表匹配效率,减少故障恢复时间,保障业务的带宽需求和服务质量。展开更多
基金Xiao-Jun Bi is supported by the National Natural Science Foundation of China(12175248)Xiaoyuan Huang is supported by the National Key Research and Development Program of China(2022YFF0503304)+2 种基金the National Natural Science Foundation of China(12322302)the Project for Young Scientists in Basic Research of Chinese Academy of Sciences(YSBR-061)the Chinese Academy of Sciences,and the Entrepreneurship and Innovation Program of Jiangsu Province,China.
文摘High-energy photons may oscillate with axion-like particles(ALPs)when they propagate through the Milky Way's magnetic field,resulting in an alteration in the observed photon energy spectrum.Ultra-high energy gamma-ray spectra,measured by the Large High Altitude Air Shower Observatory(LHAASO)up to O(1)PeV,provide a promising opportunity to investigate the ALP-photon oscillation effect.In this study,we utilize the gamma-ray spectra of four Galactic sources measured by the LHAASO,that is,the Crab Nebula,LHAASO J2226+6057,LHAASO J1908+0621,and LHAASO J1825-1326,to explore this effect.We employ the CLsmethod to set constraints on the ALP parameters.Our analysis of the observations of the four sources reveals that the ALPphoton coupling gaγis constrained to be smaller than 1.4×10^(-1)0GeV^(-1)for an ALP mass of~4×10^(-7)eV at 95%C.L.Combining the observations of the Crab Nebula from the LHAASO and other experiments,we find that the ALP-photon coupling may be set to approximately 7.5×10^(-11)GeV^(-1)for an ALP mass of~4×10^(-7)eV,which is similar to the CAST constraint.
基金Supported by the Science&Technology Development Fund of Tianjin Education Commission for Higher Education(2020KJ003)。
文摘Numerous simulations indicate that a large number of subhalos should be hosted by the Milky Way.The potential existence of a nearby subhalo could have important implications for our understanding of dark matter(DM)annihilation.In this study,we investigate the hypothetical presence of a nearby subhalo and set the upper limits on the DM annihilation cross section by analyzing the cosmic-ray antiproton spectrum.By presenting the ratios of annihilation cross section limits for scenarios with and without a nearby subhalo,we can quantitatively evaluate the potential impact of the nearby subhalo on the limits of the DM annihilation cross section.The impacts of the concentration model and the subhalo probability distribution have been considered.We explore the antiproton contribution of the potential nearby DM subhalo accounting for the DAMPE e+spectrum at~1.4 TeV and find that the current AMS-02 antiproton results do not limit this contribution.
