Search for gamma-ray line signals around the black hole at the galactic center with DAMPE observation

The adiabatic growth of a black hole(BH)may enhance the dark matter(DM)density surrounding it,causing a spike in the DM density profile.The spike around the supermassive BH at the center of the Milky Way may lead to a dramatic enhancement of the gamma-ray flux of DM annihilation from the galactic center(GC).In this work,we analyze the gamma-ray data of the innermost region(i.e.,the inner 1°)of the GC to search for potential line-like signals from the BH spike.Such line-like signals could be generated in the process of DM particles annihilating into double photons.We adopt the gamma-ray data from the Dark Matter Particle Explorer(DAMPE).Although the DAMPE has a much smaller effective area than the Fermi-LAT,the gamma-ray line search can benefit from its unprecedented high energy resolution.No significant line-like signals are found in our analysis.We derive upper limits on the cross section of the annihilation based on this non-detection.We find that despite the DAMPE’s small effective area for photon detection,we can still place strong constraints on the cross section(<σv>≥10^(-27)cm^(3)s^(-1))in the spike scenario due to the very bright model-expected flux from the spike.Our results indicate that either DM does not annihilate primarily through theγγchannel in the mass range we considered or no sharp density spike is present at the GC.

Widespread complex organic molecules in the Galactic center

With the support by the Major Program of the National Natural Science Foundation of China,a research group led by Prof.Shen Zhiqiang（沈志强）from Shanghai Astronomical Observatory,Chinese Academy of Sciences reports the detection of widespread CH2OHCHO（glycolaldehyde） and

A common origin of muon g-2 anomaly,Galaxy Center GeV excess and AMS-02 anti-proton excess in the NMSSM

The supersymmetric model is one of the most attractive extensions of the Standard Model of particle physics.In light of the most recently reported anomaly of the muon g-2 measurement by the FermiLab E989 experiment,and the excesses of gamma rays at the Galactic center observed by Fermi-LAT space telescope,as well as the antiproton excess observed by the Alpha Magnetic Spectrometer,we propose to account for all these anomalies or excesses in the Next-to-Minimal Supersymmetric Standard Model(NMSSM).Considering various experimental constraints including the Higgs mass,B-physics,collider data,dark matter relic density and direct detections,we find that a~60 GeV bino-like neutralino is able to successfully explain all these observations.Our scenario can be sensitively probed by future direct detection experiments.

Interpretation of the Galactic gamma-ray excess with the dark matter indicated by ^(8)Be and ^(4)He anomalous transitions

The long-standing Galactic center gamma-ray excess could be explained by GeV dark matter(DM)annihilation,but the DM interpretation seems to conflict with recent joint limits from different astronomical scale observations such as dwarf spheroidal galaxies,the Milky Way halo,and galaxy groups/clusters.Motivated by ^(8)Be and ^(4)He anomalous transitions with possible new interactions mediated by a vector boson X,we consider a small fraction of DM mainly annihilating into a pair of on-shell vector bosons followed by in this paper.The Galactic center gamma-ray excess is explained by this DM cascade annihilation.The gamma rays are mainly from inverse Compton scattering emission,and the DM cascade annihilation could be compatible with joint astrophysical limits and meanwhile be allowed by AMS-02 positron observation.The direct detection of this model is also discussed.

Phenomenology of colored radiative neutrino mass model and its implications on cosmic-ray observations

We extend the colored Zee-Babu model with a gauged U（1）B-L symmetry, and a scalar singlet dark matter （DM） candidate S. The spontaneous breaking of U（1）B-L leaves a residual Z2 symmetry that stabilizes the DM, and generates a tiny neutrino mass at the two-loop level with the color seesaw mechanism. After investigating the DM and flavor phenomenology of this model systematically, we further focus on its imprint on two cosmic-ray anomalies： The Fermi-LAT gamma-ray excess at the Galactic Center （GCE）, and the PeV ultra-high energy （UHE） neutrino events at the IceCube. We found that the Fermi-LAT GCE spectrum can be well-fitted by DM annihilation into a pair of on-shell singlet Higgs mediators while being compatible with the constraints from the relic density, direct detections, and dwarf spheroidal galaxies, in the Milky Way. Although the UHE neutrino events at the IceCube could be accounted for by the resonance production of a TeV-scale leptoquark, the relevant Yukawa couplings have been severely limited by the current low-energy flavor experiments. We subsequently derive the IceCube limits on the Yukawa couplings by employing its latest six-year data.