Gamma-Ray Effects of Dark Forces in Dark Matter Clumps

Existence of new gauge U(1) symmetry possessed by dark matter (DM) particles implies the existence of a new Coulomb-like interaction, which leads to Sommerfeld-Gamow-Sakharov enhancement of dark matter annihilation at low relative velocities. We discuss a possibility to put constraints on such dark forces of dark matter from the observational data on the gamma radiation in our Galaxy. Gamma-rays are supposed to originate from annihilation of DM particles in the small scale clumps, in which annihilation rate is supposed to be enhanced, besides higher density, due to smaller relative velocitiesvof DM particles. For possible cross sections, mass of annihilating particles, masses of clumps, and the contribution of annihilating particles in the total DM density we constrain the strength of new dark long range forces from comparison of predicted gamma-ray signal with Fermi/LAT data on unidentified point-like gamma-ray sources (PGS) as well as on diffuseγ-radiation. Both data on diffuse radiation and data on PGS put lower constraints on annihilation cross section at any dark interaction constant, where diffuse radiation provides stronger constraint at smaller clump mass. Density of annihilating DM particles is conventionally supposed to be defined by the frozen annihilation processes in early Universe.

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Bounds on cross sections and lifetimes for dark matter annihilation and decay into charged leptons from gamma-ray observations of dwarf galaxies

Physical Review D ◽

10.1103/physrevd.80.023506 ◽

2009 ◽

Vol 80 (2) ◽

Cited By ~ 88

Author(s):

Rouven Essig ◽

Neelima Sehgal ◽

Louis E. Strigari

Keyword(s):

Dark Matter ◽

Cross Sections ◽

Gamma Ray ◽

Dwarf Galaxies ◽

Dark Matter Annihilation ◽

Charged Leptons

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Constraints on the primordial power spectrum of small scales using the neutrino signals from the dark matter decay

International Journal of Modern Physics A ◽

10.1142/s0217751x14501942 ◽

2014 ◽

Vol 29 (32) ◽

pp. 1450194 ◽

Cited By ~ 6

Author(s):

Yupeng Yang

Keyword(s):

Dark Matter ◽

Power Spectrum ◽

Large Scale ◽

Gamma Ray ◽

Neutrino Flux ◽

Small Scale ◽

Scale Invariant ◽

Dark Matter Annihilation ◽

Primordial Power Spectrum ◽

Small Scales

Many inflation theories predict that the primordial power spectrum is scale invariant. The amplitude of the power spectrum can be constrained by different observations such as the cosmic microwave background (CMB), Lyman-α, large-scale structures and primordial black holes (PBHs). Although the constraints from the CMB are robust, the corresponding scales are very large (10-4 < k < 1 Mpc -1). For small scales (k > 1 Mpc -1), the research on the PBHs provides much weaker limits. Recently, ultracompact dark matter minihalos (UCMHs) was proposed and it was found that they could be used to constraint the small-scale primordial power spectrum. The limits obtained by the research on the UCMHs are much better than that of PBHs. Most of previous works focus on the dark matter annihilation within the UCMHs, but if the dark matter particles do not annihilate the decay is another important issue. In previous work [Y.-P. Yang, G.-L. Yang and H.-S. Zong, Europhys. Lett.101, 69001 (2013)], we investigated the gamma-ray flux from the UCMHs due to the dark matter decay. In addition to these flux, the neutrinos are usually produced going with the gamma-ray photons especially for the lepton channels. In this work, we studied the neutrino flux from the UCMHs due to the dark matter decay. Finally, we got the constraints on the amplitude of primordial power spectrum of small scales.

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