The gamma-ray spectral feature from Kaluza-Klein dark matter annihilation and its observability

Abstract

The theory of universal extra dimensions involves Kaluza-Klein (KK) particles. The lightest KK particle (LKP) is one of the good candidates for cold dark matter. Annihilation of LKP dark matter in the Galactic halo produces high-energy gamma-rays. The gamma-ray spectrum shows a characteristic peak structure around the LKP mass. This paper investigates the observability of this peak structure by near-future detectors taking account of their energy resolution, and calculates the expected energy spectrum of the gamma-ray signal. Then, by using the HESS data, we set some constraints on the boost factor, which is a product of the annihilation cross section relative to the thermal one and an uncertain factor dependent on the substructure of the LKP distribution in the Galactic halo, for each LKP mass. The resulting upper limit on the boost factor is in the range from 1 to 30. The constraints can be regarded as comparable with the results of previous work for gamma-ray and electron-positron observation. However, the observational data for the TeV or higher energy region are still limited, and the possible LKP signal is not conclusive. Thus, we expect near-future missions with better sensitivity will clarify whether the LKP dark matter should exist or not.

arXiv comment15 pages, 8 figures: Accepted for publication in the International Journal of Modern Physics D

References in corpus (31)

• The Structure of Cold Dark Matter Halos
• Planck 2013 results. XVI. Cosmological parameters
• Particle Dark Matter: Evidence, Candidates and Constraints
• Fermi Large Area Telescope Second Source Catalog
• Is the Lightest Kaluza-Klein Particle a Viable Dark Matter Candidate?
• Observability of Gamma Rays from Dark Matter Neutralino Annihilations in the Milky Way Halo
• Acceleration of petaelectronvolt protons in the Galactic Centre
• Probing the ATIC peak in the cosmic-ray electron spectrum with H.E.S.S
• Radiative Corrections to Kaluza-Klein Masses
• A Tentative Gamma-Ray Line from Dark Matter Annihilation at the Fermi Large Area Telescope
• The DArk Matter Particle Explorer mission
• Fermi LAT Search for Internal Bremsstrahlung Signatures from Dark Matter Annihilation
• Observations of Milky Way Dwarf Spheroidal galaxies with the Fermi-LAT detector and constraints on Dark Matter models
• Search for Gamma-ray Spectral Lines with the Fermi Large Area Telescope and Dark Matter Implications
• Fermi LAT Search for Dark Matter in Gamma-ray Lines and the Inclusive Photon Spectrum
• Gamma Ray Signals from Dark Matter: Concepts, Status and Prospects
• H.E.S.S. observations of the Galactic Center region and their possible dark matter interpretation
• Gamma Rays from Kaluza-Klein Dark Matter
• Dark Matter Candidates
• The Galactic Center as a Dark Matter Gamma-Ray Source
• Galactic center at very high-energies
• Astrophysical inputs on the SUSY dark matter annihilation detectability
• Probing Kaluza-Klein Dark Matter with Neutrino Telescopes
• Strong Evidence for Gamma-ray Line Emission from the Inner Galaxy
• Two photon annihilation of Kaluza-Klein dark matter
• Is the 130 GeV Line Real? A Search for Systematics in the Fermi-LAT Data
• Investigating Gamma-Ray Lines from Dark Matter with Future Observatories
• On the Relevance of Sharp Gamma-Ray Features for Indirect Dark Matter Searches
• Perspective of monochromatic gamma-ray line detection with the High Energy cosmic-Radiation Detection (HERD) facility onboard China's Space Station
• Dark matter origin of the gamma ray emission from the galactic center observed by HESS
• The electron plus positron spectrum from annihilation of Kaluza-Klein dark matter in the Galaxy

Cited by in corpus (3)

• Generalized geometrical coupling for vector field localization on thick brane in asymptotic Anti-de Sitter spacetime
• The maximum mass of dark matter existing in compact stars based on the self-interacting fermionic model
• Cosmological abundance of primordial black holes in mixed dark matter scenarios incorporating Kaluza-Klein dark matter