Cosmic-ray knee and diffuse gamma, e+ and pbar fluxes from collisions of cosmic rays with dark matter

Abstract

In models with extra dimensions the fundamental scale of gravity M_D could be of order TeV. In that case the interaction cross section between a cosmic proton of energy E and a dark matter particle χwill grow fast with E for center of mass energies \sqrt{2m_χE} above M_D, and it could reach 1 mbarn at E\approx 10^9 GeV. We show that these gravity-mediated processes would break the proton and produce a diffuse flux of particles/antiparticles, while boosting χwith a fraction of the initial proton energy. We find that the expected cross sections and dark matter densities are not enough to produce an observable asymmetry in the flux of the most energetic (extragalactic) cosmic rays. However, we propose that unsuppressed TeV interactions may be the origin of the knee observed in the spectrum of galactic cosmic rays. The knee would appear at the energy threshold for the interaction of dark matter particles with cosmic protons trapped in the galaxy by \muG magnetic fields, and it would imply a well defined flux of secondary antiparticles and TeV gamma rays.

19 pages, references added, version to appear in JCAP

References in corpus (5)

• TeV Gamma-Ray Sources from a Survey of the Galactic Plane with Milagro
• New Gamma-Ray Contributions to Supersymmetric Dark Matter Annihilation
• Diffuse Gamma Rays from the Galactic Plane: Probing the "GeV Excess" and Identifying the "TeV Excess"
• Constraints on the TeV source population and its contribution to the galactic diffuse TeV emission
• Hawking evaporation of cosmogenic black holes in TeV-gravity models

Cited by in corpus (8)

• Phenomenology of $U(1{)}_{L_{\mu }-L_{\tau }}$ charged dark matter at PAMELA/FERMI and colliders
• Double-action dark matter, PAMELA and ATIC
• Constraining the regular Galactic Magnetic Field with the 5-year WMAP polarization measurements at 22 GHz
• Cosmic Ray-Dark Matter Scattering: a New Signature of (Asymmetric) Dark Matter in the Gamma Ray Sky
• Black hole gas in the early universe
• Cosmic ray knee and new physics at the TeV scale
• New physics, the cosmic ray spectrum knee, and $pp$ cross section measurements
• Expectation on probing the origin of the cosmic ray knee with the LHAASO experiment