• Open Access

Self-heating of strongly interacting massive particles

Ayuki Kamada, Hee Jung Kim, and Hyungjin Kim
Phys. Rev. D 98, 023509 – Published 13 July 2018

Abstract

It was recently pointed out that semiannihilating dark matter (DM) may experience a novel temperature evolution dubbed as self-heating. Exothermic semiannihilation converts the DM mass to the kinetic energy. This yields a unique DM temperature evolution, Tχ1/a, in contrast to Tχ1/a2 for free-streaming nonrelativistic particles. Self-heating continues as long as self-scattering sufficiently redistributes the energy of DM particles. In this paper, we study the evolution of cosmological perturbations in self-heating DM. We find that sub-GeV self-heating DM leaves a cutoff on the subgalactic scale of the matter power spectrum when the self-scattering cross section is σself/mχO(1)cm2/g. Then we present a particle physics realization of the self-heating DM scenario. The model is based on recently proposed strongly interacting massive particles with pionlike particles in a QCD-like sector. Pionlike particles semiannihilate into an axionlike particle, which is thermalized with dark radiation. The dark radiation temperature is smaller than the standard model temperature, evading the constraint from the effective number of neutrino degrees of freedom. It is easily realized when the dark sector is populated from the standard model sector through a small coupling.

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  • Received 24 May 2018

DOI:https://doi.org/10.1103/PhysRevD.98.023509

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

Published by the American Physical Society

Physics Subject Headings (PhySH)

Particles & FieldsGravitation, Cosmology & Astrophysics

Authors & Affiliations

Ayuki Kamada1,*, Hee Jung Kim2,†, and Hyungjin Kim3,‡

  • 1Center for Theoretical Physics of the Universe, Institute for Basic Science (IBS), Daejeon 34126, Korea
  • 2Department of Physics, KAIST, Daejeon 34141, Korea
  • 3Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 7610001, Israel

  • *akamada@ibs.re.kr
  • hyzer333@kaist.ac.kr
  • hyungjin.kim@weizmann.ac.il

Article Text

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Issue

Vol. 98, Iss. 2 — 15 July 2018

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