Constraint on ghost-free bigravity from gravitational Cherenkov radiation

Rampei Kimura, Takahiro Tanaka, Kazuhiro Yamamoto, Yasuho Yamashita

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

We investigate gravitational Cherenkov radiation in a healthy branch of background solutions in the ghost-free bigravity model. In this model, because of the modification of dispersion relations, each polarization mode can possess subluminal phase velocities, and the gravitational Cherenkov radiation could be potentially emitted from a relativistic particle. In the present paper, we derive conditions for the process of the gravitational Cherenkov radiation to occur and estimate the energy emission rate for each polarization mode. We found that the gravitational Cherenkov radiation emitted even from an ultrahigh energy cosmic ray is sufficiently suppressed for the graviton's effective mass less than 100 eV, and the bigravity model with dark matter coupled to the hidden metric is therefore consistent with observations of high energy cosmic rays.

Original languageEnglish
Article number064059
JournalPhysical Review D
Volume94
Issue number6
DOIs
Publication statusPublished - Sep 21 2016

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

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