Massive hidden photons as lukewarm dark matter

Abstract

We study the possibility that a keV-MeV mass hidden photon (HP), i.e. a hidden sector U(1) gauge boson, accounts for the observed amount of dark matter. We focus on the case where the HP interacts with the standard model sector only through kinetic mixing with the photon. The relic abundance is computed including all relevant plasma effects into the photon's self-energy, which leads to a resonant yield almost independent of the HP mass. The HP can decay into three photons. Moreover, if light enough it can be copiously produced in stars. Including bounds from cosmic photon backgrounds and stellar evolution, we find that the hidden photon can only give a subdominant contribution to the dark matter. This negative conclusion may be avoided if another production mechanism besides kinetic mixing is operative.

Cosmological constraints on very dark photons

“…Although this is not justified parametrically, numerically the FD→MB substitution is quite accurate, because as it turns out the peak in the production rate (relative to entropy) is at T < m V [4].…”

“…π − + 4 He → T + n. Prior to the end of the deuterium bottleneck at T 100 keV only the former reactions are possible. They change the n/p ratio that determines the primordial 4 He value. Later, once elements have formed, charge exchange creates "extra neutrons" on top of the residual and declining neutron abundance.…”

“…Given that BBN can be sensitive to an energy release as low as O(MeV) per baryon, and that the CMB anisotropy spectrum allows us to probe sub-eV energy injection, we reach the conclusion that the early Universe can be an effective probe of VDP! The cosmological signatures of the decaying VDP were partially explored in [4,5], but to our knowledge the CMB constraints on this model were not previously studied.…”

Solar constraints on hidden photons re-visited

“…The analogous relic density of transverse HPs is [8] f T (k c ) ≈ χ 2 π j(T ) They feature an almost thermal spectrum and are produced resonantly when ω P = m, i.e., almost simultaneously with L-modes. The abundance involves the evaluation of H, T, j at the same moment as L-modes so we can express our results as a ratio of densities,…”

New Limits on Bosonic Dark Matter, Solar Axions, Pauli Exclusion Principle Violation, and Electron Decay from the Majorana Demonstrator

“…axionlike) and vector DM, with mass scale of 1-100 keV, offer an explanation for the observed subgalactic structure in the Universe, assuming a large number density compensates for their light mass. With suitable electronic coupling strength, they may be detectable via a pseudoscalar or vector-electric effect that is analogous to photoelectric absorption [12][13][14]. In addition, we report limits on the coupling of 14.4 keV solar axions competing in the M 1 transition of 57 Fe nuclei, Pauli exclusion principle violating (PEPV) electronic transitions, and electron decay, e − → invisible.…”