Pico-charged intermediate particles rescue dark matter interpretation of 511 keV signal

Abstract

Various alleged indirect dark matter search signals, such as the 511 keV line from galaxy center or the PAMELA/AMS02 signal, are often challenged by the absence of corresponding signal from dwarf galaxies and/or by the absence of an impact on CMB through delayed recombination. We propose a novel scenario that can avoid these bounds based on the decay of dark matter, X, to a pair of intermediate particles C andC with a lifetime much greater than the age of universe. The annihilation of these intermediate particles eventually leads to a dark matter signal. The bounds from CMB can be easily avoided by the fact that at the time of recombination, not enough C particles had been accumulated. In order to keep C particles from leaving the galaxy, we assume the particles have a small electric charge so in the galactic disk, the magnetic field keeps the C particles in the vicinity of their production. However, they can escape the dwarf galaxies and the dark matter halo where the magnetic field is weak, leading to null signal from these regions. The small charge can have interesting consequences including a signal in direct dark matter search experiments.

Neutrino and Positron Constraints on Spinning Primordial Black Hole Dark Matter

“…The origin of the 511 keV gamma-ray line from the Galactic Center (GC) is one of the enduring mysteries of astrophysics [68][69][70][71]. Many models have been proposed to explain this observation [72][73][74][75][76][77][78][79][80], yet none are confirmed. Our constraints are agnostic of these models and robust.…”

Neutrino and Positron Constraints on Spinning Primordial Black Hole Dark Matter

“…The origin of the 511 keV gamma-ray line from the Galactic centre (GC) is one of the enduring mysteries of astrophysics [89][90][91][92]. Many models have been proposed to explain this observation [93][94][95][96][97][98][99][100][101][102][103][104], yet none are confirmed. Our constraints are agnostic of these models and robust.…”

Millicharged particles from the heavens: single- and multiple-scattering signatures

“…We make a standard assumption regarding the nature of this new millicharged particle -that it has some mass and small coupling to the Standard Model photon via a small electric charge. It is possible that a particle of such nature constitutes some fraction of the Dark Matter in the universe, or even an intermediate state in which Dark Matter can decay [35][36][37]. In the former case, a number of additional constraints apply.…”