Self-interacting inelastic dark matter in the light of XENON1T excess

Manoranjan Dutta,Debasish Borah,Narendra Sahu,Satyabrata Mahapatra

doi:10.1103/physrevd.103.095018

Abstract

We propose a self-interacting inelastic dark matter (DM) scenario as a possible origin of the recently reported excess of electron recoil events by the XENON1T experiment. Two quasi-degenerate Majorana fermion DM interact within themselves via a light hidden sector massive gauge boson and with the standard model particles via gauge kinetic mixing. We also consider an additional long-lived singlet scalar which helps in realising correct dark matter relic abundance via a hybrid setup comprising of both freeze-in and freeze-out mechanisms. While being consistent with the required DM phenomenology along with sufficient self-interactions to address the small scale issues of cold dark matter, the model with GeV scale DM can explain the XENON1T excess via inelastic down scattering of heavier DM component into the lighter one. All these requirements leave a very tiny parameter space keeping the model very predictive for near future experiments.

Highlights

There exists a convincing amount of evidence suggesting the presence of a nonluminous, nonbaryonic form of matter in the present Universe, popularly known as dark matter (DM)
We propose a self-interacting inelastic dark matter (DM) scenario as a possible origin of the recently reported excess of electron recoil events by the XENON1T experiment
While being consistent with the required DM phenomenology along with sufficient self-interactions to address the small-scale issues of cold dark matter, the model with GeV-scale DM can explain the XENON1T excess via inelastic down-scattering of the heavier DM component into the lighter one

Summary

INTRODUCTION

There exists a convincing amount of evidence suggesting the presence of a nonluminous, nonbaryonic form of matter in the present Universe, popularly known as dark matter (DM). While SIDM solves the problems at small scales, it reproduces the CDM halos at large radii, consistent with observations This is due to the fact that the self-interacting scattering rate is proportional to DM density. The scalar field which leads to spontaneous breaking of dark sector gauge symmetry induces a tiny Majorana mass to a singlet Dirac fermion field, leading to an inelastic DM scenario [55,56]. In this setup, we first find the DM parameter space consistent with velocity-dependent self-interaction rates explaining the data at the scale of clusters, galaxies, and dwarf galaxies. While we stick to such minimal DM models in this work, such Abelian gauge extensions can be motivated from other phenomena like the origin of light neutrino masses as well, as discussed in several works including Refs. [40,57,58,59,60,61,62,63,64,65,66,67]

DARK MATTER SELF-INTERACTION

DARK MATTER PRODUCTION

XENON1T EXCESS

CONCLUSION

Findings

DM velocity distribution function