Exothermic isospin-violating dark matter after SuperCDMS and CDEX

TL;DR

This paper demonstrates that combining exothermic scattering with isospin violation can reconcile certain dark matter detection results, requiring a new gauge boson to facilitate interactions.

Contribution

It introduces a model of exothermic isospin-violating dark matter that explains experimental tensions and proposes a new gauge boson for interaction mediation.

Findings

Exothermic IVDM can reconcile CDMS-Si with other null results.

Tension persists with CoGeNT data despite the model.

A new vector gauge boson is necessary for such dark matter interactions.

Abstract

We show that exothermic isospin-violating dark matter (IVDM) can make the results of the latest CDMS-Si experiment consistent with recent null experiments, such as XENON10, XENON100, LUX, CDEX, and SuperCDMS, whereas for the CoGeNT experiment, a strong tension still persists. For CDMS-Si, separate exothermic dark matter or isospin-violating dark matter cannot fully ameliorate the tensions among these experiments; the tension disappears only if exothermic scattering is combined with an isospin-violating effect of f_n/f_p=-0.7. For such exothermic IVDM to exist, at least a new vector gauge boson (dark photon or dark Z') that connects SM quarks to Majorana-type DM particles is required.