New Constraints on Millicharged Particles from Cosmic-ray Production

Abstract

We study the production of exotic millicharged particles (MCPs) from cosmic ray-atmosphere collisions, which constitutes a permanent MCP production source for all terrestrial experiments. Our calculation of the MCP flux can be used to reinterpret existing limits from experiments such as MACRO and Majorana on an ambient flux of ionizing particles. Large-scale underground neutrino detectors are particularly favorable targets for the resulting MCPs. Using available data from the Super-K experiment, we set new limits on MCPs, which are the best in sensitivity reach for the mass range 0.1 mχ 0.5 GeV, and which are competitive with accelerator-based searches for masses up to 1.5 GeV. Applying these constraints to models where a sub-dominant component of dark matter (DM) is fractionally charged allows us to probe parts of the parameter space that are challenging for conventional direct-detection DM experiments, independently of any assumptions about the DM abundance. These results can be further improved with the next generation of large-scale neutrino detectors.

Charged Black Hole Mergers: Orbit Circularisation and Chirp Mass Bias

“…One of such scenarios is a class of self-interacting Dark Matter (DM) models where the interaction is mediated by some dark photon (see e.g. [24,25,26] for similar motivations to consider charged BHs). After all, all the interactions in the standard model of particles (leaving gravity aside) are mediated by massless spin-1 gauge bosons and, after symmetry breaking, the photon remains as the relevant one on large (as compared to the corresponding Compton wavelengths) scales, so it is plausible that the dark sector could also contain some dark U(1) gauge field.…”

Millicharged Cosmic Rays and Low Recoil Detectors

“…As has been recently demonstrated in [33], cosmic rays can efficiently produce mCPs in the upper atmosphere. We consider the sensitivity of XENON1T to this production channel, but also consider a secondary flux component stemming from the ISM.…”

“…We consider the sensitivity of XENON1T to this production channel, but also consider a secondary flux component stemming from the ISM. Much of the methodology used in this paper is outlined in detail in [33] and so we discuss only the most important details here and refer the interested reader to our earlier work.…”

“…(a) The mCPs do not constitute a component of the dark matter, but are readily produced via collisions of cosmic rays with the interstellar medium (ISM) in addition to local cosmic-rays' collisions with the upper atmosphere (as discussed in [33]).…”

“…As we show below, such low thresholds are especially advantageous for Scenario (b). A natural question, then, is whether or not XENON1T's unique low-threshold capabilities are able to overcome the large discrepancies in fiducial volume between itself and Super-Kamiokande (1 t vs 22.5 kt), which has recently been identified as a resource for studying mCPs from cosmic rays [33].…”