Search for inelastic dark matter-nucleus scattering with the PICO-60 CF$_{3}$I and C$_{3}$F$_{8}$ bubble chambers

TL;DR

This paper reports a search for inelastic dark matter-nucleus interactions using PICO-60 bubble chambers with CF$_{3}$I and C$_{3}$F$_{8}$, setting limits on dark matter models and challenging some explanations of DAMA signals.

Contribution

First search for inelastic dark matter scattering with PICO-60 chambers using iodine and fluorine targets, providing new constraints on dark matter properties.

Findings

Disfavors certain inelastic dark matter models explaining DAMA.

Sets new limits on dark matter-nucleus interaction cross sections.

Demonstrates the sensitivity of bubble chambers to inelastic scattering.

Abstract

PICO bubble chambers have exceptional sensitivity to inelastic dark matter-nucleus interactions due to a combination of their extended nuclear recoil energy detection window from a few keV to $O$(100 keV) or more and the use of iodine as a heavy target. Inelastic dark matter-nucleus scattering is interesting for studying the properties of dark matter, where many theoretical scenarios have been developed. This study reports the results of a search for dark matter inelastic scattering with the PICO-60 bubble chambers. The analysis reported here comprises physics runs from PICO-60 bubble chambers using CF$_{3}$I and C$_{3}$F$_{8}$. The CF$_{3}$I run consisted of 36.8 kg of CF$_{3}$I reaching an exposure of 3415 kg-day operating at thermodynamic thresholds between 7 and 20 keV. The C$_{3}$F$_{8}$ runs consisted of 52 kg of C$_{3}$F$_{8}$ reaching exposures of 1404 kg-day and 1167 kg-day running at thermodynamic thresholds of 2.45 keV and 3.29 keV, respectively. The analysis disfavors various scenarios, in a wide region of parameter space, that provide a feasible explanation of the signal observed by DAMA, assuming an inelastic interaction, considering that the PICO CF$_{3}$I bubble chamber used iodine as the target material.