Dark Matter Spin-Dependent Limits for WIMP Interactions on 19-F by PICASSO

TL;DR

The PICASSO experiment sets new limits on spin-dependent WIMP interactions with fluorine using advanced superheated droplet detectors, constraining dark matter models and challenging recent interpretations of DAMA/LIBRA signals.

Contribution

Introduction of a new detector generation with background discrimination capabilities for spin-dependent WIMP searches on $^{19}$F.

Findings

No dark matter signal detected in the dataset.

Established new upper limits on WIMP cross sections for fluorine.

Constraints challenge interpretations of DAMA/LIBRA annual modulation.

Abstract

The PICASSO experiment at SNOLAB reports new results for spin-dependent WIMP interactions on $^{19}$F using the superheated droplet technique. A new generation of detectors and new features which enable background discrimination via the rejection of non-particle induced events are described. First results are presented for a subset of two detectors with target masses of $^{19}$F of 65 g and 69 g respectively and a total exposure of 13.75 $\pm$ 0.48 kgd. No dark matter signal was found and for WIMP masses around 24 GeV/c$^2$ new limits have been obtained on the spin-dependent cross section on $^{19}$F of $\sigma_F$ = 13.9 pb (90% C.L.) which can be converted into cross section limits on protons and neutrons of $\sigma_p$ = 0.16 pb and $\sigma_n$ = 2.60 pb respectively (90% C.L). The obtained limits on protons restrict recent interpretations of the DAMA/LIBRA annual modulations in terms of spin-dependent interactions.