Dark matter spin-dependent limits for WIMP interactions on 19F by PICASSO

The PICASSO experiment at SNOLAB reports new results for spin-dependent WIMP interactions on 19F 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 19F of 65 g and 69 g respectively and a total exposure of 13.75±0.48 kgd. No dark matter signal was found and for WIMP masses around 24 GeV/c2 new limits have been obtained on the spin-dependent cross section on 19F of σF=13.9 pb (90% C.L.) which can be converted into cross section limits on protons and neutrons of σp=0.16 pb and σn=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.