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 kg d. 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.
|Original language||English (US)|
|Number of pages||8|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|State||Published - Nov 30 2009|
Bibliographical noteFunding Information:
We wish to acknowledge the support of the National Sciences and Engineering Research Council of Canada (NSERC) , the Canada Foundation for Innovation (CFI) , the National Science Foundation (NSF) for funding and the Czech Ministry of Education, Youth and Sports within the project MSM6840770029 for financial support. We also thank SNOLAB and its staff for its hospitality and for providing help and competent advice whenever needed. This work is also supported by the NSF grant PHY-0856273 and the Indiana University South Bend Research and Development Committee .
- Dark matter
- Superheated droplets