Improved spin-dependent limits from the PICASSO dark matter search experiment

• Published in: Physics letters. B Vol. 624; no. 3-4; pp. 186 - 194
• Main Authors: Barnabé-Heider, M., Di Marco, M., Doane, P., Genest, M.-H., Gornea, R., Guénette, R., Leroy, C., Lessard, L., Martin, J.-P., Wichoski, U., Zacek, V., Clark, K., Krauss, C., Noble, A., Behnke, E., Feighery, W., Levine, I., Muthusi, C., Kanagalingam, S., Noulty, R.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 29.09.2005; Elsevier Science
• Subjects: Exact sciences and technology; Nuclear physics; Physics; The physics of elementary particles and fields; Protons; Weak interactions; Dark matter; Cold dark matter; Sudbury neutrino observatory; Neutrons; Massive particle; Droplets; Cross sections
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/j.physletb.2005.08.021

The PICASSO experiment reports an improved limit for the existence of cold dark matter WIMPs interacting via spin-dependent interactions with nuclei. The experiment is installed in the Sudbury Neutrino Observatory at a depth of 2070 m. With superheated C4F10 droplets as the active material, and an exposure of 1.98±0.19 kg day, no evidence for a WIMP signal was found. For a WIMP mass of 29 GeV/c2, limits on the spin-dependent cross section on protons of σp=1.31 pb and on neutrons of σn=21.5 pb have been obtained at 90% C.L. In both cases, some new parameter space in the region of WIMP masses below 20 GeV/c2 has now been ruled out. The results of these measurements are also presented in terms of limits on the effective WIMP-proton and neutron coupling strengths ap and an.