Departmental Colloquium

Search for dark matter with PICASSO Project in SNO lab

Ms. Marie Di Marco
Department of Physics, Université de Montréal and Sudbury NeutrinoObservatory

Time
Wed. October 29, 2003     1:30 PM     Stirling A

Abstract

The search for dark matter (DM) arouses great interest in the physics community, as it is expected to make up for 70-90\% of the total gravitational mass of the Universe. The presence of neutralinos in halos around galaxies could solve the DM problem and also support the SuperSymmetric (SUSY) extension of the Standard Model. The daily interactionrate of neutralinos with normal matter is predicted to be less than oneevent per kilogram, making their detection quite challenging. Hence DMdetectors are required to have extremely low intrinsic background and tobe scalable to large fiducial volumes. The PICASSO Project addresses these requirements by exploiting the detection principle of the bubble chamber,with the great advantage of being blind to ambient radiation. In the recent year, substantial progress in detector fabrication, purification of materials and reduction of the radon-induced background, using techniques developed at SNO, resulted in the deployment of a small scale PICASSO DM experiment in the underground laboratory of SNO. An array of 6 detectorshas been calibrated and is running steadily since July 2002. The data may lead to an improved limit on spin-dependent neutralino cross-section.

Refreshments will be available after the talk

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