Dark Matter Search at Boulby Mine

Abstract

The Boulby Dark Matter Collaboration is running a WIMP Dark Matter research programme in the underground laboratory of Boulby Mine for over a decade. Results have been reported previously from the NaIAD detector array -using scintillation properties in NaI crystals [4,5,6]. Currently, the programme is based on (1) liquid Xenon (LXe) as the WIMP target and (2) directional detection in low pressure gas detectors (Drift, reported at this conference [3]). This contribution concentrates on Zeplin-1, the LXe first project: a 3.1kg of LXe scintillation detector with a background discrimination based on Pulse Shape Analysis. The current status of the experiment is shown and first limits on nuclear recoil events are reported. Setups with improved background discrimination tools are commissioned: Zeplin-2 and Zeplin-3 will be installed underground early 2004. Progress are reported in another contribution to this conference [1]. These are important steps towards the design of a ton-scale LXe Dark Matter detector array (reported in [2]).

WMAP constraints on SUGRA models with non-universal gaugino masses and prospects for direct detection

“…In fact, the first results from CDMS2 have been published recently [36] showing already significant improvement on the upper limit. Finally ton-scale detectors are also planned, such as ZeplinIV [37], Genius [38] and Xenon [39]. These large scale detector will reach a sensitivity between 10 −9 − 10 −10 pb for neutralinos around 100GeV.…”

“…CDMS2 has recently published much improved upper limits [36]. By the time one reaches ton-size detectors, such as ZeplinIV [37], Genius [38] and Xenon [39] a signal could be found for a significant fraction of the parameter space of the mSUGRA model. At the same time many detectors that are mostly sensitive to the spin dependent part of the neutralino nucleon cross section have started taking data, for example Naiad [40], Simple [41] and PICASSO [42].…”

Cryogenic dark matter searches

“…The limiting factors are systematic errors which may be reduced by dedicated calibration runs. Probably due to the difficulties and ambiguities of these runs, the limits given by ZEPLIN I [9] are still labeled preliminary. Future liquid xenon experiments are ZEPLIN II and ZEPLIN III [10], potentially leading to ZEPLIN-MAX.…”

First results with the ORPHEUS dark matter detector

“…11. Exclusion plots from several other experiments [26,27,28,29,30,31] (labeled lines) are also shown in the figure together with the 3σ annual modulation region, claimed by the DAMA group [32] (grey area). In the constrained minimal supersymmetric extension of the standard model [33], the spin-independent neutralino cross sections lie more than 2 orders of magnitude below the sensitivity of actual experiments.…”