Limits on Spin-Independent Interactions of Weakly Interacting Massive Particles with Nucleons from the Two-Tower Run of the Cryogenic Dark Matter Search

Abstract

We report new results from the Cryogenic Dark Matter Search (CDMS II) at the Soudan Underground Laboratory. Two towers, each consisting of six detectors, were operated for 74.5 live days, giving spectrum-weighted exposures of 34 (12) kg d for the Ge (Si) targets after cuts, averaged over recoil energies 10 -100 keV for a weakly interacting massive particle (WIMP) mass of 60 GeV=c 2 . A blind analysis was conducted, incorporating improved techniques for rejecting surface events. No WIMP signal exceeding expected backgrounds was observed. When combined with our previous results from Soudan, the 90% C.L. upper limit on the spin-independent WIMP-nucleon cross section is 1:6 10 ÿ43 cm 2 from Ge and 3 10 ÿ42 cm 2 from Si, for a WIMP mass of 60 GeV=c 2 . The combined limit from Ge (Si) is a factor of 2.5 (10) lower than our previous results and constrains predictions of supersymmetric models.

Light dark matter in the NMSSM: upper bounds on direct detection cross sections

“…All in all one finds 8) which shows that the largest values of σ SI are obtained for a large product N 11 N 13 , large tan β and low values of m H . The dominant contribution to the spin-dependent LSP-nucleon cross section σ SD originates, as in the MSSM, from Z-exchange.…”

“…We choose M A as an input parameter of the NMSSM (instead of Also shown in figure 2 are the regions compatible with the excesses of events reported by DAMA [1] (without channeling (dark blue) and with channeling (light blue)), CoGeNT [2] (light green) and a fit to the two events observed by CDMS-II [61] (denoted as CDMS-09 fit surrounded in dashed green; these events are also compatible with background). Exclusion limits are shown from Xenon10 [5] (violet), Xenon100 [7] (black) and CDMS-II [3,8] (magenta, assuming that the two observed events originate from background). • It seems difficult to explain the excesses of events reported by DAMA and CoGeNT within the general NMSSM (without unification constraints on M 1 ).…”

A Brief Review on WIMPs in 331 Electroweak Gauge Models

“…Finally, current direct detection experiments have reported no convincing WIMP signature (Bernabei et al, 2008;Ahmed et al, 2010;Aalseth et al, 2011), putting bounds on the maximum WIMP-nucleon scattering cross section (Ahmed et al, 2010;Akerib et al, 2006;Aprile et al, 2011;Akerib et al, 2014). Thus, besides building a model that yields a WIMP that does not overpopulate the Universe, considering the upper bound in Equation (23), it is imperative that the parameters producing the appropriate thermal averaged WIMP annihilation cross section also comply with the upper bounds from detection experiments.…”

“…The model was tested under the light of WMAP-3 year run results (Yao, 2006), concerning the relic CDM abundance and direct detection experiments, CDMS (2004+2005) and XENON10 (Akerib et al, 2006), besides some projected experiments (Aprile et al, 2011;Schnee et al, 2005;Aprile et al, 2005). The analysis was rather crude, since several of the parameters of the model were fixed instead of using a scan (This drawback was to be fixed only later in a study of the 331LHN model (Cogollo et al, 2014).…”

The CDMS II Data Acquisition System

“…Direct detection of this WIMP 'wind' would confirm indirect evidence of dark matter from astrophysical observations. The CDMS II [1][2][3] configuration of 30 germanium and silicon detectors ran at the Soudan Underground Lab in northern Minnesota until 2009, now replaced with the SuperCDMS detectors. Particle interactions in each 7.6 cm diameter by 1 cm thick crystal deposit energy via both ionization and phonon production.…”