Results from the Cryogenic Dark Matter Search experiment

Abstract

The Cryogenic Dark Matter Search experiment uses low-temperature solid-state detectors to seek Weakly Interacting Massive Particles (WIMPs) and has the world's best exclusion limit on the spin-independent WIMP-nucleon cross section. The experiment uses ionization and athermal phonon signals from particle interactions to discriminate between candidate (nuclear recoil) and background (electron recoil) events with extremely high efficiency. The detectors' low energy threshold for electron recoil events allows us to perform the search for relic axions and solar axions which can interact in the detector via the axio-electric coupling $g_{a\bar{e}e}$ and the Primakoff coupling $g_{a\gamma\gamma}$ respectively. We describe the experiment and our most recent results from the Soudan 5-tower data runs which include a world-leading upper limit on the WIMP-nucleon spin-independent cross section with a minimum of $4.6\times10^{-44}$ cm$^{2}$ at the 90% confidence level (CL) for a 60 GeV/c$^{2}$ WIMP, the world-leading experimental upper limit on the axio-electric coupling of $1.4\times10^{-12}$ at the 90% CL for a 2.5 keV/c$^{2}$ axion, and the upper limit on the axion-photon coupling of $2.4\times10^{-9}$ GeV$^{-1}$ at the 95% CL.