Silicon detector dark matter results from the final exposure of CDMS II

R Agnese; Z Ahmed; A J Anderson; S Arrenberg; D Balakishiyeva; R Basu Thakur; D A Bauer; J Billard; A Borgland; D Brandt; P L Brink; T Bruch; R Bunker; B Cabrera; D O Caldwell; D G Cerdeno; H Chagani; J Cooley; B Cornell; C H Crewdson; P Cushman; M Daal; F Dejongh; E do Couto e Silva; T Doughty; L Esteban; S Fallows; E Figueroa-Feliciano; J Filippini; J Fox; M Fritts; G L Godfrey; S R Golwala; J Hall; R H Harris; S A Hertel; T Hofer; D Holmgren; L Hsu; M E Huber; A Jastram; O Kamaev; B Kara; M H Kelsey; A Kennedy; P Kim; M Kiveni; K Koch; M Kos; S W Leman; B Loer; E Lopez Asamar; R Mahapatra; V Mandic; C Martinez; K A McCarthy; N Mirabolfathi; R A Moffatt; D C Moore; P Nadeau; R H Nelson; K Page; R Partridge; M Pepin; A Phipps; K Prasad; M Pyle; H Qiu; W Rau; P Redl; A Reisetter; Y Ricci; T Saab; B Sadoulet; J Sander; K Schneck; R W Schnee; S Scorza; B Serfass; B Shank; D Speller; K M Sundqvist; A N Villano; B Welliver; D H Wright; S Yellin; J J Yen; J Yoo; B A Young; J Zhang; CDMS Collaboration

doi:10.1103/PhysRevLett.111.251301

Silicon detector dark matter results from the final exposure of CDMS II

Phys Rev Lett. 2013 Dec 20;111(25):251301. doi: 10.1103/PhysRevLett.111.251301. Epub 2013 Dec 16.

Authors

R Agnese¹, Z Ahmed², A J Anderson³, S Arrenberg⁴, D Balakishiyeva¹, R Basu Thakur⁵, D A Bauer⁵, J Billard³, A Borgland⁶, D Brandt⁶, P L Brink⁶, T Bruch⁴, R Bunker⁷, B Cabrera⁸, D O Caldwell⁹, D G Cerdeno¹⁰, H Chagani¹¹, J Cooley¹², B Cornell², C H Crewdson¹³, P Cushman¹¹, M Daal¹⁴, F Dejongh⁵, E do Couto e Silva⁶, T Doughty¹⁴, L Esteban¹⁰, S Fallows¹¹, E Figueroa-Feliciano³, J Filippini², J Fox¹³, M Fritts¹¹, G L Godfrey⁶, S R Golwala², J Hall¹⁵, R H Harris¹⁶, S A Hertel³, T Hofer¹¹, D Holmgren⁵, L Hsu⁵, M E Huber¹⁷, A Jastram¹⁶, O Kamaev¹³, B Kara¹², M H Kelsey⁶, A Kennedy¹¹, P Kim⁶, M Kiveni⁷, K Koch¹¹, M Kos⁷, S W Leman³, B Loer⁵, E Lopez Asamar¹⁰, R Mahapatra¹⁶, V Mandic¹¹, C Martinez¹³, K A McCarthy³, N Mirabolfathi¹⁴, R A Moffatt⁸, D C Moore², P Nadeau¹³, R H Nelson², K Page¹³, R Partridge⁶, M Pepin¹¹, A Phipps¹⁴, K Prasad¹⁶, M Pyle¹⁴, H Qiu¹², W Rau¹³, P Redl⁸, A Reisetter¹⁸, Y Ricci¹³, T Saab¹, B Sadoulet¹⁹, J Sander¹⁶, K Schneck⁶, R W Schnee⁷, S Scorza¹², B Serfass¹⁴, B Shank⁸, D Speller¹⁴, K M Sundqvist¹⁴, A N Villano¹¹, B Welliver¹, D H Wright⁶, S Yellin⁸, J J Yen⁸, J Yoo⁵, B A Young²⁰, J Zhang¹¹; CDMS Collaboration

Affiliations

¹ Department of Physics, University of Florida, Gainesville, Florida 32611, USA.
² Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, California 91125, USA.
³ Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
⁴ Physics Institute, University of Zürich, Winterthurerstrasse 190, CH-8057, Switzerland.
⁵ Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA.
⁶ SLAC National Accelerator Laboratory/Kavli Institute for Particle Astrophysics and Cosmology, Menlo Park, California 94025, USA.
⁷ Department of Physics, Syracuse University, Syracuse, New York 13244, USA.
⁸ Department of Physics, Stanford University, Stanford, California 94305, USA.
⁹ Department of Physics, University of California, Santa Barbara, California 93106, USA.
¹⁰ Departamento de Física Teórica and Instituto de Física Teórica UAM/CSIC, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
¹¹ School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA.
¹² Department of Physics, Southern Methodist University, Dallas, Texas 75275, USA.
¹³ Department of Physics, Queen's University, Kingston, Ontario K7L 3N6, Canada.
¹⁴ Department of Physics, University of California, Berkeley, California 94720, USA.
¹⁵ Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
¹⁶ Department of Physics, Texas A&M University, College Station, Texas 77843, USA.
¹⁷ Department of Physics, University of Colorado, Denver, Colorado 80217, USA.
¹⁸ Department of Physics, University of Evansville, Evansville, Indiana 47722, USA.
¹⁹ Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA and Department of Physics, University of California, Berkeley, California 94720, USA.
²⁰ Department of Physics, Santa Clara University, Santa Clara, California 95053, USA.

PMID: 24483735
DOI: 10.1103/PhysRevLett.111.251301

Abstract

We report results of a search for weakly interacting massive particles (WIMPS) with the silicon detectors of the CDMS II experiment. This blind analysis of 140.2 kg day of data taken between July 2007 and September 2008 revealed three WIMP-candidate events with a surface-event background estimate of 0.41(-0.08)(+0.20)(stat)(-0.24)(+0.28)(syst). Other known backgrounds from neutrons and 206Pb are limited to <0.13 and <0.08 events at the 90% confidence level, respectively. The exposure of this analysis is equivalent to 23.4 kg day for a recoil energy range of 7-100 keV for a WIMP of mass 10 GeV/c2. The probability that the known backgrounds would produce three or more events in the signal region is 5.4%. A profile likelihood ratio test of the three events that includes the measured recoil energies gives a 0.19% probability for the known-background-only hypothesis when tested against the alternative WIMP+background hypothesis. The highest likelihood occurs for a WIMP mass of 8.6 GeV/c2 and WIMP-nucleon cross section of 1.9×10(-41) cm2.