Light dark matter constraints from SuperCDMS HVeV detectors operated underground with an anticoincidence event selection

Abstract

This article presents constraints on dark-matter-electron interactions obtained from the first underground data-taking campaign with multiple SuperCDMS HVeV detectors operated in the same housing. An exposure of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mn>7.63</a:mn><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi mathvariant="normal">g</a:mi><a:mtext>−</a:mtext><a:mi>days</a:mi></a:mrow></a:math> is used to set upper limits on the dark-matter-electron scattering cross section for dark matter masses between 0.5 and <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"><d:mn>1000</d:mn><d:mtext> </d:mtext><d:mtext> </d:mtext><d:mi>MeV</d:mi><d:mo>/</d:mo><d:msup><d:mi>c</d:mi><d:mn>2</d:mn></d:msup></d:math>, as well as upper limits on dark photon kinetic mixing and axionlike particle axioelectric coupling for masses between 1.2 and <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline"><f:mn>23.3</f:mn><f:mtext> </f:mtext><f:mtext> </f:mtext><f:mi>eV</f:mi><f:mo>/</f:mo><f:msup><f:mi>c</f:mi><f:mn>2</f:mn></f:msup></f:math>. Compared to an earlier HVeV search, sensitivity was improved as a result of an increased overburden of 225 meters of water equivalent, an anticoincidence event selection, and better pile-up rejection. In the case of dark-matter-electron scattering via a heavy mediator, an improvement by up to a factor of 25 in cross section sensitivity was achieved.