Effect on dark matter exclusion limits from new silicon photoelectric absorption measurements

• Published in: Physical review. D 2021-09, Vol.104 (6), p.1, Article 063002
• Main Authors: von Krosigk, B., Wilson, M. J., Stanford, C., Cabrera, B., Calkins, R., Jardin, D., Kurinsky, N. A., Ponce, F., Wu, C.-P.
• Format: Article
• Language: English
• Subjects: Absorption cross sections; Cryogenic temperature; Dark matter; Holes (electron deficiencies); Particle interactions; Photoelectricity; Searching; Sensitivity; Silicon; Single electrons
• ISSN: 2470-0010; 2470-0029
• DOI: 10.1103/PhysRevD.104.063002

Recent breakthroughs in cryogenic silicon detector technology allow for the observation of single electron-hole pairs released via particle interactions within the target material. This implies sensitivity to energy depositions as low as the smallest band gap, which is ∼ 1.2     eV for silicon, and therefore sensitivity to eV / c2-scale bosonic dark matter and to thermal dark matter at masses below 100     MeV / c2. Various interaction channels that can probe the lowest currently accessible masses in direct searches are related to standard photoelectric absorption. In any of these respective dark matter signal models any uncertainty on the photoelectric absorption cross section is propagated into the resulting exclusion limit or into the significance of a potential observation. Using first-time precision measurements of the photoelectric absorption cross section in silicon recently performed at Stanford University, this article examines the importance having accurate knowledge of this parameter at low energies and cryogenic temperatures for these dark matter searches.