Dortmund 2021 – scientific programme
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T: Fachverband Teilchenphysik
T 95: Searches for Dark Matter III
T 95.1: Talk
Thursday, March 18, 2021, 16:00–16:15, Tt
New measurement of the photoelectric absorption cross section near the silicon band gap for dark matter searches — •Matthew Wilson1,2 and Belina von Krosigk1 — 1Universität Hamburg, Hamburg, Deutschland — 2University of Toronto, Toronto, Canada
Cryogenic silicon as a detection medium is used for various direct dark matter search experiments. Many of these experiments are sensitive to low-mass dark matter candidates that rely directly or indirectly on the temperature-dependent photoelectric absorption cross section of silicon near the band gap. While this cross section data from the literature is lacking, previous dark matter search experiments have attempted to estimate this parameter by extrapolating it from higher temperature measurements. However, discrepancies in the underlying literature data have resulted in dominating systematic uncertainties on dark matter limits. This presentation shows the results of using a novel technique to make a direct, low-temperature measurement of the photoelectric absorption cross section of silicon at energies near the band gap, and discusses the effect this new measurement has on the exclusion limits from various dark matter candidates.