Improved calculations of beta decay backgrounds to new physics in liquid xenon detectors

Abstract

We present high-precision theoretical predictions for the electron energy spectra for the ground-state to ground-state $\beta$ decays of ${}^{214}$Pb, ${}^{212}$Pb, and ${}^{85}$Kr most relevant to the background of liquid xenon dark matter detectors. The effects of nuclear structure on the spectral shapes are taken into account using large-scale shell model calculations. Final spectra also include atomic screening and exchange effects. The impact of nuclear structure effects on the ${}^{214}$Pb and ${}^{212}$Pb spectra below $\approx 100$ keV, pertinent for several searches for new physics, are found to be comparatively larger than those from the atomic effects alone. We find that the full calculation for ${}^{214}$Pb (${}^{212}$Pb) predicts 15.0-23.2% (12.1-19.0%) less event rate in a 1-15 keV energy region of interest compared to the spectrum calculated as an allowed transition when using values of the weak axial vector coupling in the range $g_{\mathrm{A}}=0.7-1.0$. The discrepancy highlights the importance of both a proper theoretical treatment and the need for direct measurements of these spectra for a thorough understanding of $\beta$ decay backgrounds in future experiments.

arXiv comment7 pages, 3 figures; v3 matches version in Phys. Rev. C; v2&v3 include updated Q-values, results unchanged

References in corpus (10)

• Excess Electronic Recoil Events in XENON1T
• Projected WIMP sensitivity of the LUX-ZEPLIN (LZ) dark matter experiment
• Projected WIMP Sensitivity of the XENONnT Dark Matter Experiment
• An improved calculation of the isospin-symmetry-breaking corrections to superallowed Fermi beta decay
• Value of the axial-vector coupling strength in $\beta$ and $\beta \beta$ decays: A review
• High precision analytical description of the allowed $\beta$ spectrum shape
• Removing krypton from xenon by cryogenic distillation to the ppq level
• Chromatographic separation of radioactive noble gases from xenon
• Second-forbidden nonunique ${\beta }^{-}$ decays of ${}^{24}$Na and ${}^{36}$Cl assessed by the nuclear shell model
• Measurement of the Spectral Shape of the beta-decay of 137Xe to the Ground State of 137Cs in EXO-200 and Comparison with Theory

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• Measurement of Double Beta Decay Half-life of ${}^{136}$Xe with the PandaX-4T Detector
• DarkSide-20k sensitivity to light dark matter particles
• Updated evaluation of potential ultra-low Q value $\beta$-decay candidates
• Exchange correction for allowed $\beta$-decay
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• Dark Fluxes from Accreting Black Holes and Direct Detections
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• Atomic corrections for the unique first forbidden $\beta$ transition of ${}^{187}$Re
• Double-beta decay of ${}^{150}$Nd to excited levels of ${}^{150}$Sm
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