Improving sensitivity to low-mass dark matter in LUX using a novel electrode background mitigation technique

Akerib, DS, Alsum, S, Araujo, HM, Bai, X, Balajthy, J, Bang, J, Baxter, A, Bernard, EP, Bernstein, A, Biesiadzinski, TP
et al (show 87 more authors) (2021) Improving sensitivity to low-mass dark matter in LUX using a novel electrode background mitigation technique. PHYSICAL REVIEW D, 104 (1). 012011-.

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This paper presents a novel technique for mitigating electrode backgrounds that limit the sensitivity of searches for low-mass dark matter (DM) using xenon time projection chambers. In the Large Underground Xenon (LUX) detector, signatures of low-mass DM interactions would be very low-energy () scatters in the active target that ionize only a few xenon atoms and seldom produce detectable scintillation signals. In this regime, extra precaution is required to reject a complex set of low-energy electron backgrounds that have long been observed in this class of detector. Noticing backgrounds from the wire grid electrodes near the top and bottom of the active target are particularly pernicious, we develop a machine learning technique based on ionization pulse shape to identify and reject these events. We demonstrate the technique can improve Poisson limits on low-mass DM interactions by a factor of 1.7-3 with improvement depending heavily on the size of ionization signals. We use the technique on events in an effective 5 tonne·day exposure from LUX’s 2013 science operation to place strong limits on low-mass DM particles with masses in the range . This machine learning technique is expected to be useful for near-future experiments, such as LUX-ZEPLIN and XENONnT, which hope to perform low-mass DM searches with the stringent background control necessary to make a discovery.

Item Type: Article
Uncontrolled Keywords: 5106 Nuclear and Plasma Physics, 5107 Particle and High Energy Physics, 51 Physical Sciences
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 15 Dec 2021 16:18
Last Modified: 20 Jun 2024 22:05
DOI: 10.1103/PhysRevD.104.012011
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