Background determination for the LUX-ZEPLIN dark matter experiment

• Published in: Physical review. D 2023-07, Vol.108 (1), Article 012010
• Main Authors: Aalbers, J., Akerib, D. S., Musalhi, A. K. Al, Alder, F., Alsum, S. K., Amarasinghe, C. S., Ames, A., Anderson, T. J., Angelides, N., Araújo, H. M., Armstrong, J. E., Arthurs, M., Baker, A., Bang, J., Bargemann, J. W., Baxter, A., Beattie, K., Beltrame, P., Bernard, E. P., Bhatti, A., Biekert, A., Biesiadzinski, T. P., Birch, H. J., Blockinger, G. M., Boxer, B., Brew, C. A. J., Brás, P., Burdin, S., Buuck, M., Cabrita, R., Carmona-Benitez, M. C., Chan, C., Chawla, A., Chen, H., Chiang, A. P. S., Chott, N. I., Converse, M. V., Cottle, A., Cox, G., Creaner, O., Dahl, C. E., David, A., Dey, S., de Viveiros, L., Ding, C., Dobson, J. E. Y., Druszkiewicz, E., Eriksen, S. R., Fan, A., Fearon, N. M., Fiorucci, S., Flaecher, H., Fraser, E. D., Fruth, T., Gaitskell, R. J., Genovesi, J., Ghag, C., Gibbons, R., Gilchriese, M. G. D., Gokhale, S., Green, J., van der Grinten, M. G. D., Gwilliam, C. B., Hall, C. R., Han, S., Hartigan-O’Connor, E., Haselschwardt, S. J., Hertel, S. A., Heuermann, G., Horn, M., Huang, D. Q., Hunt, D., Ignarra, C. M., Jacobsen, R. G., Jahangir, O., James, R. S., Johnson, J., Kaboth, A. C., Kamaha, A. C., Khaitan, D., Khurana, I., Kirk, R., Kodroff, D., Korley, L., Korolkova, E. V., Kraus, H., Kravitz, S., Kreczko, L., Krikler, B., Kudryavtsev, V. A., Leason, E. A., Lee, J., Leonard, D. S., Lesko, K. T., Levy, C., Lin, J., Lindote, A., Linehan, R., Lippincott, W. H., Liu, X.
• Format: Article
• Language: English
• Subjects: dark matter detectors; INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; particle dark matter; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; weakly interacting massive particles
• ISSN: 2470-0010; 2470-0029
• DOI: 10.1103/PhysRevD.108.012010

The LUX-ZEPLIN experiment recently reported limits on WIMP-nucleus interactions from its initial science run, down to 9.2 x 10–48 cm2 for the spin-independent interaction of a 36 GeV/c2 WIMP at 90% confidence level. In this paper, we present a comprehensive analysis of the backgrounds important for this result and for other upcoming physics analyses, including neutrinoless double-beta decay searches and effective field theory interpretations of LUX-ZEPLIN data. We confirm that the in-situ determinations of bulk and fixed radioactive backgrounds are consistent with expectations from the ex-situ assays. The observed background rate after WIMP search criteria were applied was (6.3 ± 0.5) x 10–5 events /keVee/kg/day in the low-energy region, approximately 60 times lower than the equivalent rate reported by the LUX experiment.