Pushing the Limits of Pulse Shape Discrimination in a Large Liquid Xenon Detector
Abstract
The LUX-ZEPLIN (LZ) experiment is a direct-detection dark matter experiment, optimized to search for weakly interacting massive particles (WIMPs) through WIMP-nucleon interactions. The main challenge in dark matter detection is differentiating between WIMP signals and background events. In LZ, the ratio of ionization to scintillation signals (charge-to-light) is the primary method for rejecting electronic recoil (ER) background. Pulse shape discrimination (PSD) offers a method for additional ER backgrounds rejection in liquid xenon detectors. In this paper, the discrimination power of PSD with the LZ experiment is discussed. To precisely characterize the scintillation pulse shape, an analysis framework is developed to reconstruct the detection time of individual photons. Using LZ calibration data, the photon-timing prompt fraction discriminator is optimized and achieves ER leakage as low as . For specific background processes such as Xe double electron capture, the leakage is reduced further to about . PSD is combined with charge-to-light to form two-factor discrimination (TFD). The optimized TFD performance is compared with the performance of the charge-to-light method, with the corresponding false positive rate reduced by up to a factor of two for large scintillation pulses. Finally, PSD and TFD are applied to data from LZ's WS2024 run and their performance is summarized.
Keywords
Cite
@article{arxiv.2603.26877,
title = {Pushing the Limits of Pulse Shape Discrimination in a Large Liquid Xenon Detector},
author = {D. S. Akerib and A. K. Al Musalhi and F. Alder and B. J. Almquist and C. S. Amarasinghe and A. Ames and T. J. Anderson and N. Angelides and H. M. Araújo and J. E. Armstrong and M. Arthurs and A. Baker and S. Balashov and J. Bang and J. W. Bargemann and E. E. Barillier and K. Beattie and A. Bhatti and T. P. Biesiadzinski and H. J. Birch and E. Bishop and G. M. Blockinger and C. A. J. Brew and P. Brás and S. Burdin and M. C. Carmona-Benitez and M. Carter and A. Chawla and H. Chen and Y. T. Chin and N. I. Chott and S. Contreras and M. V. Converse and R. Coronel and A. Cottle and G. Cox and D. Curran and C. E. Dahl and I. Darlington and S. Dave and A. David and J. Delgaudio and S. Dey and L. de Viveiros and L. Di Felice and C. Ding and J. E. Y. Dobson and E. Druszkiewicz and S. Dubey and C. L. Dunbar and S. R. Eriksen and N. M. Fearon and N. Fieldhouse and S. Fiorucci and H. Flaecher and E. D. Fraser and T. M. A. Fruth and P. W. Gaemers and R. J. Gaitskell and A. Geffre and J. Genovesi and C. Ghag and J. Ghamsari and A. Ghosh and S. Ghosh and R. Gibbons and S. Gokhale and J. Green and M. G. D. van der Grinten and J. J. Haiston and C. R. Hall and T. Hall and R. H. Hampp and S. J. Haselschwardt and M. A. Hernandez and S. A. Hertel and G. J. Homenides and M. Horn and D. Q. Huang and D. Hunt and E. Jacquet and R. S. James and K. Jenkins and A. C. Kaboth and A. C. Kamaha and M. K. Kannichankandy and D. Khaitan and A. Khazov and J. Kim and Y. D. Kim and D. Kodroff and E. V. Korolkova and H. Kraus and S. Kravitz and L. Kreczko and V. A. Kudryavtsev and C. Lawes and E. B. Leon and D. S. Leonard and K. T. Lesko and C. Levy and J. Lin and A. Lindote and W. H. Lippincott and J. Long and M. I. Lopes and W. Lorenzon and C. Lu and S. Luitz and W. Ma and V. Mahajan and P. A. Majewski and A. Manalaysay and R. L. Mannino and R. J. Matheson and C. Maupin and M. E. McCarthy and D. N. McKinsey and J. McLaughlin and J. B. McLaughlin and R. McMonigle and B. Mitra and E. Mizrachi and M. E. Monzani and K. Morå and E. Morrison and B. J. Mount and M. Murdy and A. St. J. Murphy and H. N. Nelson and F. Neves and A. Nguyen and C. L. O'Brien and F. H. O'Shea and I. Olcina and K. C. Oliver-Mallory and J. Orpwood and K. Y. Oyulmaz and K. J. Palladino and N. J. Pannifer and S. J. Patton and B. Penning and G. Pereira and E. Perry and T. Pershing and A. Piepke and S. S. Poudel and Y. Qie and J. Reichenbacher and C. A. Rhyne and G. R. C. Rischbieter and E. Ritchey and H. S. Riyat and R. Rosero and N. J. Rowe and T. Rushton and D. Rynders and S. Saltão and D. Santone and A. B. M. R. Sazzad and R. W. Schnee and G. Sehr and B. Shafer and S. Shaw and W. Sherman and K. Shi and T. Shutt and C. Silva and G. Sinev and J. Siniscalco and A. M. Slivar and A. M. Softley-Brown and V. N. Solovov and P. Sorensen and J. Soria and T. J. Sumner and A. Swain and M. Szydagis and D. R. Tiedt and D. R. Tovey and J. Tranter and M. Trask and K. Trengove and M. Tripathi and A. Usón and A. C. Vaitkus and O. Valentino and V. Velan and A. Wang and J. J. Wang and Y. Wang and L. Weeldreyer and T. J. Whitis and K. Wild and M. Williams and J. Winnicki and L. Wolf and F. L. H. Wolfs and S. Woodford and D. Woodward and C. J. Wright and Q. Xia and J. Xu and Y. Xu and M. Yeh and D. Yeum and J. Young and W. Zha and H. Zhang and T. Zhang and Y. Zhou},
journal= {arXiv preprint arXiv:2603.26877},
year = {2026}
}
Comments
16 pages, 14 figures