Inferring dark matter masses and interactions from high recoil energy events in LUX-ZEPLIN
Abstract
LUX-ZEPLIN has recently revealed a single nuclear recoil event compatible with a recoil energy of ER≃248 keV, in a region with a small expected background. Interpreting this as a signature of dark matter, we compute the posterior probability distribution of the parameters of the dark matter scattering off xenon nuclei. We retain the exact two-body kinematics for an arbitrary mass splitting between the incoming and outgoing dark-sector states, thus encompassing both elastic and inelastic scatterings. The data select non-trivial, disconnected regions of this distribution, which correspond to physically distinct endothermic and exothermic regimes, in which the observed recoil is generated either close to a kinematic threshold or through the release of dark-sector mass energy. We determine the recoil spectra preferred by the observed data and show how the absence of accompanying events at lower recoil energies sharply constrains the viable parameter space. We find a kinematically tuned region of endothermic WIMP-like models at high mass for generic couplings, as well as exothermic models ranging from sub-GeV to heavy dark matter with sizable mass splittings. Elastic dark matter scatterings require instead momentum-suppressed and/or nuclear-spin-dependent non-relativistic interactions.
Related
- Search for dark matter particle interactions in an extended nuclear recoil energy window with the LUX-ZEPLIN (LZ) experiment
- Inelastic Dark Matter and High-Energy Recoil Signatures in LZ
- Explaining the LZ High-Energy Recoil Event with Inelastic Sneutrino Dark Matter in Supersymmetry
- Inelastic Dark Matter and High-Energy Recoil Signatures in LZ
- Inelastic Dark Matter Signature at High Recoil Energy in LUX-ZEPLIN and CRESST
BibTeX
@misc{palmisano2026inferring,
title = {{Inferring dark matter masses and interactions from high recoil energy events in LUX-ZEPLIN}},
author = {Stefano Palmisano and Michele Tammaro and Andrea Tesi},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.15985},
eprint = {2609.15985},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.15985},
}
RIS
TY - UNPB
TI - Inferring dark matter masses and interactions from high recoil energy events in LUX-ZEPLIN
AU - Stefano Palmisano
AU - Michele Tammaro
AU - Andrea Tesi
PY - 2026
DA - 2026/09/18
PB - arXiv
DO - 10.48550/arxiv.2609.15985
UR - https://arxiv.org/abs/2609.15985
AB - LUX-ZEPLIN has recently revealed a single nuclear recoil event compatible with a recoil energy of E_R≃248 keV, in a region with a small expected background. Interpreting this as a signature of dark matter, we compute the posterior probability distribution of the parameters of the dark matter scattering off xenon nuclei. We retain the exact two-body kinematics for an arbitrary mass splitting between the incoming and outgoing dark-sector states, thus encompassing both elastic and inelastic scatterings. The data select non-trivial, disconnected regions of this distribution, which correspond to physically distinct endothermic and exothermic regimes, in which the observed recoil is generated either close to a kinematic threshold or through the release of dark-sector mass energy. We determine the recoil spectra preferred by the observed data and show how the absence of accompanying events at lower recoil energies sharply constrains the viable parameter space. We find a kinematically tuned region of endothermic WIMP-like models at high mass for generic couplings, as well as exothermic models ranging from sub-GeV to heavy dark matter with sizable mass splittings. Elastic dark matter scatterings require instead momentum-suppressed and/or nuclear-spin-dependent non-relativistic interactions.
ER -