A scalar-extended U(1)Lμ−Lτ explanation of the LUX-ZEPLIN 248 keV excess
Abstract
The recently observed dark matter (DM) nuclear recoil event at an energy of 248 ± 23 (stat.) ± 23 (syst.) keV at the LUX-ZEPLIN (LZ) experiment, favoring an inelastic scattering interpretation, has motivated various beyond the Standard Model (BSM) scenarios aimed at explaining the observed excess. In particular, this provides an opportunity to probe models that naturally accommodate inelastic DM scattering. In this work, we explore one such possibility by extending the U(1)Lμ−Lτ model with two complex scalar fields, Φ and S, carrying charges −1 and +2, respectively, under the U(1)Lμ−Lτ gauge symmetry. These charge assignments allow a trilinear interaction between the two scalar fields, which is crucial for generating the DM mass splitting. Following the spontaneous breaking of the U(1)Lμ−Lτ symmetry, with S acquiring a vacuum expectation value and generating a mass for the BSM gauge boson Zμτ, the real and imaginary components of Φ acquire a mass splitting. This naturally gives rise to an inelastic DM scattering scenario that can accommodate the LZ excess. We perform a likelihood-based assessment of the sensitivity of the model parameters to the observed event while consistently accounting for other relevant phenomenological constraints. Finally, we discuss the prospects for probing the viable parameter space at future experiments.
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BibTeX
@misc{pradhan2026scalarextended,
title = {{A scalar-extended $\rm U(1)_L_μ-L_τ$ explanation of the LUX-ZEPLIN 248 keV excess}},
author = {Dipankar Pradhan and Abhik Sarkar},
howpublished = {HAL},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.12443},
eprint = {2610.12443},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05829958v1},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A scalar-extended U(1)_L_μ−L_τ explanation of the LUX-ZEPLIN 248 keV excess
AU - Dipankar Pradhan
AU - Abhik Sarkar
PY - 2026
DA - 2026/10/21
PB - HAL
DO - 10.48550/arxiv.2610.12443
UR - https://hal.science/hal-05829958v1
AB - The recently observed dark matter (DM) nuclear recoil event at an energy of 248 ± 23 (stat.) ± 23 (syst.) keV at the LUX-ZEPLIN (LZ) experiment, favoring an inelastic scattering interpretation, has motivated various beyond the Standard Model (BSM) scenarios aimed at explaining the observed excess. In particular, this provides an opportunity to probe models that naturally accommodate inelastic DM scattering. In this work, we explore one such possibility by extending the U(1)_L_μ−L_τ model with two complex scalar fields, Φ and S, carrying charges −1 and +2, respectively, under the U(1)_L_μ−L_τ gauge symmetry. These charge assignments allow a trilinear interaction between the two scalar fields, which is crucial for generating the DM mass splitting. Following the spontaneous breaking of the U(1)_L_μ−L_τ symmetry, with S acquiring a vacuum expectation value and generating a mass for the BSM gauge boson Z_μτ, the real and imaginary components of Φ acquire a mass splitting. This naturally gives rise to an inelastic DM scattering scenario that can accommodate the LZ excess. We perform a likelihood-based assessment of the sensitivity of the model parameters to the observed event while consistently accounting for other relevant phenomenological constraints. Finally, we discuss the prospects for probing the viable parameter space at future experiments.
ER -