Dark matter annual modulation analysis with combined nuclear and electron recoil channels

Abstract

After decades of experimental efforts, the DAMA/LIBRA(DL) annual modulation (AM) analysis on the χN (WIMP dark matter interactions on nucleus) channel remains the only one which can be interpreted as positive signatures. This has been refuted by numerous time-integrated (TI) and AM analysis. It has been shown that χe (WIMP interactions with electrons) alone is not compatible with the DL AM data. We expand the investigations by performing an AM analysis with the addition of χe long-range and short-range interactions to χN, derived using the frozen core approximation method. Two scenarios are considered, where the χN and χe processes are due to a single χ (Γtot1χ) or two different χ's (Γtot2χ). The combined fits with χN and χe provide stronger significance to the DL AM data which are compatible with the presence of additional physical effects beyond χN alone. This is the first analysis which explores how χe AM can play a role in DL AM. The revised allowed regions as well as the exclusion contours from the other null AM experiments are presented. All DL AM allowed parameter spaces in χN and χe channels under both Γtot1χ and Γtot2χ are excluded at the 90% confidence level by the combined null AM results. It can be projected that DL-allowed parameter spaces from generic models with interactions induced by two-WIMPs are ruled out. © 2025 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.