Probing Leptophilic Scalar Dark Matter with SMEFT and Direct Detection
Abstract
Heavy dark sectors may evade direct production at current colliders while leaving measurable imprints in precision observables and dark matter searches. We study leptophilic scalar dark matter within the Standard Model Effective Field Theory (SMEFT), considering both real and complex scalar dark matter coupled to vector-like leptonic mediators. We perform the complete one-loop matching of the model onto the dimension-six Warsaw basis and combine the resulting precision constraints with predictions for direct and indirect detection. We compute the relic abundance including coannihilations with the mediator, Sommerfeld enhancement, bound-state formation, and one-loop corrections to scalar dark matter annihilation. We also derive the effective dark matter-photon interactions relevant for nuclear recoils, retaining the full dependence on the dark matter and mediator masses and extending previous results beyond the heavy-mediator limit. We find that global SMEFT fits provide competitive constraints for dark matter masses up to approximately $850$ GeV, while direct detection becomes particularly powerful for compressed spectra. The complex scalar scenario is strongly constrained by the charge-radius interaction, whereas real scalar dark matter remains viable across a substantial region of parameter space. Finally, we show that a modified cosmological expansion history can significantly shift the relic-density-compatible parameter space, thereby changing the complementarity among the different probes.
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BibTeX
@misc{biondini2026probing,
title = {{Probing Leptophilic Scalar Dark Matter with SMEFT and Direct Detection}},
author = {Simone Biondini and Chiara Megan Bolloni and Orlando Panella and Lorenzo Tiberi},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.26512},
eprint = {2610.26512},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.26512},
}
RIS
TY - UNPB
TI - Probing Leptophilic Scalar Dark Matter with SMEFT and Direct Detection
AU - Simone Biondini
AU - Chiara Megan Bolloni
AU - Orlando Panella
AU - Lorenzo Tiberi
PY - 2026
DA - 2026/10/19
PB - arXiv
DO - 10.48550/arxiv.2610.26512
UR - https://arxiv.org/abs/2610.26512
AB - Heavy dark sectors may evade direct production at current colliders while leaving measurable imprints in precision observables and dark matter searches. We study leptophilic scalar dark matter within the Standard Model Effective Field Theory (SMEFT), considering both real and complex scalar dark matter coupled to vector-like leptonic mediators. We perform the complete one-loop matching of the model onto the dimension-six Warsaw basis and combine the resulting precision constraints with predictions for direct and indirect detection. We compute the relic abundance including coannihilations with the mediator, Sommerfeld enhancement, bound-state formation, and one-loop corrections to scalar dark matter annihilation. We also derive the effective dark matter-photon interactions relevant for nuclear recoils, retaining the full dependence on the dark matter and mediator masses and extending previous results beyond the heavy-mediator limit. We find that global SMEFT fits provide competitive constraints for dark matter masses up to approximately $850$ GeV, while direct detection becomes particularly powerful for compressed spectra. The complex scalar scenario is strongly constrained by the charge-radius interaction, whereas real scalar dark matter remains viable across a substantial region of parameter space. Finally, we show that a modified cosmological expansion history can significantly shift the relic-density-compatible parameter space, thereby changing the complementarity among the different probes.
ER -