Year: 2026
Type: preprint
Abstract: The Sun acts as a natural dark matter accelerator. Galactic halo particles scattering in the solar plasma emerge with velocities well beyond the Galactic escape speed, providing a boosted flux that extends the kinematic reach of direct detection experiments into the sub-MeV mass regime. We present constraints on solar-reflected dark matter (SRDM) from the DAMIC-M prototype detector using $\sim$1.3~kg-day of data acquired with silicon skipper charge coupled devices (CCDs) at the Modane Underground Laboratory. Exploiting the spatial diffusion signature of low-energy electron recoils, we derive 90% C.L. upper limits on the DM-electron scattering cross section for both heavy- and ultralight-mediator benchmarks, reaching $\barσ_e\sim 3.16 \cdot 10^{-37} \rm{cm^2}$ at $0.1$ MeV. For the ultralight mediator, our limits are competitive with the world-leading constraints, achieved with an integrated exposure of $\sim1.3$~kg-day. These results probe the parameter space between stellar-cooling bounds and terrestrial limits from standard halo searches, a region inaccessible to direct detection experiments relying solely on the standard halo flux.
Source: arXiv (Cornell University)
Authors: Aggarwal, K., Arnquist, I., Avalos, N., Bertou, X., Castello-Mor, N., Centeno-Lorca, C., Chavarria, A. E., Chriss, A. R., Cuevas-Zepeda, J., Dastgheibi-Fard, A., De Dominicis, C., Deligny, O., Duarte-Campderros, J., Estrada, E., Gaıor, R., Gkougkousis, E. -L., Hossbach, T., Iddir, L., Kavanagh, B. J., Kilminster, B., Lawson, I., Letessier-Selvon, A., Lin, H., Loaiza, P., Lopez-Virto, A., Lou, R., Lumengo-Kidimbu, H., Munagavalasa, S., Noonan, J., Norcini, D., Paul, S., Perez-Cobo, P., Privitera, P., Robmann, P., Roach, B., Rosenmerkel, D., Settimo, M., Smida, R., Traina, M., Vilar, R., Yajur, R., Venegas-Vargas, D., Zhu, C., Zhu, Y.
Institutions: University of Washington, Pacific Northwest National Laboratory, Centre National de la Recherche Scientifique, Université Paris Cité, Sorbonne Université, Laboratoire de Physique Nucléaire et de Hautes Énergies, Institut National de Physique Nucléaire et de Physique des Particules, Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie, Instituto de Física de Cantabria, Université Grenoble Alpes, Bariloche Atomic Centre, University of Zurich, Snolab, Johns Hopkins University, Johns Hopkins Medicine, University of Baltimore, Laboratoire de Physique Subatomique et des Technologies Associées, IMT Atlantique, Nantes Université, Balseiro Institute
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7168126377
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