The search for light dark matter

by Prof. Kathryn Zurek (Caltech)

Friday 12 Dec 2025, 14:30 → 16:30 Europe/Rome

1/1-3 - Aula B (Dipartimento di Fisica e Astronomia - Edificio Marzolo)

 We review dark matter (DM) candidates of a very low mass, appearing in
the window below the traditional weakly-interacting massive particle mχ
≲ 10 GeV and extending down to mχ ≳ meV, somewhat below the mass limit
where DM becomes wavelike. Such candidates are motivated by hidden
sectors such as Hidden Valleys, which feature hidden forces and rich
dynamics, but have evaded traditional collider searches looking for New
Physics because of their relatively weak coupling to the Standard Model.
Such sectors can still be detected through dedicated low-energy
colliders which, through their intense beams, can have sensitivity to
smaller couplings, or through astrophysical observations of the
evolution of DM halos and stellar structures which, through the
Universe's epochs, can be sensitive to small DM interactions. We also
consider mechanisms where the DM abundance is fixed through the
interaction with the SM, which directly motivates the search for light
DM in terrestrial experiments. The bulk of the talk will be dedicated to
the new ideas that have been proposed for directly detecting such DM
candidates of a low mass, through nuclear recoils, electronic
excitations, or collective modes such as phonons and magnons. The rich
tapestry of materials and modes in the Condensed Matter landscape is
reviewed, along with specific prospects for detection.