Speaker
Description
The LUX-ZEPLIN (LZ) experiment recently reported a nuclear recoil candidate at $E_R \simeq 248 $ keV. Inelastic dark matter (DM) is among the best-motivated explanations of this signal, since it suppresses the low-energy recoils that elastic scattering would predict. However, in thermal freeze-out the relic density fixes the DM–nucleon cross section for a given mass. In this talk, based on arXiv:2609.13130, we will consider a pseudo-Dirac fermion with a heavy $Z^\prime$ mediator, produced via freeze-in with a reheating temperature $T_R$ below the DM mass. We will show that $T_R$ breaks the one-to-one relation between mass and cross section. As a result, the LZ candidate is reproduced over a continuous region of parameter space, including splittings below the thermal benchmark, with $m_\chi ≃ 0.5–1$ TeV as the most favourable range.
| Which topic best fits your talk? | High Energy Physics and Particles |
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| Affiliations | University of Aveiro |