Fermionic sub-GeV Dark Matter from evaporating Primordial Black Holes at DarkSide-50

Abstract

We present a search for boosted dark matter from Primordial Black Holes (PBH) evaporation using the DarkSide-50 ionization-signal-only dataset corresponding to the experiment's ($12202\pm180$) ${\rm kg\: d}$ exposure. We focus on evaporation of PBHs with masses in the range [$10^{14},\,10^{16}$] g producing Dirac fermionic dark matter particles with sub-GeV kinetic energy. These relativistic particles, with energies up to hundreds of MeV, can generate detectable signals for masses below $\mathcal{O}(100)$ MeV. The absence of a signal enables setting complementary limits to those derived from cosmological observations and direct detection searches for cosmic ray-boosted dark matter.

Figures (4)

• Figure 1: Diffuse DM differential flux from evaporating PBHs as a function of its kinetic energy. The solid lines show the galactic components, while the dashed lines the extragalactic ones. With different colors, we identify different PBH masses and abundances.
• Figure 2: Expected rate assuming M$_{\rm PBH} = 1.0\times10^{15}\,$g and $f_{\rm PBH} = 4.1\times10^{-7}$ for different spin-independent cross-sections.
• Figure 3: The data spectrum (black points) and the best background-only fit result (gray line). As an example, signal spectra for three different values of $\sigma^{\rm SI}_{\chi}$ and M$_{\rm PBH}$ at $m_{\chi} = 1\:{\rm MeV}$ are shown by the yellow, purple, and blue lines. As shown in Fig. \ref{['fig:fluxes']}, lighter PBHs result in harder DM spectra.
• Figure 4: The 90% C.I. observed (solid lines) and expected (dashed lines) limit on the DM cross-section $\sigma^{\rm SI}{\chi}$ as a function of the DM mass, assuming a Dirac fermion DM candidate, and for three different values of the PBH mass for the final DS-50 exposure of 12202 $\pm$ 180 kg d. The parameter $f_\mathrm{PBH}$ is fixed by the constraints of Refs. Carr:2020goxIguaz:2021irx (see the text for further details). For comparison, we report DM constraints from (1) cosmic-ray boosted DM particles Bringmann:2018cvkCappiello:2019qswPandaX-II:2021kai, (2) from the CRESST experiment (in the standard halo model scenario) CRESST:2017uesCRESST:2019jnq, (3) from cosmology Gluscevic:2017ywpXu:2018efhSlatyer:2018aqgNadler:2019zrb, and (4) from CDEX-10 CDEX:2022dda, whose results were obtained in a similar scenario.