Searching for Afterglow: Light Dark Matter Boosted by Supernova Neutrinos
Yen-Hsun Lin, Wen-Hua Wu, Meng-Ru Wu, H. T. Wong
Abstract
A novel analysis is performed, incorporating time-of-flight (TOF) information to study the interactions of dark matter (DM) with standard model particles. After supernova (SN) explosions, DM with mass ${m}_{\ensuremath{\chi}}\ensuremath{\lesssim}\mathcal{O}(\mathrm{MeV})$ in the halo can be boosted by SN neutrinos ($\mathrm{SN}\ensuremath{\nu}$) to relativistic speed. The $\mathrm{SN}\ensuremath{\nu}$ boosted DM (BDM) arrives on Earth with TOF which depends only on ${m}_{\ensuremath{\chi}}$ and is independent of the cross section. These BDMs can interact with detector targets in low-background experiments and manifest as afterglow events after the arrival of $\mathrm{SN}\ensuremath{\nu}$. The characteristic TOF spectra of the BDM events can lead to large background suppression and unique determination of ${m}_{\ensuremath{\chi}}$. New cross section constraints on $\sqrt{{\ensuremath{\sigma}}_{\ensuremath{\chi}e}{\ensuremath{\sigma}}_{\ensuremath{\chi}\ensuremath{\nu}}}$ are derived from SN1987a in the Large Magellanic Cloud with data from the Kamiokande and Super-Kamiokande experiments. Potential sensitivities for the next galactic SN with Hyper-Kamiokande are projected. This analysis extends the existing bounds on $\sqrt{{\ensuremath{\sigma}}_{\ensuremath{\chi}e}{\ensuremath{\sigma}}_{\ensuremath{\chi}\ensuremath{\nu}}}$ over a broad range of ${r}_{\ensuremath{\chi}}={\ensuremath{\sigma}}_{\ensuremath{\chi}\ensuremath{\nu}}/{\ensuremath{\sigma}}_{\ensuremath{\chi}e}$. In particular, the improvement is by 1--3 orders of magnitude for ${m}_{\ensuremath{\chi}}<\mathcal{O}(100\text{ }\text{ }\mathrm{keV})$ for ${\ensuremath{\sigma}}_{\ensuremath{\chi}e}\ensuremath{\sim}{\ensuremath{\sigma}}_{\ensuremath{\chi}\ensuremath{\nu}}$. Prospects of exploiting TOF information in other astrophysical systems to probe exotic physics with other DM candidates are discussed.