Dark Matter “Collider” from Inelastic Boosted Dark Matter

We propose a novel dark matter (DM) detection strategy for models with a nonminimal dark sector. The main ingredients in the underlying DM scenario are a boosted DM particle and a heavier dark sector state. The relativistic DM impinged on target material scatters off inelastically to the heavier state, which subsequently decays into DM along with lighter states including visible (standard model) particles. The expected signal event, therefore, accompanies a visible signature by the secondary cascade process associated with a recoiling of the target particle, differing from the typical neutrino signal not involving the secondary signature. We then discuss various kinematic features followed by DM detection prospects at large-volume neutrino detectors with a model framework where a dark gauge boson is the mediator between the standard model particles and DM.

Figure 1

Inelastic boosted DM direct-detection scenarios under consideration.

Figure 2

Expected unit-normalized energy spectra of the recoiling target particles from the primary vertex (left panels) and outgoing mediators from the secondary vertex (right panels) for $e$ scattering (top panels) and $p$ scattering (bottom panels). The reference masses are in unit of GeV.

Figure 3

Left: Angular separation between the recoiling target and ${\chi }_2$ (red solid and blue dashed lines) or the mediator $\varphi$ (temperature-scaled regions). Right: Angular separation between the $e^{+}{e}^{-}$ pair from the $\varphi$ decay.

Figure 4

$e$ scattering (upper panels) and $p$ scattering (lower panels) parameters in SK and HK (left panels) and DUNE (right panels). For $e$ scattering we scan for $\delta m_{\chi }=0.1$, 0.2 GeV while for $p$ scattering we scan for $\delta m_{\chi }=0.5$, 1, 1.5, 2 GeV. Black contours show maximally allowed $m_{{\chi }_2}$ values in GeV and the red crosses show our reference parameters.