Directional Neutrino Searches for Galactic Center Dark Matter at Large Underground LArTPCs

TL;DR

This paper explores how large underground LArTPC neutrino detectors can improve dark matter detection from the Galactic Center by utilizing directional information of neutrino events, potentially surpassing current limits.

Contribution

It demonstrates the potential of directional neutrino detection in large LArTPCs to enhance sensitivity to dark matter annihilation signals, especially with improved electron directionality algorithms.

Findings

LArTPC detectors can set competitive limits on dark matter annihilation for masses above 30 MeV.

Directional information can significantly improve sensitivity below 15 MeV where backgrounds are high.

Current angular resolution is insufficient, but future improvements could enhance detection capabilities.

Abstract

We investigate the sensitivity of a large, underground LArTPC-based neutrino detector to dark matter in the Galactic Center annihilating into neutrinos. Such a detector could have the ability to resolve the direction of the electron in a neutrino scattering event, and thus to infer information about the source direction for individual neutrino events. We consider the improvements on the expected experimental sensitivity that this directional information would provide. Even without directional information, we find a DUNE-like LArTPC detector is capable of setting limits on dark matter annihilation to neutrinos for dark matter masses above 30 MeV that are competitive with or exceed current experimental reach. While currently-demonstrated angular resolution for low-energy electrons is insufficient to allow any significant increase in sensitivity, these techniques could benefit from improvements to algorithms and the additional spatial information provided by novel 3D charge imaging approaches. We consider the impact of such enhancements to the resolution for electron directionality, and find that where electron-scattering events can be distinguished from charged-current neutrino interactions, limits on dark matter annihilation in the mass range where solar neutrino backgrounds dominate ($\lesssim 15$ MeV) can be significantly improved using directional information, and would be competitive with existing limits using $40$ kton$\times$year of exposure.