Search for U(1)${}_{L_{\hat{I}}¼-L_{\ddot{I}}„}$ charged Dark Matter with neutrino telescope

Abstract

We study a simple Dirac fermion dark matter model in U(1)${}_{L_{\hat{I}}¼-L_{\ddot{I}}„}$ theory. The new light gauge boson $X$ plays important roles in both dark matter physics and the explanation for the muon $g-2$ anomaly. The observed dark matter relic density is realized by a large U(1)${}_{L_{\hat{I}}¼-L_{\ddot{I}}„}$ charge without introducing a resonance effect of the $X$ boson. As a by-product of the model, characteristic neutrino signatures from sub-GeV dark matter $\ddot{I}ˆ$ are predicted depending on the mass spectrum. We formulate the analysis of $\ddot{I}ˆ\bar{\ddot{I}}ˆ\to \hat{I}½\bar{\hat{I}}½$, and of $\ddot{I}ˆ\bar{\ddot{I}}ˆ\to XX$ followed by $X\to \hat{I}½\bar{\hat{I}}½$, in a model independent way. The energy spectrum of neutrinos in the former process is monochromatic while in the latter process is bowl-shape. We also evaluate sensitivity at Super-Kamiokande and future Hyper-Kamiokande detectors. The analysis is finally applied to the U(1)${}_{L_{\hat{I}}¼-L_{\ddot{I}}„}$ dark matter model.

32 pages, 6 figures; v2: added references and comments, corrected the neutrino spectrum from secluded annihilation and corresponding plots, conclusion unchanged, version to be published in JHEP