Seminar Talk at CTP-SCU / 理论物理中心学术报告

Speaker: Dr. Jia Liu （刘佳 博士） (Johannes Gutenberg-University Mainz 德国美因茨大学)

Title: Boosted Dark Matter in IceCube and at the Galactic Center

Abstract:
We show that the event excess observed by the IceCube collaboration at TeV--PeV
energies, usually interpreted as evidence for astrophysical neutrinos, can be
explained alternatively by the scattering of highly boosted dark matter
particles. Specifically, we consider a scenario where a $\sim 4$~PeV scalar
dark matter particle $\phi$ can decay to a much lighter dark fermion $\chi$,
which in turn scatters off nuclei in the IceCube detector. Besides these
events, which are exclusively shower-like, the model also predicts a secondary
population of events at $\mathcal{O}(100\ \text{TeV})$ originating from the
3-body decay $\phi \to \chi \bar\chi a$, where $a$ is a pseudoscalar which
mediates dark matter--Standard Model interactions and whose decay products
include neutrinos.  This secondary population also includes track-like events,
and both populations together provide an excellent fit to the IceCube data.  We
then argue that a relic abundance of light Dark Matter particles $\chi$, which
may constitute a subdominant component of the Dark Matter in the Universe, can
have exactly the right properties to explain the observed excess in GeV gamma
rays from the galactic center region.

Time: 6/11 (Thu) 4:00pm 

Venue: Physics building 323, CTP-SCU