Probing Kaluza-Klein Dark Matter with Neutrino Telescopes

TL;DR

The paper investigates Kaluza-Klein dark matter in models with universal extra dimensions, where KK parity stabilizes the lightest KK particle (LKP). The LKP is the level-1 KK photon, essentially $B^1$, with a mass in the range $600$--$1200$ GeV that yields the observed relic density when radiative corrections and coannihilation are included, $\Omega_{B^1} h^2 \approx 0.16 \pm 0.04$. The authors compute the annihilation of $B^1$ dark matter in the Sun, predict high-energy neutrino fluxes, and translate these into IceCube event rates, finding a detectable signal of a few to tens of events per year for the favored mass range. Their analysis demonstrates a viable indirect detection channel for KK dark matter and informs neutrino telescope searches for new physics beyond the Standard Model.

Abstract

In models in which all of the Standard Model fields live in extra universal dimensions, the lightest Kaluza-Klein (KK) particle can be stable. Calculations of the one-loop radiative corrections to the masses of the KK modes suggest that the identity of the lightest KK particle (LKP) is mostly the first KK excitation of the hypercharge gauge boson. This LKP is a viable dark matter candidate with an ideal present-day relic abundance if its mass is moderately large, between 600 to 1200 GeV. Such weakly interacting dark matter particles are expected to become gravitationally trapped in large bodies, such as the Sun, and annihilate into neutrinos or other particles that decay into neutrinos. We calculate the annihilation rate, neutrino flux and the resulting event rate in present and future neutrino telescopes. The relatively large mass implies that the neutrino energy spectrum is expected to be well above the energy threshold of AMANDA and IceCube. We find that the event rate in IceCube is between a few to tens of events per year.