Search for Sphalerons: IceCube vs. LHC

TL;DR

This paper investigates the potential to detect neutrino-induced sphaleron transitions with IceCube, comparing theoretical predictions to experimental data, and constraining the sphaleron rate based on IceCube and LHC results.

Contribution

It provides the first detailed calculation of sphaleron transition rates as a function of neutrino energy and compares these to IceCube data to set new constraints.

Findings

IceCube data constrains sphaleron rate at high barrier energies

Constraints are comparable to LHC limits from black hole searches

Potential for future LHC data to improve sensitivity to sphalerons

Abstract

We discuss the observability of neutrino-induced sphaleron transitions in the IceCube detector, encouraged by a recent paper by Tye and Wong (TW), which argued on the basis of a Bloch wave function in the periodic sphaleron potential that such transitions should be enhanced compared to most previous calculations. We calculate the dependence on neutrino energy of the sphaleron transition rate, comparing it to that for conventional neutrino interactions, and we discuss the observability of tau and multi-muon production in sphaleron-induced transitions. We use IceCube 4-year data to constrain the sphaleron rate, finding that it is comparable to the upper limit inferred previously from a recast of an ATLAS search for microscopic black holes at the LHC with $\sim 3$/fb of collisions at 13 TeV. The IceCube constraint is stronger for a sphaleron barrier height $E_{\rm Sph} \gtrsim 9$ TeV, and would be comparable with the prospective LHC sensitivity with 300/fb of data at 14 TeV if $E_{\rm Sph} \sim 11$ TeV.