10-17 July 2019
Ghent
Europe/Brussels timezone

Detection of a Neutrino Event at the Glashow Resonance Energy in IceCube

11 Jul 2019, 10:00
20m
Campus Ledeganck - Aud. 3 (Ghent)

Campus Ledeganck - Aud. 3

Ghent

Parallel talk Astroparticle Physics and Gravitational Waves Astroparticle Physics and Gravitational Waves

Speaker

Christian Haack (RWTH Aachen University)

Description

The IceCube Neutrino Observatory has measured the astrophysical neutrino flux from tens of TeV up to PeV energies, with no significant indication of a cutoff at the highest energies. At these energies, the neutrino event-rates quickly drop and spectral measurements are statistically limited.

However, at an energy of $\approx 6.3\,$PeV, anti-electron neutrinos are expected to resonantly interact with atomic electrons via the Glashow resonance mechanism creating $W^-$-bosons, and thereby increasing the total neutrino interaction probability by two orders of magnitude. This process has so far never been experimentally observed.

Observation of Glashow resonance events would provide a unique possibility to measure the ratio of neutrinos and anti-neutrinos, which is an important input for the theoretical modelling of astrophysical accelerators.

In this talk, I will present our finding of a single partially-contained shower-like neutrino event with deposited energy $E_\text{dep} = 6.04^{+0.63}_{-0.61}\,$PeV, consistent with a neutrino interacting via the Glashow resonance.

The event shows a clear signature of relativistic muon production, consistent with a hadronic origin of the particle shower. The leading muon energy is estimated to $E_\mu=20^{+44}_{-5}\,$GeV and consistent with expectations for a hadronic W-decay with $\approx 6\,$ PeV lab-energy.

Furthermore, such an event topology is highly unlikely to arise from atmospheric background. With an estimated background rate of $10^{-7}$ in the 4.6 year search period, this strongly suggests an astrophysical origin of the neutrino.

Primary authors

Christian Haack (RWTH Aachen University) Lu Lu (Chiba University) Tianlu Yuan (UW Madison)

Presentation Materials