The first search for extremely-high energy cosmogenic neutrinos with the IceCube Neutrino Observatory

TL;DR

This paper reports the first search for extremely-high energy cosmogenic neutrinos using the partially constructed IceCube detector, setting upper limits on neutrino fluxes in the energy range of 3×10^7 to 3×10^9 GeV based on 242.1 days of data.

Contribution

It presents the first search for EHE neutrinos with IceCube and provides model-independent upper limits on neutrino fluxes in the specified energy range.

Findings

No signal events detected in the data.

Established a 90% confidence level upper limit on neutrino flux.

Set constraints on models predicting EHE neutrino fluxes.

Abstract

We report on the results of the search for extremely-high energy (EHE) neutrinos with energies above $10^7$ GeV obtained with the partially ($\sim$30%) constructed IceCube in 2007. From the absence of signal events in the sample of 242.1 days of effective livetime, we derive a 90% C.L. model independent differential upper limit based on the number of signal events per energy decade at $E^2 \phi_{\nu_e+\nu_\mu+\nu_\tau}\simeq 1.4 \times 10^{-6}$ GeV cm$^{-2}$ sec$^{-1}$ sr$^{-1}$ for neutrinos in the energy range from $3\times10^7$ to $3\times10^9$ GeV.