Extracting the Energy-Dependent Neutrino-Nucleon Cross Section Above 10 TeV Using IceCube Showers

TL;DR

This paper measures neutrino-nucleon cross sections at energies from 18 TeV to 2 PeV using IceCube data, confirming the predicted energy dependence and no signs of new physics up to 1 TeV center-of-mass energy.

Contribution

It provides the first measurement of the energy dependence of neutrino-nucleon cross sections above 18 TeV using IceCube data, confirming theoretical predictions.

Findings

Cross section increases with energy consistent with predictions

No evidence of new physics up to ~1 TeV center-of-mass energy

First measurement of neutrino interactions at these high energies

Abstract

Neutrinos are key to probing the deep structure of matter and the high-energy Universe. Yet, until recently, their interactions had only been measured at laboratory energies up to about 350 GeV. An opportunity to measure their interactions at higher energies opened up with the detection of high-energy neutrinos in IceCube, partially of astrophysical origin. Scattering off matter inside the Earth affects the distribution of their arrival directions --- from this, we extract the neutrino-nucleon cross section at energies from 18 TeV to 2 PeV, in four energy bins, in spite of uncertainties in the neutrino flux. Using six years of public IceCube High-Energy Starting Events, we explicitly show for the first time that the energy dependence of the cross section above 18 TeV agrees with the predicted softer-than-linear dependence, and reaffirm the absence of new physics that would make the cross section rise sharply, up to a center-of-mass energy of ~1 TeV.