IC at IC: IceCube can constrain the intrinsic charm of the proton

TL;DR

This paper explores how IceCube neutrino observations can be used to constrain the intrinsic charm component in the proton's structure, which impacts atmospheric neutrino flux predictions.

Contribution

It estimates the atmospheric prompt neutrino flux from intrinsic charm and discusses how IceCube can constrain the proton's intrinsic charm content.

Findings

Intrinsic charm flux is comparable to non-intrinsic calculations after normalization.

IceCube can potentially constrain the intrinsic charm content in the proton.

Intrinsic charm affects high-energy atmospheric neutrino flux predictions.

Abstract

The discovery of extraterrestrial neutrinos in the $\sim$ 30 TeV -- PeV energy range by IceCube provides new constraints on high energy astrophysics. An important background to the signal are the prompt neutrinos which originate from the decay of charm hadrons produced by high energy cosmic-ray particles interacting in the Earth's atmosphere. It is conventional to use the calculations of charm hadroproduction using gluon splitting $g \to c \bar c$ alone. However, QCD predicts an additional "intrinsic" component of the heavy quark distribution which arises from diagrams where heavy quarks are multiply connected to the proton's valence quarks. We estimate the prompt neutrino spectrum due to intrinsic charm. We find that the atmospheric prompt neutrino flux from intrinsic charm is comparable to those calculated using QCD computations not including intrinsic charm, once we normalize the intrinsic charm differential cross sections to the ISR and the LEBC-MPS collaboration data. In future, IceCube will constrain the intrinsic charm content of the proton and will contribute to one of the major questions in high energy physics phenomenology.