The prompt atmospheric neutrino flux in the light of LHCb

TL;DR

This paper predicts the atmospheric prompt neutrino flux at high energies using advanced QCD models constrained by LHCb data, reducing previous uncertainties and aligning better with IceCube observations.

Contribution

It provides a new, more accurate calculation of the prompt neutrino flux incorporating LHCb charm production data, improving upon previous models.

Findings

Prompt flux is about half of previous estimates.

Results are consistent with recent alternative predictions.

Uncertainty in flux estimates has been significantly reduced.

Abstract

The recent observation of very high energy cosmic neutrinos by IceCube heralds the beginning of neutrino astronomy. At these energies, the dominant background to the astrophysical signal is the flux of `prompt' neutrinos, arising from the decay of charmed mesons produced by cosmic ray collisions in the atmosphere. In this work we provide predictions for the prompt atmospheric neutrino flux in the framework of perturbative QCD, using state-of-the-art Monte Carlo event generators. Our calculation includes the constraints set by charm production measurements from the LHCb experiment at 7 TeV, and has been recently validated with the corresponding 13 TeV data. Our results for the prompt flux are a factor of about 2 below the previous benchmark calculation, in general agreement with two other recent estimates, and with an improved estimate of the uncertainty. This alleviates the existing tension between the theoretical prediction and IceCube limits, and suggests that a direct direction of the prompt flux is imminent.