Predictions for Neutrinos and New Physics from Forward Heavy Hadron Production at the LHC

TL;DR

This paper provides advanced QCD predictions for heavy hadron production at the LHC, crucial for neutrino flux estimates and new physics searches like ALPs, incorporating radiative corrections and small-x resummation.

Contribution

It introduces state-of-the-art QCD calculations for heavy hadron production, including radiative corrections and small-x resummation, and applies these to neutrino flux predictions and ALP sensitivity estimates.

Findings

Neutrino energy spectrum from charm hadron decays characterized.

First estimation of FASER's sensitivity to electrophilic ALPs.

Predictions match experimental data with improved accuracy.

Abstract

Scenarios with new physics particles feebly interacting with the Standard Model sector provide compelling candidates for dark matter searches. Geared with a set of new experiments for the detection of neutrinos and long-lived particles the Large Hadron Collider (LHC) has joined the hunt for these elusive states. On the theoretical side, this emerging physics program requires reliable estimates of the associated particle fluxes, in particular those arising from heavy hadron decays. In this work, we provide state-of-the-art QCD predictions for heavy hadron production including radiative corrections at next-to-leading order and using parton distribution functions including small-$x$ resummation at next-to-leading logarithmic accuracy. We match our predictions to parton showers to provide a realistic description of hadronisation effects. We demonstrate the utility of our predictions by presenting the energy spectrum of neutrinos from charm hadron decays. Furthermore, we employ our predictions to estimate, for the first time, FASER's sensitivity to electrophilic ALPs, which are predominantly generated in beauty hadron decays.