Description
In pp collisions at the Large Hadron Collider (LHC), the far-forward tau (anti)neutrinos are produced predominantly from the $D_s^\pm$ decay and the subsequent tau decay. Theoretical predictions for the production of such tau (anti)neutrinos at LHC in collinear factorization rely on parton distribution functions (PDFs) in a combination of very small and large values of parton longitudinal momentum fraction $x$. We will present the flux of tau (anti)neutrinos produced in the forward direction of the LHC, obtained in a state-of-the-art computation which includes NLO QCD corrections to $D_s^\pm$ meson production. We will discuss the uncertainties arising from the PDFs as well as from the QCD scale choice, for which no univocal recipe exists. We will also provide an estimate of the expected number of events at the forthcoming neutrino experiments FASER_$\nu$ and SND@LHC, which will take data at the LHC during Run III, and at the experiments of a future recently proposed Forward Physics Facility, which could provide data capable of constraining NLO QCD evaluations.
