Predictions for high energy neutrino cross-sections from the ZEUS global PDF fits
Amanda Cooper-Sarkar, Subir Sarkar
TL;DR
The paper refines predictions for high-energy neutrino charged-current cross-sections by updating the ZEUS-S global PDF fits with complete HERA-I data and a robust treatment of PDF uncertainties, including correlated systematics, within the NLO DGLAP framework and a general-mass variable-flavour-number scheme for heavy quarks. By extending the kinematic range to $Q^2=10^{12}$ GeV$^2$ and $x=10^{-12}$, it provides updated cross-section predictions and highlights the regions of largest PDF uncertainty, particularly at low $Q^2$ and low $x$. The results indicate cross-sections are dominated by sea-quark contributions from gluon splitting at small $x$, with significant implications for neutrino telescope event rate estimates and potential signals of new QCD dynamics if measurements deviate from these predictions.
Abstract
We have updated predictions for high energy neutrino and antineutrino charged current cross-sections within the conventional DGLAP formalism of NLO QCD using a modern PDF fit to HERA data, which also accounts in a systematic way for PDF uncertainties deriving from both model uncertainties and from the experimental uncertainties of the input data sets. Furthermore the PDFs are determined using an improved treatment of heavy quark thresholds. A measurement of the neutrino cross-section much below these predictions would signal the need for extension of the conventional formalism as in BFKL resummation, or even gluon recombination effects as in the colour glass condensate model.