A Measurement of $R ={\sigma_L}/{\sigma_T}$ in Deep Inelastic Neutrino-Nucleon Scattering at the Tevatron

TL;DR

This paper reports the first measurements of the ratio R in deep inelastic neutrino-nucleon scattering at low x and a wide Q^2 range, confirming QCD predictions and expanding the understanding of nucleon structure.

Contribution

It provides the first measurements of R at x<0.1 in neutrino scattering, extending previous data and validating QCD-based models in this region.

Findings

R measured for 0.01<x<0.6 and 4<Q^2<300 GeV^2

Results agree with QCD fit predictions in small x region

First data on R in the low-x, high-Q^2 regime

Abstract

Measurements of neutrino-nucleon and antineutrino-nucleon differential cross sections using the CCFR neutrino detector at Fermilab have been used to extract preliminary values of $R ={\sigma_L}/{\sigma_T}$ in the kinematic region $0.01<x<0.6$, and $4<Q^2<300$ GeV$^2$. The new data provide the first measurements of $R$ in the $x<0.1$ region. The $x$ and $Q^2$ dependence of $R$ is compared with a QCD based fit to previous data. The QCD fit, which provides an estimate of $R$ in small $x$ region where $R$ has not been previously measured, is in good agreement with the new CCFR data.