Extraction of R=sigma_L/sigma_T from CCFR Neutrino and Antinetrino Differential Cross Sections

TL;DR

This paper measures the ratio R=sigma_L/sigma_T from neutrino and antineutrino differential cross sections on iron, confirming previous results at high Q2 and providing first data at low x and Q2, with implications for QCD and nuclear effects.

Contribution

It presents the first measurements of R in the low x and Q2 < 1 GeV2 region, extending the understanding of nuclear effects in neutrino scattering.

Findings

R in neutrino scattering agrees with muon and electron scattering measurements.

Data at Q2 > 1 GeV2 align with NNLO QCD calculations using NNLO PDFs.

First measurements of R at low x and Q2 < 1 GeV2 show an anomalous rise observed by HERMES.

Abstract

We report on the extraction of R=sigam_L/sigma_T from CCFR neutrino and antineutrino-Iron differential cross sections. R as measured in neutrno scattering is in agreement with $R$ as measured in muon and electron scattering. All data on R for Q2 > 1 GeV2 are in agreement with a NNLO QCD calculation which uses NNLO PDFs and includes target mass effects. We report on the first measurements of R in the low x and Q2 < 1 GeV2 region (where an anomalous large rise in R for nuclear targets has been observed by the HERMES collaboration).