A measurement of R=sigma(L)/sigma(T) in deep inelastic neutrino-nucleon scattering at the Tevatron

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 GeV2. The new data provide the first measurements of R in the region x < 0.1. 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 the small-x region where R has not been previously measured, is in good agreement with the new CCFR data.