Measurement of the cross-section ratio sigma(sub n)/sigma(sub p) in inelastic muon-nucleon scattering at very low x and Q(sup 2)

摘要

Preliminary results are presented on the measurement of the cross-section ratio (sigma)(sub n)/(sigma)(sub p) inelastic (mu)N scattering obtained by the E-665 experiment using the Fermilab 490 GeV/c muon beam and liquid H(sub 2) and D(sub 2) targets. The results extend the previously measured x range by two orders of magnitude, down to 2 (times) 10(sup (minus)5), at Q(sup 2) > 10(sup (minus)2) GeV(sup 2)/C(sup 2). The ratio is consistent with 1 throughout the new range.