Neutrino scattering in a modified GIM model

Neutral- and charged-current neutrino- and antineutrino-nucleon scatterings are analyzed within the GIM picture by accounting for the rather pronounced scaling violations in the wee x region and utilizing a parameter xi = sup(1/2)/k. For x >> xi the naive parton model is assumed to apply, whereas for x approximately equal or < xi a diminution of free-parton vs. other scattering is expected. (x and y are the usual scaling variables, k is the c.m. momentum and sup(1/2) is the r.m.s. parton transverse momentum approximately equal to 0.3 GeV). In the model, an increasing number of sea quarks is freed as the energy E increases and the wee x domain recedes towards x = 0. The ratio σsub(c)sup(#betta#-barN)/σsub(c)sup(#betta#N), sub(c)sup(#betta#-bar), inclusive dσsub(c)/dy distributions for #betta#N and #betta#-barN scatterings, neutral-to-charged-current cross-section ratios Rsub(#betta#) and Rsub(#betta#-bar), as well as #betta#- and #betta#-bar-induced dilepton and accompanying strange-particle production are calculated, leading to satisfactory agreement with experiment from 10 GeV to 150 GeV. In particular, the model implies that Rsub(#betta#-bar)(E) remains relatively flat as E increases through the region where σsub(c)sup(#betta#-barN)/E appears to rise. Neutral-current processes are calculated by using the charged-current-determined model parameters within the Weinberg-Salam framework with sin2THETAsub(w) = 0.3. Comparison with dimuon experiments leads to semi-muonic branching ratios for the decay of charm in the range 5% to 10%, if one assumes a SU3-invariant sea. The calculated mean number of strange particles per neutrino-induced dilepton event is 1.4. (author)