W. Smart

LEFT-RIGHT ASYMMETRY IN NEUTRINO PRODUCED HADRON JETS

In an experiment (E546) to study interactions of {l angle}{ital E}{r angle}=100 GeV and {l angle}{ital Q}{sup 2}{r angle}=17 GeV{sup 2} neutrinos in the Fermilab 15-foot bubble chamber, we have looked for a left-right asymmetry in the azimuthal angle {phi} of individual hadrons about the direction of the lepton momentum transfer ({ital q} vector). Significant asymmetry is found for forward positive hadrons; for {ital x}{sub {ital F}}{gt}0.10, we find {l angle}cos{phi}{r angle}={minus}0.029{plus minus}0.008, where {ital x}{sub {ital F}} is the Feynman {ital x} variable. Negative hadrons with {ital x}{sub {ital F}}{gt}0.10 show no asymmetry, {l angle}cos{phi}{r angle}=0.004{plus minus}0.011. A model which includes parton intrinsic transverse momentum {ital k}{sub {ital t}} reproduces the asymmetry of combined positive and negative hadrons with {ital x}{sub {ital F}}{gt}0.10, {l angle}cos{phi}{r angle}={minus}0.018{plus minus}0.0065, if {l angle}{ital k}{sub {ital t}}{sup 2}{r angle}=0.065{plus minus}0.024 GeV{sup 2}/c{sup 2}. But the model predicts almost equal asymmetries for positive and negative hadrons. The model also agrees poorly with the observed dependence on the kinematic variables {ital x} and {ital Q}{sup 2} if the {ital k}{sub {ital t}} distribution is assumed to be independent of kinematic variables.

Limits on the Neutrino Oscillations Anti-muon Neutrino

In an exposure of the Fermilab 15-ft bubble chamber to the dichromatic antineutrino beam, 427 nu-bar/sub ..mu../ charged-current interactions were obtained. Taking advantage of the small and well understood background flux of nu-bar/sub e/s in the dichromatic nu-bar/sub ..mu../ beam, upper limits on the rates of antineutrino oscillations are obtained, with the precision limited by statistical rather than systematic errors, in contrast to previous experiments. The 90%-C.L. upper limits obtained for the average oscillation probabilities indicated are P(nu-bar/sub ..mu../..-->..nu-bar/sub e/) ..nu-bar/sub tau/)<4.4 x 10/sup -2/. The mean value of the distance from the neutrino-production point to the bubble chamber divided by the neutrino energy, , is 0.03 m/MeV.