We have measured parity-nonconserving optical rotation in the vicinity of the M1 absorption transition at 876 nm in bismuth. The result, R = Im(E1PNC/M1) = (-10.0 ± 1.0) centerdot 10-8, is in agreement with calculations based on the standard model of the electroweak interaction. The predicted form of the PNC rotation spectrum has been verified to high accuracy.
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The reaction $^2$H$(e,e^\prime p)n$ has been studied with full kinematic coverage for photon virtuality $1.75<Q^2<5.5$ GeV$^2$. Comparisons of experimental data with theory indicate that for very low values of neutron recoil momentum ($p_n<100$ MeV/c) the neutron is primarily a spectator and the reaction can be described by the plane-wave impulse approximation. For $100<p_n<750$ MeV/c proton-neutron rescattering dominates the cross section, while $\Delta$ production followed by the $N\Delta \to NN$ transition is the primary contribution at higher momenta.
Recoil neutron momentum distributions.
Recoil neutron angular distributions for neutron momenta in the range 400 to 600 MeV.
Recoil neutron angular distributions for neutron momenta in the range 200 to 300 MeV.
We have found 122 charmed-particle decays among 3855 neutrino interactions located in the fiducial volume of a hybrid emulsion spectrometer installed in the Fermilab wide-band neutrino beam. We obtain an average relative charmed-particle production cross section of σ(ν μ → c μ − ) σ(ν μ →μ − ) =4.9 −0.6 +0.7 % , at an average neutrino energy of 22 GeV. We also obtain a production rate of σ(ν μ → c c ν μ ) σ(ν μ →ν μ ) =0.13 −0.11 +0.31 % , if we assume that there was an undetected muon, a limit of σ(ν μ → c c μ − ) σ(ν μ → c μ − )<3% (90% CL ) can be obtained. Other cross section ratios and limits are also presented.
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