Copyright ~1975-Present, HEPData | Powered by Invenio, funded by STFC, hosted and originally developed at CERN, supported and further developed at IPPP Durham.
We report on the first observation of open charm production in neutral current deep inelastic neutrino scattering as seen in the NuTeV detector at Fermilab. The production rate is shown to be consistent with a pure gluon-$% Z^{0}$ boson production model, and the observed level of charm production is used to determine the effective charm mass. As part of our analysis, we also obtain a new measurement for the proton-nucleon charm production cross section at $\sqrt{s}=38.8$ GeV.
Nuclear transparencies measured in exclusive incoherent ρ0 meson production from hydrogen, deuterium, carbon, calcium, and lead in muon-nucleus scattering are reported. The data were obtained with the E665 spectrometer using the Fermilab Tevatron muon beam with a mean beam energy of 470 GeV. Increases in the nuclear transparencies are observed as the virtuality of the photon increases, in qualitative agreement with the expectations of color transparency.
We detected 1–10 MeV neutrons at laboratory angles from 80° to 140° in coincidence with 470 GeV muons deep inelastically scattered from H, D, C, Ca, and Pb targets. The neutron energy spectrum for Pb can be fitted with two components with temperature parameters of 0.7 and 5.0 MeV. The average neutron multiplicity for 40<ν<400 GeV is about 5 for Pb, and less than 2 for Ca and C. These data are consistent with a process in which the emitted hadrons do not interact with the rest of the nucleus within distances smaller than the radius of Ca, but do interact within distances on the order of the radius of Pb in the measured kinematic range. For all targets the lack of high nuclear excitation is surprising.
We have measured muon-proton deep inelastic scattering in the range 0.4<q2<3.6 (GeV/c)2. The data are consistent with muon-electron universality, and if the ratio ρ=νW2(μ−p)νW2(e−p) is fitted with the form ρ=N(1+q2Λ2)−2, we obtain N=0.997±0.043 and Λ−2=+0.006±0.016 (GeV/c)2. This result establishes that |Λ|>~5.1 GeV/c with 95% confidence.
We present measured hadron energy distributions for the reactions ν(ν¯)+N→ν(ν¯)+hadrons at high energy, as well as for the similar charged-current interactions. Insofar as possible, the determination of these distributions avoids any a priori assumptions about either the neutral-current or the charged-current interactions. We further analyze the neutral-current distributions within the framework of specific models, particularly the scaling model, to obtain a positive-helicity component P=0.36±0.10, which lies between pure V−A and pure V or A, and a coupling strength of g0=0.31±0.03 relative to the charged-current interaction. These coupling parameters agree well with the predictions of the Weinberg-Salam model with sin2θW=0.33±0.07.
Copyright ~1975-Present, HEPData | Powered by Invenio, funded by STFC, hosted and originally developed at CERN, supported and further developed at IPPP Durham.