S.J. Barish

Comparison of jet size in νp interactions with that in e+e− annihilation

Abstract Using new ν p charged-current data from the Fermilab 15 foot hydrogen bubble chamber, some properties of the ν -induced hadronic jets are studied. The angular size of the jets is measured and compared with results from e + e − annihilation. The jets in the two processes are found to be quite similar in terms of the variables sphericity, thrust, and energy flow.

Study of the reaction νn→νpπ−

Abstract We have measured the excitation function for the neutral current process νn→νpπ− as a function of neutrino energy. Our data give a cross section ratio R=σ(νpπ−)/σ(μ−pπ+)=0.11±0.022 over the energy interval (0.3⩽E ν⩽1.5)GeV. This measurement of single-pion production in a kinematically defined reaction is the first to use a deuterium target. The R value, as well as other characteristics of the data, agrees with the Adler model for single-pion production via the neutral current and gives a value of sin2θw=0.26±0.09.

Inclusive ϱ0 production in νp charged-current interactions

Abstract Using data from the Fermilab 15 ft hydrogen bubble chamber, we have studied inclusive ϱ0 production in antineutrino-proton charged-current interactions. We measure (0.21 ± 0.03) ϱ0/event, corresponding to ϱ0/π−=0.12 ± 0.02. As a function of Q2 and for hadronic masses above a threshold region, the ϱ0/π− ratio shows little variation. At least 50% of the ϱ0s are consistent with coming from the current fragmentation region. The results agree reasonably well with the predictions of the quark fragmentation model of Feynman and field.

A test of quark fragmentation in the quark-parton model framework

Abstract The hadronic system produced in charged-current antineutrino interactions is used to study fragmentation of the d-quark. Some problems encountered in defining the current quark fragments are discussed. The properties of the fragmentation function are in good agreement with the expectations of the naive quark-parton model and, in particular, at the present level of statistics we find no need for either a Q 2 -or an x BJ -dependence.

Study of the reaction νp → μ+pπ−

Abstract We present data on the reaction ν p → μ + pπ − from an exposure of the Fermilab 15 ft hydrogen bubble chamber. The channel cross section for 5 GeV ν GeV and M( p π − ) GeV is σ = (27 ± 5) × 10 −40 cm 2 . This cross section is dominated by the I = 1 2 production amplitude.