Neutrino Charm Production and a Limit to Neutrino Oscillations

Abstract

The production of charmed particles and a limit to tau lepton production have been measured using a hybrid emulsion spectrometer in the Fermilab wide-band neutrino beam. The relative cross section for charged current charmed particle production is $\sigma(\nu\to\mu^{-}c)/ \sigma (\nu\to\mu^{-}$)= 6.5 $\pm^{1.9}_{1.8}$%, and the energy dependence of the cross section and the kinematic distributions of the charm events are given. One event with charm pair production was observed. A limit of $\sigma(\nu\to\mu{c}\overline{c})/\sigma(\nu\to\mu{c}$)<0.06 (90%C.L.) is set to the ratio of charged current pair and single charm production. The relative rates of $D^{0}, D^{+}, F^{+}$, and $\Lambda^{+}_{C}$ production have been measured - the fraction of D mesons is $69\pm^{8}_{10}$%. Momentum, transverse momentum, Feynman X, and fragmentation (Z) distributions are presented. The mean Z for charmed hadron is 0.59$\pm$0.03($\pm$0.03). No tau leptons were observed, and an upper limit to the $\nu_{\mu} {-\tau}$" coupling of 0.0063 (90%C.L.) is set. For $\nu_{\mu} {-\nu}_{\tau}$ oscillations this implies $m^2_{\nu}$$_{\mu}$ $-m^2_{\nu}$$_{\tau}$<3.0 $ev^2$ for maximum mixing.