Limits on $\nu_\mu(\bar{\nu}_\mu)\to\nu_\tau(\bar{\nu}_\tau)$ and $\nu_\mu(\bar{\nu}_\mu)\to\nu_e(\bar{\nu}_e)$ Oscillations from a Precision Measurement of Neutrino-Nucleon Neutral Current Interactions

Abstract

We present limits on $\nu_\mu(\bar{\nu}_\mu)\to\nu_\tau(\bar{\nu}_\tau)$ and $\nu_\mu(\bar{\nu}_\mu)\to\nu_e(\bar{\nu}_e)$ oscillations based on a study of inclusive $\nu N$ interactions performed using the CCFR massive coarse grained detector in the FNAL Tevatron Quadrupole Triplet neutrino beam. The sensitivity to oscillations is from the difference in the longitudinal energy deposition pattern of $\nu_\mu N$ versus $\nu_\tau N$ or $\nu_e N$ charged current interactions. The $\nu_\mu$ energies ranged from 30 to 500 GeV with a mean of 140 GeV. The minimum and maximum $\nu_\mu$ flight lengths are 0.9 km and 1.4 km respectively. For $\nu_\mu\to\nu_\tau$ oscillations, the lowest 90% confidence upper limit in $\sin^22\alpha$ of $2.7\times 10^{-3}$ is obtained at $\Delta m^2\sim50$~eV$^2$. This result is the most stringent limit to date for $25<\Delta m^2<90$ eV$^2$. For $\nu_\mu\to\nu_e$ oscillations, the lowest 90% confidence upper limit in $\sin^22\alpha$ of $1.9\times 10^{-3}$ is obtained at $\Delta m^2\sim350$~eV$^2$. This result is the most stringent limit to date for $250<\Delta m^2<450$ eV$^2$, and also excludes at 90% confidence much of the high $\Delta m^2$ region favored by the recent LSND observation.