University of Rochester, Rochester, NY 14627, USA;California Institute of Technology, Pasadena, CA 91125, USA;University of Chicago, Chicago, IL 60637, USA;Fermilab, Batavia, IL 60510, USA;Stanford University, Stanford, CA 94305, USA
Abstract:
The rates for same-sign and opposite-sign dimuon events with missing energy (indicative of final-state neutrinos) have been measured in 278 GeV π?-Fe and 350 GeV proton-Fe collisions. The main source of opposite-sign events is two semi-leptonic decays of hadronically produced charm states. The same-sign events are consistent with background from pion and kaon decays. We obtain a limit of 0.044 (90% CL) on the fraction of D0 semileptonic decays that result in the wrong-sign muon and conclude that less than 9% (90% CL) of same-sign dimuon events produced in neutrino interactions can be attributed to D0-0 mixing. The data imply δm < 6.5 × 10?4 eV and for the difference in mass and inverse lifetime of the CP eigenstates of the D0. Limits on diffractive bottom production cross sections in proton and pion collisions are also presented.