M. M. Mobayyen

Search for Heavy Neutrino Decays in the {BEBC} Beam Dump Experiment

Abstract New limits on lepton mixing parameters are derived from a search for decays of heavy neutrinos in a proton beam dump experiment. The limits | U oi | 2 , | U e i | 2 −6 −10 −7 are obtained for neutrino mass eigenstates v i of mass between 0.5 and 1.75 GeV, which can be produced through mixing in charmed D meson decays. This is the first such limit on | U o i | 2 for neutrino masses greater than 0.5 GeV. For the mass eigenstate v 3 in particular, we obtain the limits | U o 3 | 2 −7 −10 −8 , | U e 3 | 2 −9 −10 −10 for the mass range 150–190 MeV, assuming the v 3 to be produced directly in charmed F meson decays.

Measurement of the structure functions f

AbstractThe isoscalar nucleon structure functionsF2(x, Q2) andxF3(x, Q2) are measured in the range 0<Q2<64 GeV2, 1.7<W2<250 GeV2,x<0.7 using ν andn

and xf

bar v

and comparison with qcd predictions including kinematical and dynamical higher twist effects

n interactions on neon in BEBC. The data are used to evaluate possible higher twist contributions and to determine their impact on the evaluation of the QCD parameter Λ. In contrast to previous analyses reaching to such lowW2 values, it is found that a lown

Total cross sections νμ and ḡnμcharged-current interactions between 20 and 200 GeV

Lambda _{overline {MS} }

Strange Particle Production in Neutrino and Anti-neutrino Neon Interactions

n value in the neighbourhood of 100 MeV describes the data adequately and that the contribution of dynamical higher twist effects is small and negative.