Professor Amanda Cooper-Sarkar

Abstract:

Evidence for a significant higher twist contribution to high z π^- production in antineutrino scattering is presented. In events with W>3 GeV and Q²>1 GeV² in our data, it accounts for (51 ±8)% of all π^- with z above 0.5. It is consistent with the z-Q² correlations of Berger's higher twist prediction. The data are inconclusive concerning the predicted y-z correlation and pT dependence. The z -Q² correlation is not adequately described by the Lund Monte-Carlo. © 1986 Springer-Verlag.

Abstract:

Observational upper limits on anomalous neutral-current events in a proton beam dump experiment are used to constrain the possible hadroproduction and decay of light gluinos. These results require ifmg̃ $ ̌4 GeV for ifmq̃ - minw. © 1985.

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 |Uøi|2, |Uei|2 < 10-6-10-7 are obtained for neutrino mass eigenstates vi 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 |Uøi|2 for neutrino masses greater than 0.5 GeV. For the mass eigenstate v3 in particular, we obtain the limits |Uø3|2 < 10-7-10-8, |Ue3|2 < 10-9-10-10 for the mass range 150-190 MeV, assuming the v3 to be produced directly in charmed F meson decays. © 1985.

Abstract:

A sample of over 25,000 fully measured neutrino and antineutrino charged current interactions in BEBC includes 192 dilepton candidates. The prompt signal after subtraction of background is 41 ±7μ+e-, 35±7μ+μ- events from {Mathematical expression} interactions, and 32±7μ-μ+ events from ν interactions. There are 2 trileptons, μ-μ-e+ and μ-μ-μ+. Results are compared with other experimental data and with the standard model. Limits to prompt like sign μ+e+, μ+μ+ and μ-μ- signals are given and compared with other experiments and with theoretical calculations. © 1985 Springer-Verlag.

Abstract:

Lambda hyperons from v p and {Mathematical expression}p charged current interactions have been analysed for polarization. A significant polarization is observed for Λ particles in the quasi-elastic region for both types of interactions. Part of this polarization is due to the decay of highly polarized Σ(1385) resonances. The results are compared with simple predictions of the quark parton model. © 1985 Springer-Verlag.