Professor Amanda Cooper-Sarkar

Abstract:

A novel and efficient kinematic method is used to estimate the number of ντ charged current interactions with Eν > 20 GeV in the BEBC beam dump experiment. The result, -14±12 ντ events, is consistent with zero. The ratio of Ds to D meson production in 400 GeV proton interactions in copper is estimated to be below 0.65 at 90% c.l. The oscillation probability P(νe→ντ) averaged over the electron-(anti)neutrino spectrum is found to be below 18%. The hypothesis that νe and ντ are identical is excluded by about 6 standard deviations. A remarkable event is described: it contains a muon, a high pT photon and a high pT hadron. © 1987.

Abstract:

The prompt electron neutrino and muon neutrino fluxes from proton copper interactions at 400 GeV/c proton momentum have been measured. The asymmetry between the prompt electron (anti) neutrino and the prompt muon (anti) neutrino event rates above 20 GeV is Aeμ = (Ne - Nμ (Nc + Nμ) = 0.07 ± 0.08 corresponding to an Ne/Nμ ratio of 1.14-0.16-0.19. The cross section weighted charge asymmetry for electrons and muons combined is Aνν = 0.15 ± 0.08. The number of D decays into νe and νμ is (4.1 ± 0.9) × 10-4 per incident proton. No evidence for ντ interactions was found. © 1986.

Abstract:

BEBC filled in turn with hydrogen, and with a neon-hydrogen mixture, was exposed to the CERN SPS wide band neutrino and antineutrino beams. The ratios of the charged-current cross sections per nucleon, σ(νH2) σ(νNe) and σ(νH2) σ(νNe), between 20 and 300 GeV were found to be 0.656 ± 0.020 and 1.425 ± 0.052, respectively. Multiplying these ratios by the revised cross sections in neon, σ(νNe) E = (0.723 ± 0.038) × 10-38 cm2/GeV per nucleon and σ(νNe) E = (0.351 ± 0.019) × 10-38 cm2/GeV per nucleon, and their ratio, σ(νNe) σ(νNe) = 0.485 ± 0.020,, yields values for the total charged-current cross sections on protons, σ(νp)/E and σ(νp) E, of (0.474 ± 0.029) × 10-38 cm2/GeV and (0.500 ± 0.032) × 10-38 cm2/GeV. respectively, and a value for the ratio σ(νp) σ(νp) of 1.053 ± 0.066. © 1986.

Abstract:

The cross section for coherent production of a single π- meson in charged current antineutrino interactions on neon nuclei has been measured in BEBC to be (175±25) 10-40 cm2/neon nucleus, averaged over the energy spectrum of the antineutrino wide band beam at the CERN SPS; this corresponds to (0.9±0.1) % of the total charged current {Mathematical expression} cross section. The distributions of kinematical variables are in agreement with theoretical predictions based on the PCAC hypothesis and the meson dominance model; in particular, the Q2 dependence is well described by a propagator containing a mass m=(1.35±0.18) GeV. The absolute value of the cross section is also in agreement with the model. This analysis thus provides a test of the PCAC hypothesis in the antineutrino energy range 5-150 GeV. © 1986 Springer-Verlag.

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.