Neville W. Reay

Observation of tau neutrino interactions

Abstract The DONUT experiment has analyzed 203 neutrino interactions recorded in nuclear emulsion targets. A decay search has found evidence of four tau neutrino interactions with an estimated background of 0.34 events. This number is consistent with the Standard Model expectation.The DONUT experiment has analyzed 203 neutrino interactions recorded in nuclear emulsion targets. A decay search has found evidence of four tau neutrino interactions with an estimated background of 0.34 events. This number is consistent with the Standard Model expectation.

A new upper limit for the tau-neutrino magnetic moment

Abstract Using a neutrino beam in which a ντ component was identified for the first time, the ντ magnetic moment was measured based on a search for an anomalous increase in the number of neutrino–electron interactions. One such event was observed when 2.3 were expected from background processes, giving an upper 90% confidence limit on μντ of 3.9×10−7μB.Using a prompt neutrino beam in which a nu_tau component was identified for the first time, the nu_tau magnetic moment was measured based on a search for an anomalous increase in the number of neutrino-electron interactions. One such event was observed when 2.3 were expected from background processes, giving an upper 90% confidence limit of 3.9x10^-7 Bohr magnetons.

Search for CP violation in charged D meson decays

Abstract We report results of a search for CP violation in the singly Cabibbo-suppressed decays D + → K − K + π + , φπ + , K ∗ (892) 0 K + , and π − π + π + based on data from the charm hadroproduction experiment E791 at Fermilab. We search for a difference in the D + and D − decay rates for each of the final states. No evidence for a difference is seen. The decay rate asymmetry parameters ( A CP ), defined as the difference in the D + and D − decay rates divided by the sum of the decay rates, are measured to be: A CP ( KKπ ) = −0.014±0.029, A CP ( φπ ) = −0.028±0.036, A CP (K ∗ (892)K) = −0.010±0.050 and A CP ( πππ ) = −0.017±0.042.We report results of a search for CP violation in the singly Cabibbosuppressed decays D → KKπ, φπ, K(892)0K+, and πππ based on data from the charm hadroproduction experiment E791 at Fermilab. We search for a difference in the D and D decay rates for each of the final states. No evidence for a difference is seen. The decay rate asymmetry parameters (ACP ), defined as the difference in the D + and D decay rates divided by the sum of the decay rates, are measured to be: ACP (KKπ) = −0.014 ± 0.029, ACP (φπ) = −0.028 ± 0.036, ACP (K(892)K) = −0.010 ± 0.050, and ACP (πππ) = −0.017 ± 0.042. PACS numbers: 11.30.Er, 12.15.Ji, 13.25.Ft, 14.40.Lb Typeset using REVTEX

Differential cross-sections, charge production asymmetry, and spin density matrix elements for D*+-(2010) produced in 500-GeV/c pi- nucleon interactions

Abstract We report differential cross sections for the production of D ∗± (2010) produced in 500xa0GeV/ c π − -nucleon interactions from experiment E791 at Fermilab, as functions of Feynman- x ( x F ) and transverse momentum squared ( p T 2 ). We also report the D ∗± charge asymmetry and spin-density matrix elements as functions of these variables. Investigation of the spin-density matrix elements shows no evidence of polarization. The average values of the spin alignment are 〈 η 〉=0.01±0.02 and −0.01±0.02 for leading and non-leading particles, respectively.We report differential cross sections for the production of D*(2010) produced in 500 GeV/c pi^- nucleon interactions from experiment E791 at Fermilab, as functions of Feynman-x (x_F) and transverse momentum squared (p_T^2). We also report the D* +/- charge asymmetry and spin-density matrix elements as functions of these variables. Investigation of the spin-density matrix elements shows no evidence of polarization. The average values of the spin alignment are eta= 0.01 +- 0.02 and -0.01 +- 0.02 for leading and non-leading particles, respectively.