D. Perticone

Limits on rare exclusive decays of B mesons

Abstract We have set upper limits for rare exclusive decays of B mesons arising from higher order processes in the standard model of electroweak interactions. Such decays may occur via “penguin diagrams” in B decay. We also set an upper limit on a lepton-number-violating decay mode of the neutral B meson.

A measurement of the tau lifetime

The tau lepton lifetime is measured using four different methods with the DELPHI detector. Three measurements using one prong decays are combined, accounting for correlations, resulting in ττ=298 ±7 (stat.)±4 (syst.) fs while the decay length distribution of three prong decays gives ππ=298±13 (stat)±(syst.) fs. The combined result is ττ=298±7 fs. The ratio of the Fermi coupling constant from tau decay relative to that from muon decay is found to be 0.985±0.013, compatible with lepton universality.

Determination of B(Ds+) via observation of Ds+l+1/2

Using the CLEO detector at the Cornell Electron Storage Ring (CESR), we have determined the ratio {Gamma}({ital D}{sub {ital s}}{sup +}{r arrow}{phi}{ital l}{sup +}{nu})/{Gamma}({ital D}{sub {ital s}}{sup +} {r arrow}{phi}{pi}{sup +})=0.49{plus minus}0.10{sub {minus}0.14}{sup +0.10}. We use this measurement to derive {ital B}({ital D}{sub {ital s}}{sup +}{r arrow}{phi}{pi}{sup +}).

First observation of inclusive ψ production in ψ decays

The branching ratio for inclusive ψ production in ψ(1S) decays is measured to be (0.11 ± 0.04 ± 0.02)%.

Measurement of e+e-†bb forward-backward charge asymmetry between ss =52 and 57 GeV

Using 123 multihadronic inclusive muon-production {ital e}{sup +}{ital e}{sup {minus}} annihilation events at an average c.m. energy of 55.2 GeV, we extracted the forward-backward charge asymmetry of the {ital e}{sup +}{ital e}{sup {minus}}{r arrow}b{bar b} process and the {ital R} ratio for {ital b{bar b}} production. We used an analysis method in which the behavior of the {ital c} quark and lighter quarks is assumed, with only that of the {ital b} quark left indeterminate. The results, {ital A}{sub {ital b}}={minus}0.72{plus minus}0.28(stat){plus minus}0.13(syst) and {ital R}{sub {ital b}}=0.57{plus minus}0.16{plus minus}0.10, are consistent with the standard model.

Measurement of the D0, D+ and Ds+ meson lifetimes at √s = 10.58 GeV

Abstract We have measured the lifetimes of the D0, D+ and Ds+ mesons with data from the CLEO detector. We find τD0 = (5.0 ± 0.7 ± 0.4) × 10−13s, τD+ = (11.4 ± 1.6 ± 0.7) × 10−13s and τDs+ = (4.7 ± 2.2 ± 0.5) × 10−13s, giving lifetime ratios τD+/τD0 = 2.3 ± 0.5 and τDs+/τD0 = 0.9 ± 0.5.

Measurement of the [ital D][r arrow][pi][pi] branching fractions

Using data from CLEO II at the Cornell Electron Storage Ring we provide a new measurement of the branching fraction for [ital D][sup 0][r arrow][pi][sup +][pi][sup [minus]], and we present the first measurements of [ital D][sup 0][r arrow][pi][sup 0][pi][sup 0] and of [ital D][sup +][r arrow][pi][sup +][pi][sup 0], which is due to an isospin changing [Delta][ital I]=3/2 transition. From these data we extract the ratio of isospin amplitudes [vert bar][ital A][sub 2]/[ital A][sub 0][vert bar], and the cosine of the relative phase [delta]=[delta][sub 2][minus][delta][sub 0] between these amplitudes, for [ital D][r arrow][pi][pi] decays. Unlike the situation in kaon decay where [ital A][sub 2] is strongly suppressed, we find [vert bar][ital A][sub 2]/[ital A][sub 0][vert bar]=0.72[plus minus]0.13[plus minus]0.11 and cos[delta]=0.14[plus minus]0.13[plus minus]0.09.

D sub s sup + decays to. eta. rho. sup + ,. eta. prime. rho. sup + , and. phi. rho. sup +

We have observed the previously unseen {eta}{rho}{sup +} and {eta}{prime}{rho}{sup +} decay model of the {ital D}{sub {ital s}}{sup +}, and measured branching ratios relative to the {phi}{pi}{sup +} mode of 2.86{plus minus}0.38{sub {minus}0.38}{sup +0.36} and 3.44{plus minus}0.62{sub {minus}0.46}{sup +0.44}, respectively. In addition, the relative branching ratio for the decay into {phi}{rho}{sup +} is measured as 1.86{plus minus}0.26{sub {minus}0.40}{sup +0.29}. Combining these new measurements with previous results and those in the preceding Letter, we account for {approx}(79{plus minus}26)% of {ital D}{sub {ital s}} decays.

Ds+ decays to, +, and +

Using the CLEO II detector, we have accurately measured {ital D}{sub {ital s}} decay branching ratios relative to the {phi}{pi}{sup +} mode for the {eta}{pi}{sup +} and {eta}{prime}{pi}{sup +} states, for which there are conflicting claims; our results are 0.54{plus minus}0.09{plus minus}0.06 and 1.20{plus minus}0.15{plus minus}0.11, respectively.

D sub s sup + decays to. eta. pi. sup + and. eta. prime. pi. sup +

Using the CLEO II detector, we have accurately measured {ital D}{sub {ital s}} decay branching ratios relative to the {phi}{pi}{sup +} mode for the {eta}{pi}{sup +} and {eta}{prime}{pi}{sup +} states, for which there are conflicting claims; our results are 0.54{plus minus}0.09{plus minus}0.06 and 1.20{plus minus}0.15{plus minus}0.11, respectively.