R. S. Galik

Branching fractions of τ Leptons to three charged Hadrons

From electron-positron collision data collected with the CLEO detector operating at Cornell Electron Storage Ring near sqrt[s]=10.6 GeV, improved measurements of the branching fractions for tau decays into three explicitly identified hadrons and a neutrino are presented as B(tau(-)-->pi(-)pi(+)pi(-)nu(tau))=(9.13+/-0.05+/-0.46)%, B(tau(-)-->K-pi(+)pi(-)nu(tau))=(3.84+/-0.14+/-0.38) x 10(-3), B(tau(-)-->K-K+pi(-)nu(tau))=(1.55+/-0.06+/-0.09) x 10(-3), and B(tau(-)-->K-K+K-nu(tau))<3.7 x 10(-5) at 90% C.L., where the uncertainties are statistical and systematic, respectively.

Measurement of the ηb(1S) mass and the branching fraction for Υ(3S)→γηb(1S)

We report evidence for the ground state of bottomonium, eta_b(1S), in the radiative decay Upsilon(3S) --> gamma eta_b in e^+e^- annihilation data taken with the CLEO III detector. Using 6 million Upsilon(3S) decays, and assuming Gamma(eta_b) = 10 MeV/c^2, we obtain B(Upsilon(3S) --> gamma eta_b) = (7.1 +- 1.8 +- 1.1) X 10^{-4}, where the first error is statistical and the second is systematic. The statistical significance is about 4 sigma. The mass is determined to be M(eta_b) = 9391.8 +- 6.6 +- 2.0 MeV/c^2, which corresponds to the hyperfine splitting Delta M_{hf}(1S)_b = 68.5 +- 6.6 +- 2.0 MeV/c^2. Using 9 million Upsilon(2S) decays, we place an upper limit on the corresponding Y(2S) decay, B(Y(2S) --> gamma eta_b) < 8.4 X 10^{-4} at 90 % confidence level.

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 search for exclusive penguin decays of B mesons

Abstract We have measured upper limits on branching fractions for rare exclusive decays of B mesons arising from one-loop diagrams in the standard model of electroweak interactions. We also obtain an upper limit for the lepton-number-violating decay B 0 → μ ± e ∓ .

Measurement of the isospin mass splitting Ξ+cΞ0c

Abstract Using the CLEO detector, we present a measurement of the mass of the charged charmed strange baryon Ξ + c and its neutral counterpart the Ξ 0 c . The Ξ + c is observed through its decay to Ξ - π + π + , and its mass is measured to be (2467±3±4) MeV. The isospin mass splitting of the Ξ c system is found to be M ( Ξ + c )- M ( Ξ 0 c )=(−5±4±1)MeV.

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 +}).

Measurement of γγ widths of charmonium states

Abstract Using the CLEO detector at the Cornell Electron Storage Ring, we have searched for two-photon production of charmonium in four-track final states. We have measured Γ γγ ( η c )=5.9 +2.1 −1.8 ±1.9 keV, and we have obtained 95% CL upper limits of Γ γγ ( X c 0 ) Γ γγ ( X c 2 )

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 Ds decay modes

Abstract Using the CLEO detector, we have measured the branching ratios for the exclusive decays of the D s + meson into K ∗0 K + , K 0 K + , and K ∗+ K 0 relative to the decay D s + →φπ + to be close to unity. We have also measured the mass diference between the D s + and D + meson to be 98.5±1.5 MeV/ c 2 .