C. J. Stepaniak

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.

Search for baryons in the radiative penguin decay b→sγ

We have searched for the baryon-containing radiative penguin decays B^- -> \Lambda p-bar \gamma and B^- -> \Sigma^0 p-bar \gamma, using a sample of 9.7 million BBbar events collected at the \Upsilon(4S) with the CLEO detector. We find no evidence for either, and set 90% confidence level upper limits for photons with B rest frame energy greater than 2.0 GeV of [Br(B^- -> \Lambda p-bar \gamma) + 0.3 Br(B^- -> \Sigma^0 p-bar \gamma)] \Sigma^0 p-bar \gamma) + 0.4 Br(B^- -> \Lambda p-bar \gamma)] < 6.4 x 10^-6. From the latter, we estimate (for photons with B rest frame energy greater than 2.0 GeV) Br(B -> X_s \gamma, X_s containing baryons) s \gamma that are less than half the combined statistical and systematic errors quoted on these quantities.

Measurement of the charge asymmetry in B→K*: (892) ±π∓

We report on a search for a CP-violating asymmetry in the charmless hadronic decay B -> K*(892)+- pi-+, using 9.12 fb^-1 of integrated luminosity produced at \sqrt{s}=10.58 GeV and collected with the CLEO detector. We find A_{CP}(B -> K*(892)+- pi-+) = 0.26+0.33-0.34(stat.)+0.10-0.08(syst.), giving an allowed interval of [-0.31,0.78] at the 90% confidence level.

Search for B→p̄e-ν̄eX decay using a partial reconstruction method

Using data collected on the Upsilon(4S) resonance and the nearby continuum by the CLEO detector at the Cornell Electron Storage Ring, we have searched for the semileptonic decay of B mesons to electron-antiproton inclusive final states. We obtain an upper limit of B(B-> pbar e nuebar X) u decay, we find an upper limit of B(B^- -> p pbar e nuebar)< 5.2e-3. All upper limits are measured at the 90% confidence level.

Measurement of the Ξ c + lifetime

The Xi^+_c lifetime is measured using 9.0 fb^-1 of e+e- annihilation data collected on and just below the Upsilon(4S) resonance with the CLEO II.V detector at CESR. This is the first measurement of the Xi^+_c lifetime from a collider experiment. Using an unbinned maximum likelihood fit, the Xi^+_c lifetime is measured to be 503 +/- 47 (stat.) +/- 18 (syst.) fs. The precision of this measurement is comparable to previous measurements carried out by fixed target experiments with different sources of systematic uncertainties.

First observation of B̄ 0→ D* 0π +π +π -π -decays

We report on the observation of B0bar -> D*0 pi+ pi+ pi- pi- decays. The branching ratio is (0.30 +/- 0.07 +/- 0.06)%. Interest in this particular mode was sparked by Ligeti, Luke and Wise who propose it as a way to check the validity of factorization tests in B0bar -> D*+ pi+ pi- pi- pi0 decays.

Observation af the Omega(0)(c) charmed baryon at CLEO

The CLEO experiment at the CESR collider has used 13.7 fb(-1) of data to search for the production of the Omega(0)(c) (css ground state) in e(+)e(-) collisions at square root of (s) approximately 10.6 GeV. The modes used to study the Omega(0)(c) are Omega(-)pi(+), Omega(-)pi(+)pi(0), Xi-K-pi(+)pi(+), Xi0K-pi(+), and Omega(-)pi(+)pi(+)pi(-). We observe a signal of 40.4+/-9.0(stat) events at a mass of 2694.6+/-2.6(stat)+/-1.9(syst) MeV/c(2), for all modes combined.

Search for the decay B+→D*+Ks 0

We report on a search for the decay B+ -> D*+ K0_S and its charge conjugate with the CLEO detector at the Cornell Electron Storage Ring (CESR). No candidates are found in 9.10/fb of data. The background is estimated to be 0.29 +- 0.05 leading to an upper limit BF(B+ -> D*+ K0_S) = 9.5 x 10^{-5} (90% C.L.).