J. Kandaswamy

Branching fraction and photon energy spectrum for b → sγ

We have measured the branching fraction and photon energy spectrum for the radiative penguin process b-->s gamma. We find Beta(b-->s gamma) = (3.21+/-0.43+/-0.27(+0.18)(-0.10))x10(-4), where the errors are statistical, systematic, and from theory corrections. We obtain first and second moments of the photon energy spectrum above 2.0 GeV, = 2.346+/-0.032+/-0.011 GeV, and -(2) = 0.0226+/-0.0066+/-0.0020 GeV(2), where the errors are statistical and systematic. From the first moment, we obtain (in the modified minimal subtraction renormalization scheme, to order 1/M(3)(B) and beta(0)alpha(2)(s)) the heavy quark effective theory parameter Lambda = 0.35+/-0.08+/-0.10 GeV.

Hadronic mass moments in inclusive semileptonic B meson decays

We have measured the first and second moments of the hadronic mass-squared distribution in B-->X(c)l nu, for P(lepton)>1.5 GeV/c. We find = 0.251+/-0.066 GeV(2), <(M(2)(X)-)(2)> = 0.576+/-0.170 GeV(4), where M macro(D) is the spin-averaged D meson mass. From that first moment and the first moment of the photon energy spectrum in b-->s gamma, we find the heavy quark effective theory parameter lambda(1) (in the modified minimal subtraction renormalization scheme, to order 1/M(3)(B) and beta(0)alpha(2)(s)) to be -0.24+/-0.11 GeV(2). Using these first moments and the B semileptonic width, and assuming parton-hadron duality, we obtain absolute value of V(cb) = 0.0404+/-0.0013.

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.

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 +}).

Measurements of the decays tau(-) -> h(-)h(+)h(-)nu(tau) and tau(-) -> h(-)h(+)h(-)pi(0)nu(tau)

We use a data sample of 2.8 × 10 6 produced τ-pair events, obtained with the CLEO II detector, to measure B(τ - Ⅵh - h + h - (π 0 )ν τ ), where h refers to either a charged π or K. These branching fractions are measured with samples of lepton-tagged and 3 vs 3 events. We find B(τ - Ⅵh - h + h - ν τ )=0.0951±0.0007±0.0020 and B(τ - Ⅵh - h + h - π 0 ν τ )=0.0423±0.0006±0.0022. We also measure B(τ - Ⅵωh - ν τ )=0.0195±0.0007±0.0011.

Observation of the decay B-->FX.

We present evidence for inclusive F-italic-meson production in B-italic-meson decay. The product branching fraction B-italic(B-italic..-->..F-italicX-italic)B-italic(F-italic/sup +/..-->..phi..pi../sup +/) is measured to be 0.0038 +- 0.010. The F-italic momentum spectrum indicates the presence of a large component of two-body final states in the decay B-italic..-->..F-italicX-italic.

Charmonium decays to gamma pi(0), gamma eta, and gamma eta '

Using data acquired with the CLEO-c detector at the CESR e + e - collider, we measure branching fractions for J/ψ, ψ(2S), and ψ(3770) decays to γπ 0 γη, and γηʹ. Defining R n ≡ B[ψ(nS)→ γη]/B[ψ(nS) → γηʹ], we obtain R 1 = (21.1 ± 0.9)% and, unexpectedly, an order of magnitude smaller limit, R 2 < 1.8% at 90% C.L. We also use J/ψ→ γηʹ events to determine branching fractions of improved precision for the five most copious ηʹ decay modes.

Dalitz plot analysis of D(s)(+) -> K(+) K(-) pi(+)

We perform a Dalitz plot analysis of about 100,000 Ds+ decays to K+ K- pi+ and measure the complex amplitudes of the intermediate resonances which contribute to this decay mode. We also measure the relative branching fractions of Ds+ -->K+ K+ pi- and Ds+ -->K+ K+ K-. For this analysis we use a 384 fb-1 data sample, recorded by the BABAR detector at the PEP-II asymmetric-energy e+e- collider running at center-of-mass energies near 10.58 GeV.We perform a Dalitz plot analysis of about 100 000 Ds+ decays to K+K-π+ and measure the complex amplitudes of the intermediate resonances which contribute to this decay mode. We also measure the relative branching fractions of Ds+→K+K+π- and Ds+→K+K+K-. For this analysis we use a 384 fb-1 data sample, recorded by the BABAR detector at the PEP-II asymmetric-energy e+e- collider running at center-of-mass energies near 10.58 GeV.

Inclusive radiativeψ(2S)decays

Using e{sup +}e{sup -} collision data taken with the CLEO-c detector at the Cornell Electron Storage Ring, we have investigated the direct photon spectrum in the decay {psi}(2S){yields}{gamma}gg. We determine the ratio of the inclusive direct photon decay rate to that of the dominant three-gluon decay rate {psi}(2S){yields}ggg (R{sub {gamma}}{identical_to}{gamma}({gamma}gg)/{gamma}(ggg)) to be R{sub {gamma}}(z{sub {gamma}}>0.4)=0.070{+-}0.002{+-}0.019{+-}0.011, with z{sub {gamma}} defined as the scaled photon energy relative to the beam energy. The errors shown are statistical, systematic, and that due to the uncertainty in the input branching fractions used to extract the ratio, respectively.

Search forD0→p¯e+andD0→pe−

We search for simultaneous baryon and lepton number violating decays of the D 0 meson. Specifically, we use 281 pb ―1 of data taken on the ψ(3770) resonance with the CLEO-c detector at the CESR collider to look for decays D 0 → pe + , D 0 → pe + , D 0 → pe ― , and D 0 → pe ― . We find no significant signals and set the following branching fraction upper limits: D 0 → pe + (D 0 → pe + ) < 1.1 × 10 ―5 and D 0 → pe ― (D 0 → pe ― ) < 1.0 × 10 ―5 , both at the 90% confidence level.