[en] Using data collected on the Υ(4S) resonance and the nearby continuum by the CLEO-II detector, we have studied combinations of baryons with leptons produced in the process Υ(4S)→B bar B, B→lepton+X, bar B→baryon+X. Our results do not support models which Attribute the bulk of Λ_c production in bar B decay to the process b→cW^-,W^-→ bar cs. copyright 1997 The American Physical Society

[en] The decays Υ(4S)→BB , followed by B→D^*π and D^*→Dπ , permit reconstruction of all kinematic quantities that describe the sequence without reconstruction of the D , with reasonably low backgrounds. Using an integrated e⁺e^- luminosity of 3.1 fb^-1 accumulated at the Υ(4S) by the CLEO-II detector, we report measurements of B(B⁰→ D^*+π^-)=(2.81± 0.11±0.21±0.05)x10^-3 and B(B^-→D^*0π^-)=(4.34±0.33±0.34±0.1 8)x10^-3 . copyright 1998 The American Physical Society

[en] We have performed the first search for CP violation in tau lepton decay. CP violation in lepton decay does not occur in the minimal standard model but can occur in extensions such as the multi-Higgs doublet model. It appears as a characteristic difference between the τ^- and τ⁺ decay angular distributions for the semileptonic decay modes such as τ^-→K⁰π^-ν . We define an observable asymmetry to exploit this and find no evidence for any CP violation. copyright 1998 The American Physical Society

[en] Using data recorded by the CLEO-II detector at CESR, we report evidence of a pair of excited charmed baryons, one decaying into Λ⁺_cπ⁺ and the other into Λ⁺_cπ^-. The doubly charged state has a measured mass difference M(Λ⁺_cπ⁺) -M(Λ⁺_c) of 234.5±1.1±0.8 MeV/c² and a width of 17.9^+3.8_-3.2±4.0MeV/c², and the neutral state has a measured mass difference M(Λ⁺_cπ^-) -M(Λ⁺_c) of 232.6±1.0±0.8 MeV/c² and a width of 13.0^+3.7_-3.0±4.0MeV/c². We interpret these data as evidence of the Σ^*++_c and Σ^*0_c, the spin (3)/(2)⁺ excitations of the Σ_c baryons. copyright 1997 The American Physical Society

[en] A search for the lepton-family-number-violating decays τ→eγ and τ→μγ has been performed using CLEO II data. No evidence of a signal has been found and the corresponding upper limits are B(τ→eγ)<2.7x10^-6 and B(τ→μγ)<3.0x10^-6 at 90% C.L. copyright 1997 The American Physical Society

[en] We present new measurements of photon energies and branching fractions for the radiative transitions Υ(2S)→γχ_b(J=0,1,2)(1P). The masses of the χ_b states are determined from the measured radiative photon energies. The ratio of mass splittings between the χ_b substates, r≡(M_J=2-M_J=1)/(M_J=1-M_J=0), with M the χ_b mass, provides information on the nature of the b bar b confining potential. We find r(1P)=0.542±0.022±0.024. This value is somewhat lower than the previous world average, but more consistent with the theoretical expectation that r(1P)< r(2P); i.e., that this mass splitting ratio is smaller for the χ_b(1P) states than for the χ_b(2P) states. copyright 1999 The American Physical Society

[en] We have studied the decay bar B→Dl bar ν , where l=e or μ . From a fit to the differential decay rate dΓ/dw we measure the rate normalization F_D(1)[V_cb] and form factor slope ρ²_D , and, using measured values of τ_B , find Γ(bar B→Dl bar ν) = (12.0±0.9±2.1) ns^-1. The resulting branching fractions are B(bar B⁰→D⁺l^-bar ν)=(1.87±0.15± 0.32)% and B(B^-→D⁰ l^-bar ν)=(1.94±0.15±0.34)% . The form factor parameters are in agreement with those measured in bar B→D^*l bar ν decays, as predicted by heavy quark effective theory. copyright 1997 The American Physical Society

[en] The decay τ^-→2π^-π⁺ 3π⁰ν_τ has been studied with the CLEOII detector at the Cornell Electron Storage Ring. The branching fraction is measured to be (2.85±0.56±0.51)x10^-4 . The result is in good agreement with the isospin expectation but somewhat below the conserved-vector-current prediction. We have searched for resonance substructure in the decay. Within the statistical precision, the decay is saturated by the channels τ^-→π^-2π⁰ ων_τ , 2π^-π⁺ην_τ , and π^-2π⁰ην_τ . This is the first observation of this ω decay mode and the branching fraction is measured to be (1.89^+0.74_-0.67±0.40) x10^-4 . copyright 1997 The American Physical Society

[en] In a sample of 6.6x10⁶ produced B mesons we have observed decays B→η^'K , with branching fractions B(B⁺→η^' K⁺)=(6.5^+1.5_-1.4 ±0.9)x10^-5 and B(B⁰→η^' K⁰)=(4.7^+2.7_-2.0 ±0.9)x10^-5 . We have searched with comparable sensitivity for 17 related decays to final states containing an η or η^' meson accompanied by a single particle or low-lying resonance. Our upper limits for these constrain theoretical interpretations of the B→η^'K signal. copyright 1998 The American Physical Society

[en] We report the first observation of B→η^'X transitions with high momentum η^' mesons. We observe 39.0±11.6 B decay events with 2.0< p_η^'<2.7 GeV/c , the high momentum region where background from b→c processes is suppressed. We discuss the physical interpretation of the signal, including the possibility that it is due to b→sg^* transitions. Given that interpretation, we find B(B→η^'X_s )=[6.2±1.6(stat)± 1.3(syst)^+0.0_-1.5 (bkg)]x10^-4 for 2.0< p_η^'<2.7 GeV/c . copyright 1998 The American Physical Society