No Arabic abstract
Using a data sample of 980 ${rm fb}^{-1}$ of $e^+e^-$ annihilation data taken with the Belle detector operating at the KEKB asymmetric-energy $e^+e^-$ collider, we report the results of a study of the decays of the $Omega_c^0$ charmed baryon into hadronic final states. We report the most precise measurements to date of the relative branching fractions of the $Omega_c^0$ into $Omega^-pi^+pi^0$, $Omega^-pi^+pi^-pi^+$, $Xi^-K^-pi^+pi^+$, and $Xi^0K^-pi^+$, as well as the first measurements of the branching fractions of the $Omega_c^0$ into $Xi^-bar{K}^0pi^+$, $Xi^0bar{K}^0$, and $Lambda bar{K}^0bar{K}^0$, all with respect to the $Omega^-pi^+$ decay. In addition, we investigate the resonant substructure of these modes. Finally, we present a limit on the branching fraction for the decay $Omega_c^0toSigma^+K^-K^-pi^+$.
We report a measurement of the lifetime of the $Omega_c^0$ baryon using proton-proton collision data at center-of-mass energies of 7 and 8~TeV, corresponding to an integrated luminosity of 3.0 fb$^{-1}$ collected by the LHCb experiment. The sample consists of about 1000 $Omega_b^-toOmega_c^0mu^-bar{ u}_{mu} X$ signal decays, where the $Omega_c^0$ baryon is detected in the $pK^-K^-pi^+$ final state and $X$ represents possible additional undetected particles in the decay. The $Omega_c^0$ lifetime is measured to be $tau_{Omega_c^0} = 268pm24pm10pm2$ fs, where the uncertainties are statistical, systematic, and from the uncertainty in the $D^+$ lifetime, respectively. This value is nearly four times larger than, and inconsistent with, the current world-average value.
A search for charmless four-body decays of $Lambda_{b}^{0}$ and $Xi_{b}^{0}$ baryons with a proton and three charged mesons (either kaons or pions) in the final state is performed. The data sample used was recorded in 2011 and 2012 with the LHCb experiment and corresponds to an integrated luminosity of 3 fb$^{-1}$. Six decay modes are observed, among which $Lambda_{b}^{0} to pK^{-}pi^{+}pi^{-}$, $Lambda_{b}^{0} to pK^{-}K^{+}K^{-}$, $Xi_{b}^{0} to pK^{-}pi^{+}pi^{-}$ and $Xi_{b}^{0} to pK^{-} pi^{+}K^{-}$ are established for the first time. Their branching fractions (including the ratio of hadronisation fractions in the case of the $Xi_{b}^{0}$ baryon) are determined relative to the $Lambda_{b}^{0} to Lambda_{c}^{+}pi^{-}$ decay.
Using $567rm{pb}^{-1}$ of $e^+e^-$ collisions recorded at $sqrt{s}=4.599rm{GeV}$ with the BESIII detector, we report first measurements of absolute hadronic branching fractions of Cabibbo-favored decays of the $Lambda_{c}^{+}$ baryon with a double-tag technique. A global least-square fitter is utilized to improve the measured precision. Among the measurements for twelve $Lambda_{c}^{+}$ decay modes, the branching fraction for $Lambda_{c}^{+} rightarrow pK^-pi^+$ is determined to be $(5.84pm0.27pm0.23)%$, where the first uncertainty is statistical and the second is systematic. In addition, the measurements of the branching fractions of the other eleven Cabbibo-favored hadronic decay modes are significantly improved.
The branching fractions of D_s meson decays serve to normalize many measurements of processes involving charm quarks. Using 298 /pb of e+ e- collisions recorded at a center of mass energy of 4.17 GeV, we determine absolute branching fractions for eight D_s decays with a double tag technique. In particular we determine the branching fraction B(D_s -> K- K+ pi+) = (5.50 +- 0.23 +- 0.16)%, where the uncertainties are statistical and systematic respectively. We also provide partial branching fractions for kinematic subsets of the K- K+ pi+ decay mode.
Using 482 pb$^{-1}$ of data taken at $sqrt{s}=4.009$ GeV, we measure the branching fractions of the decays of $D^{*0}$ into $D^0pi^0$ and $D^0gamma$ to be $BR(D^{*0} to D^0pi^0)=(65.5pm 0.8pm 0.5)%$ and $BR(D^{*0} to D^0gamma)=(34.5pm 0.8pm 0.5)%$ respectively, by assuming that the $D^{*0}$ decays only into these two modes. The ratio of the two branching fractions is $BR(D^{*0} to D^0pi^0)/BR(D^{*0} to D^0gamma) =1.90pm 0.07pm 0.05$, which is independent of the assumption made above. The first uncertainties are statistical and the second ones systematic. The precision is improved by a factor of three compared to the present world average values.