Andrey N. Kuzmin

Evidence for B{sup -{yields}{tau}-{nu}}{sub {tau}}with a semileptonic tagging method

We present a measurement of the decay B{sup -{yields}{tau}-{nu}}{sub {tau}}using a data sample containing 657x10{sup 6} BB pairs collected at the {Upsilon}(4S) resonance with the Belle detector at the KEKB asymmetric-energy e{sup +}e{sup -} collider. A sample of B{sup +}B{sup -} pairs are tagged by reconstructing one B{sup +} meson decaying semileptonically. We detect the B{sup -{yields}{tau}-{nu}}{sub {tau}}candidate in the recoil. We obtain a signal with a significance of 3.6 standard deviations including systematic uncertainties, and measure the branching fraction to be B(B{sup -{yields}{tau}-{nu}}{sub {tau}})=[1.54{sub -0.37}{sup +0.38}(stat){sub -0.31}{sup +0.29}(syst)]x10{sup -4}. This result confirms the evidence for B{sup -{yields}{tau}-{nu}}{sub {tau}}obtained in a previous Belle measurement that used a hadronic B tagging method.

Charm hadrons from fragmentation and B decays in e{sup +}e{sup -} annihilation at {radical}(s)=10.6 GeV

We present an analysis of charm quark fragmentation at 10.6 GeV, based on a data sample of 103 fb collected by the Belle detector at the KEKB accelerator. We consider fragmentation into the main charmed hadron ground states, namely DZ, DP, Ds and LC, as well as the excited states DSZ and DSP. The fragmentation functions are important to measure as they describe processes at a low energy scale, where calculations in perturbation theory lead to large uncertainties. Fragmentation functions can also be used as input distributions for Monte Carlo generators. Additionally, we determine the average number of these charmed hadrons produced per B decay at the Ys resonance and measure the distribution of their production angle in epem annihilation events and in B decays.