相关论文: A Measurement of Rb using a Double Tagging Method
The experimental results on the ratios of branching fractions $\mathcal{R}(D) = {\cal B}(\bar{B} \to D \tau^- \bar{\nu}_{\tau})/{\cal B}(\bar{B} \to D \ell^- \bar{\nu}_{\ell})$ and $\mathcal{R}(D^*) = {\cal B}(\bar{B} \to D^* \tau^-…
The following is an overview of the measurements of the CKM matrix elements V_cb and V_ub that are based on detailed studies of semileptonic B decays by the BABAR and Belle Collaborations and recent advances in QCD calculations. In…
This paper reports a study of B meson oscillations using hadronic Z^0 decays with two identified leptons, and updates a previous publication by including data collected in 1994. Decay times are reconstructed for each of the semileptonic B…
The decays $\bar{B} \rightarrow D^{(*)} \tau^- \bar{\nu}_\tau$ are good probes to new physics beyond the Standard Model. The ratios of branching fractions $R(D^{(*)}) \equiv \mathit{BF}(\bar{B} \rightarrow D^{(*)} \tau^- \bar{\nu}_\tau) /…
A technique is presented to measure the efficiency with which $c$-jets are mistagged as b-jets (mistagging efficiency) using $t\bar{t}$ events, where one of the $W$ bosons decays into an electron or muon and a neutrino and the other decays…
We report a measurement of the branching fraction ratios R(D(*)) of Bbar -> D(*) tau- nubar_tau relative to Bbar -> D()* l- nubar_l (where l = e or mu) using the full Belle data sample of 772 x 10^6 BBbar pairs collected at the Y(4S)…
A search for CP(T) violation is performed and the fractional difference between the $b$ and $\bar b$ hadron lifetimes is measured using reconstructed secondary vertices in inclusive B hadron decays culled from 3.1 million $Z^0 \to q \bar q$…
An event sample enriched in semileptonic decays of b hadrons is selected using an inclusive lepton selection from approximately 3.0 million hadronic Z^0 decays collected with the OPAL detector. This sample is used to investigate B meson…
At present, two outstanding discrepancies between experiment and the standard model are the measurements of the hadronic branching fractions $R_b$ and $R_c$. We note that an independent measurement of these branching fractions may be…
We measure the branching fraction of B- -> tau- nu_tau-bar using the full Upsilon(4S) data sample containing 772*10^6 BBbar pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. Events with BBbar pairs are…
Hadronic Z decay data taken with the ALEPH detector at LEP1 are used to measure the three-jet rate as well as moments of various event-shape variables. The ratios of the observables obtained from b-tagged events and from an inclusive sample…
We report a measurement of the ratios of branching fractions $\mathcal{R}(D^{(*)}) = {\cal B}(\bar{B} \to D^{(*)} \tau^- \bar{\nu}_{\tau})/{\cal B}(\bar{B} \to D^{(*)} \ell^- \bar{\nu}_{\ell})$ where $\ell$ denotes an electron or a muon.…
The branching ratios of the decay of the tau lepton to five charged hadrons have been measured with the OPAL detector at LEP using data collected between 1991 and 1995 at e+e- centre-of-mass energies close to the Z resonance. The branching…
We present a measurement of the ttbar production cross section using events with one charged lepton and jets from ppbar collisions at a center-of-mass energy of 1.96 TeV. A b-tagging algorithm based on the probability of displaced tracks…
The measurements of Rb = sigma(e+e- -> bb~)/sigma(e+e- -> qq~) and of the b quark forward-backward charge asymmetry, A^b_fb, at centre-of-mass energies above the Z pole are described. The measurement of Rb is performed at \root{s} between…
Using a sample of 3.3 million Upsilon(4S) -> BBbar events collected with the CLEO II detector at the Cornell Electron Storage Ring (CESR), we measure the branching fraction for B -> rho l nu, |V_ub|, and the partial rate (Delta Gamma) in…
A sample of Z decays containing b-flavoured hadrons is tagged using leptons, and events having precise proper time measurements are selected. These events are used to study Bs oscillations. using the lepton to tag the decay b-flavour and…
Jet flavor tagging plays a crucial role in the measurement of relative partial decay widths of $Z$ boson, denoted as $R_b$($R_c$), which is considered as a fundamental test of the Standard Model and sensitive probe to new physics. In this…
In hadronic decays of Z bosons recorded with the OPAL detector at LEP, events containing b quarks were selected using the long lifetime of b flavoured hadrons. Comparing the 3-jet rate in b events with that in d,u,s and c quark events, a…
We present a new measurement of the decay B- -> tau- nu_tau-bar with a semileptonic B tagging method, using a data sample containing 657*10^6 BB-bar pairs collected at the (4S) resonance with the Belle detector at the KEKB asymmetric e+e-…