نتایج جستجو برای: b meson
تعداد نتایج: 908529 فیلتر نتایج به سال:
We present a measurement of the Standard Model CP violation parameter sin 2φ1 based on a 10.5 fb −1 data sample collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric e+e− collider. One neutral B meson is reconstructed in the J/ψKS , ψ(2S)KS , χc1KS , ηcKS , J/ψKL or J/ψπ0 CP -eigenstate decay channel and the flavor of the accompanying B meson is identified from its cha...
We summarise a Dyson-Schwinger-equation-based calculation of an extensive range of lightand heavy-meson observables, characterised by heavy-meson leptonic decays, semileptonic heavy-to-heavy and heavy-to-light transitions B → D, D, ρ, π; D → K, K, π, radiative and strong decays B (s) → B(s)γ; D (s) → D(s)γ, Dπ, and the rare B → Kγ flavour-changing neutral-current process. In the calculation the...
We present high-statistics results for neutral B-meson mixing and heavy-light-meson leptonic decays in the quenched approximation from tadpole-improved clover actions at β = 6.0 and β = 6.2. We consider quantities such as BBd(s) , fDd(s) , fBd(s) and the full ∆B = 2 matrix elements as well as the corresponding SU(3)-breaking ratios. These quantities are important for determining the CKM matrix ...
A(B → M1M2) ∝ φB ⊗H ⊗ φM1 ⊗ φM2 , (2) where ⊗ denotes the convolution over parton kinematic variables, the hard kernel H absorbs perturbative dynamics, and the B (M1, M2) meson distribution amplitude φB (φM1, φM2) absorbs nonperturbative dynamics in the B → M1M2 decay. A piece of contribution to B meson decays is factorizable, if it respects either Eq. (1) in the sense of the factorization assu...
The lifetimes of B + and B 0 mesons have been measured using a sample of 150,000 hadronic Z 0 decays collected by the SLD experiment at the SLC between 1993 and 1995. The analysis identiies the semileptonic decays of B mesons with high p; p t leptons and reconstructs the B meson decay length and charge by v ertexing the lepton with a partially reconstructed D meson. This method results in a sam...
Employing the light-cone sum rule approach in QCD, we relate the B-meson distribution amplitude to the B → π form factor at zero momentum transfer. In leading order, the sum rule is converted into a simple expression for the inverse moment λB of the distribution amplitude φ+. Using as an input the B → π form factor calculated from the light-cone sum rule in terms of pion distribution amplitudes...
With respect to large samples of Bc mesons expected to be produced at CERN Large Hadron Collider(LHC) and the large branching ratios Br(Bc → τ ν̄) and Br(Bc → μν̄), we suggest that Bc purely leptonic decays could offer an unique probe of the standard model and its extensions such as two Higgs doublet models and models involving supersymmetry, and also the structure of charged weak currents. PACS ...
We present high-statistics results for neutral B-meson mixing and heavy-light-meson leptonic decays in the quenched approximation from tadpole-improved clover actions at β = 6.0 and β = 6.2. We consider quantities such as BBd(s) , fDd(s) , fBd(s) and the full ∆B = 2 matrix elements as well as the corresponding SU(3)-breaking ratios. These quantities are important for determining the CKM matrix ...
We study the semileptonic branching fraction of B-meson into higher resonance of charmed meson D by using the Bjorken sum rule and the heavy quark effective theory(HQET). This sum rule and the current experiment of B-meson semileptonic decay into D and D predict that the branching ratio into Dlνl is about 1.7%. This predicted value is larger than the value obtained by the various theoretical ha...
(1) where GF is the Fermi constant, MD+ is theD + mass, ml the final state charged-lepton mass, and Vcd is a CKM matrix element, taken equal to Vus. Thus, in the SM measurement of purely leptonic decays allow a determination the decay constant, fD+ of the D + meson and similarly fDs of the D + s meson. Meson decay constants in the B system are used to translate measurements of BB̄ mixing to CKMm...
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