Measurement of |Vcb| with $\bar{B}^0 \rightarrow D^{*+} \ell^- \bar{\nu}$ at CLEO

2001 ◽  
Vol 16 (supp01b) ◽  
pp. 639-641
Author(s):  
◽  
Daniel Cronin-Hennessy
Keyword(s):  
Form Factor ◽  
Matrix Element ◽  
Decay Rate ◽  
Branching Fraction ◽  
Ckm Matrix ◽  
Kinematic Point

We determine the CKM matrix element, |Vcb|, by measuring the differential decay rate of B→D*+ℓν as a function of w=vB · vD*. We extrapolate the decay rate to the kinematic point, w=1, where the form factor, ℱ(w), is accurately predicted by theory. We find ℱ(1)|Vcb|=0.0424±0.0018( stat. )±0.0019( syst. ). Integration of the differential decay rate, dΓ/dw, yields the B→D*+ℓν branching fraction, ℬ(B→D*+ℓν)=(5.66±0.29±0.33)%. The data are derived from 3.3 million [Formula: see text] events collected by the CLEO detector at CESR.

scholarly journals B → D*lv at non-zero recoil

2018 ◽  
Vol 175 ◽  
pp. 13003 ◽  
Author(s):  
Alejandro Vaquero Avilés-Casco ◽  
Carleton DeTar ◽  
Daping Du ◽  
Aida El-Khadra ◽  
Andreas Kronfeld ◽  
...  
Keyword(s):  
Matrix Element ◽  
Decay Rate ◽  
Form Factors ◽  
Heavy Quarks ◽  
Experimental Measurements ◽  
Ckm Matrix ◽  
Preliminary Results ◽  
Future Plans

We present preliminary results from our analysis of the form factors for the B → D*lv decay at non-zero recoil. Our analysis includes 15 MILC asqtad ensembles with Nf = 2 + 1 flavors of sea quarks and lattice spacings ranging from a ≈ 0.15 fm down to 0.045 fm. The valence light quarks employ the asqtad action, whereas the heavy quarks are treated using the Fermilab action. We conclude with a discussion of future plans and phenomenological implications. When combined with experimental measurements of the decay rate, our calculation will enable a determination of the CKM matrix element |Vcb|.

scholarly journals HFLAV $τ$ branching fractions fit and measurements of Vus with $τ$ lepton data

2019 ◽  
Author(s):  
Alberto Lusiani
Keyword(s):  
Matrix Element ◽  
Branching Fraction ◽  
Branching Fractions ◽  
Final States ◽  
Ckm Matrix ◽  
The Status ◽  
Global Fit

We report the status of the Heavy Flavour Averaging Group (HFLAV) averages of the \tauτ lepton measurements We then update the latest published HFLAV global fit of the \tauτ lepton branching fractions (Spring 2017) with recent results by . We use the fit results to update the Cabibbo-Kobayashi-Maskawa (CKM) matrix element \left|V_{us}\right||Vus| measurements with the \tauτ branching fractions. We combine the direct \tauτ branching fraction measurements with indirect predictions using kaon branching fractions measurements to improve the determination of \left|V_{us}\right||Vus| using \tauτ branching fractions. The \left|V_{us}\right||Vus| determinations based on the inclusive branching fraction of \tauτ to strange final states are about 3\sigma3σ lower than the \left|V_{us}\right||Vus| determination from the CKM matrix unitarity.

DETERMINATION OF |Vub| FROM TAGGED AND UNTAGGED $B \overline{B}$ EVENTS WITH THE BABAR DETECTOR

2005 ◽  
Vol 20 (16) ◽  
pp. 3707-3711
Author(s):  
◽  
JOCHEN DINGFELDER
Keyword(s):  
Matrix Element ◽  
Decay Rate ◽  
B Meson ◽  
Theoretical Models ◽  
Branching Ratios ◽  
High Signal ◽  
B Meson Decays ◽  
Ckm Matrix ◽  
Babar Detector

Measurements of charmless semileptonic B-meson decays and the CKM matrix element |Vub| are reported based on a sample of 88 million [Formula: see text] events recorded with the BABAR detector. Decays B → Xuℓν are selected from both tagged and untagged [Formula: see text] events and separated from the dominant charm background, B → Xcℓν, using different kinematic variables: the lepton momentum Eℓ, the squared four-momentum transfer q2, and the hadronic mass mX. The extrapolation to the total decay rate to determine |Vub| is performed for different theoretical models. We have also measured branching ratios for the exclusive semileptonic decays B → π(ρ,ω,η,η′,a0)ℓν, where a high signal purity is reached by fully or partially reconstructing the second B meson.

scholarly journals Study of the B → Xcℓν Decays and Determination of |Vcb|

2005 ◽  
Vol 20 (16) ◽  
pp. 3644-3647
Author(s):  
◽  
Vladimir Golubev
Keyword(s):  
Matrix Element ◽  
Heavy Quark ◽  
Electron Energy ◽  
Branching Fraction ◽  
Form Factors ◽  
Ckm Matrix ◽  
Mass Distributions ◽  
Babar Detector ◽  
Decay Form

We report studies of semileptonic decays, B → Xcℓν, based on a sample of 88 million [Formula: see text] events recorded with the BABAR detector. We have measured four moments of the electron energy and hadronic mass distributions and determined the inclusive branching fraction, the CKM matrix element |Vcb|, and other heavy quark parameters, using Heavy Quark Expansions in the kinetic mass scheme. In addition, we have studied a large sample of B0 → D*-ℓ+ν decays and extracted the decay form factors and |Vcb|.

scholarly journals DETERMINATION OF |Vcb| AND RELATED RESULTS FROM BABAR

2005 ◽  
Vol 20 (02n03) ◽  
pp. 557-560
Author(s):  
◽  
MASAHIRO MORII
Keyword(s):  
Matrix Element ◽  
Branching Fraction ◽  
Precise Determination ◽  
Ckm Matrix ◽  
Hadron Mass ◽  
Global Fit ◽  
Inclusive Semileptonic Decays ◽  
Babar Detector ◽  
Energy Moments

The CKM matrix element amplitude |Vcb| was determined using the data collected by the BABAR detector. The partial branching fraction, lepton-energy moments, and hadron-mass moments were measured in inclusive semileptonic decays B→Xcℓν. A global fit to a Heavy-Quark-Expansion calculation allowed precise determination of |Vcb|, mb, mc, ℬ(B→Xcℓν) and four non-perturbative parameters.

scholarly journals Padé-Improved Estimate of Perturbative Contributions to Inclusive Semileptonic b→u Decays

2001 ◽  
Vol 16 (supp01b) ◽  
pp. 642-644
Author(s):  
T. G. Steele ◽  
M. R. Ahmady ◽  
F. A. Chishtie ◽  
V. Elias
Keyword(s):  
Matrix Element ◽  
Decay Rate ◽  
Branching Ratio ◽  
Padé Approximant ◽  
Theoretical Uncertainty ◽  
Ckm Matrix ◽  
Pade Approximant

Padé-approximant methods are used to estimate the three loop perturbative contributions to the inclusive semileptonic b→u decay rate. These improved estimates of the decay rate reduce the theoretical uncertainty in the extraction of the CKM matrix element |Vub| from the measured inclusive semileptonic branching ratio.

scholarly journals K → μ+μ− as a clean probe of short-distance physics

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Avital Dery ◽  
Mitrajyoti Ghosh ◽  
Yuval Grossman ◽  
Stefan Schacht
Keyword(s):  
Matrix Element ◽  
Standard Model ◽  
Short Distance ◽  
Time Dependent ◽  
Final States ◽  
Interference Effects ◽  
Fundamental Theory ◽  
Long Distance ◽  
Ckm Matrix ◽  
The Standard Model

Abstract The K → μ+μ− decay is often considered to be uninformative of fundamental theory parameters since the decay is polluted by long-distance hadronic effects. We demonstrate that, using very mild assumptions and utilizing time-dependent interference effects, ℬ(KS → μ+μ−)ℓ=0 can be experimentally determined without the need to separate the ℓ = 0 and ℓ = 1 final states. This quantity is very clean theoretically and can be used to test the Standard Model. In particular, it can be used to extract the CKM matrix element combination $$ \mid {V}_{ts}{V}_{td}\sin \left(\beta +{\beta}_s\right)\mid \approx \mid {A}^2{\lambda}^5\overline{\eta}\mid $$ ∣ V ts V td sin β + β s ∣ ≈ ∣ A 2 λ 5 η ¯ ∣ with hadronic uncertainties below 1%.

scholarly journals Measurement of theD0→π−e+νedifferential decay branching fraction as a function ofq2and study of form factor parametrizations

2015 ◽  
Vol 91 (5) ◽  
Author(s):  
J. P. Lees ◽  
V. Poireau ◽  
V. Tisserand ◽  
E. Grauges ◽  
A. Palano ◽  
...  
Keyword(s):  
Form Factor ◽  
Branching Fraction
Sign in / Sign up

Export Citation Format

Share Document