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 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 Improvement of heavy-heavy current for calculation of B̅ → D(*)lv̅ form factors using Oktay-Kronfeld heavy quarks

2018 ◽  
Vol 175 ◽  
pp. 14010 ◽  
Author(s):  
Jon A. Bailey ◽  
Yong-Chull Jang ◽  
Weonjong Lee ◽  
Jaehoon Leem
Keyword(s):  
Matrix Element ◽  
Lattice Qcd ◽  
Heavy Quark ◽  
Recent Progress ◽  
Form Factors ◽  
Heavy Quarks ◽  
Power Counting ◽  
Ckm Matrix ◽  
Combining Data ◽  
Discretization Errors

The CKM matrix element |Vcb| can be extracted by combining data from experiments with lattice QCD results for the semileptonic form factors for the B̅ → D(*)lv̅ decays. The Oktay-Kronfeld (OK) action was designed to reduce heavy-quark discretization errors to below 1%, or through O(λ3) in HQET power counting. Here we describe recent progress on bottom-to-charm currents improved to the same order in HQET as the OK action, and correct formerly reported results of our matching calculations, in which the operator basis was incomplete.

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 Determination of the form factors for the decayB0→D*−l+νland of the CKM matrix element|Vcb|

2008 ◽  
Vol 77 (3) ◽  
Author(s):  
B. Aubert ◽  
M. Bona ◽  
D. Boutigny ◽  
Y. Karyotakis ◽  
J. P. Lees ◽  
...  
Keyword(s):  
Matrix Element ◽  
Form Factors ◽  
Ckm Matrix

scholarly journals Measurement of the form factors of the decayB0→D*−ℓ+νℓand determination of the CKM matrix element|Vcb|

2010 ◽  
Vol 82 (11) ◽  
Author(s):  
W. Dungel ◽  
C. Schwanda ◽  
I. Adachi ◽  
H. Aihara ◽  
T. Aushev ◽  
...  
Keyword(s):  
Matrix Element ◽  
Form Factors ◽  
Ckm Matrix

scholarly journals FLAG Review 2019

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
S. Aoki ◽  
Y. Aoki ◽  
D. Bečirević ◽  
T. Blum ◽  
G. Colangelo ◽  
...  
Keyword(s):  
Heavy Quark ◽  
Particle Physics ◽  
Light Quark ◽  
Form Factors ◽  
Matrix Elements ◽  
Ckm Matrix ◽  
Quark Masses ◽  
The Status ◽  
Ckm Matrix Elements

Abstract We review lattice results related to pion, kaon, D-meson, B-meson, and nucleon physics with the aim of making them easily accessible to the nuclear and particle physics communities. More specifically, we report on the determination of the light-quark masses, the form factor $$f_+(0)$$f+(0) arising in the semileptonic $$K \rightarrow \pi $$K→π transition at zero momentum transfer, as well as the decay constant ratio $$f_K/f_\pi $$fK/fπ and its consequences for the CKM matrix elements $$V_{us}$$Vus and $$V_{ud}$$Vud. Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of $$SU(2)_L\times SU(2)_R$$SU(2)L×SU(2)R and $$SU(3)_L\times SU(3)_R$$SU(3)L×SU(3)R Chiral Perturbation Theory. We review the determination of the $$B_K$$BK parameter of neutral kaon mixing as well as the additional four B parameters that arise in theories of physics beyond the Standard Model. For the heavy-quark sector, we provide results for $$m_c$$mc and $$m_b$$mb as well as those for D- and B-meson decay constants, form factors, and mixing parameters. These are the heavy-quark quantities most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. We review the status of lattice determinations of the strong coupling constant $$\alpha _s$$αs. Finally, in this review we have added a new section reviewing results for nucleon matrix elements of the axial, scalar and tensor bilinears, both isovector and flavor diagonal.

scholarly journals Bs → Kℓv form factors with 2+1 flavors

2018 ◽  
Vol 175 ◽  
pp. 13008 ◽  
Author(s):  
Yuzhi Liu ◽  
Jon A. Bailey ◽  
A. Bazavov ◽  
C. Bernard ◽  
C. M. Bouchard ◽  
...  
Keyword(s):  
Quark Mass ◽  
Strange Quark ◽  
Lattice Spacing ◽  
Light Quark ◽  
Form Factors ◽  
Ckm Matrix ◽  
Strange Quark Mass ◽  
Light Quark Mass ◽  
B Quark

Using the MILC 2+1 flavor asqtad quark action ensembles, we are calculating the form factors f0 and f+ for the semileptonic Bs → Kℓv decay. A total of six ensembles with lattice spacing from ≈ 0.12 to 0.06 fm are being used. At the coarsest and finest lattice spacings, the light quark mass m’l is one-tenth the strange quark mass m’s. At the intermediate lattice spacing, the ratio m’l/m’s ranges from 0.05 to 0.2. The valence b quark is treated using the Sheikholeslami-Wohlert Wilson-clover action with the Fermilab interpretation. The other valence quarks use the asqtad action. When combined with (future) measurements from the LHCb and Belle II experiments, these calculations will provide an alternate determination of the CKM matrix element |Vub|.

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.

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