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.

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 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 B → πlv with Möbius Domain Wall Fermions

2018 ◽  
Vol 175 ◽  
pp. 13004 ◽  
Author(s):  
Brian Colquhoun ◽  
Shoji Hashimoto ◽  
Takashi Kaneko
Keyword(s):  
Domain Wall ◽  
Lattice Spacing ◽  
Semileptonic Decay ◽  
Form Factors ◽  
Heavy Quarks ◽  
Ckm Matrix ◽  
Domain Wall Fermions ◽  
Heavy Quark Mass ◽  
The Status

We report on the status of our calculation of the exclusive semileptonic decay, B → πlv; a key process in the determination of the CKM matrix element |Vub|. The Möbius domain wall action is used for both light and heavy quarks on gauge ensembles that include the effects of 2 + 1 flavours of quarks in the sea at three values of the lattice spacing: a ≈ 0.08 fm, a ≈ 0.055 fm, and a ≈ 0.044 fm. Pion masses go down to 300 MeV while heavy quarks masses are as large as 2.44mc. We present preliminary results of form factors from this process, showing dependence on momentum transfer, lattice spacing, and the heavy quark mass.

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|.

From factor ratio measurement in the decay Λc→Λ e+ ν

2001 ◽  
Vol 16 (supp01b) ◽  
pp. 511-513
Author(s):  
VICTOR PAVLUNIN ◽  
IAN SHIPSEY
Keyword(s):  
Matrix Element ◽  
Decay Rate ◽  
Form Factors ◽  
Systematic Errors ◽  
Ratio Measurement ◽  
Rate Distribution ◽  
Central Value ◽  
Cleo Collaboration ◽  
Factor Ratio ◽  
The Matrix

The hadronic current of the matrix element for the transition Λc→Λ e+ ν within the framework of HQET is parameterized in terms of two form factors. By studying the decay rate distribution in the space of the decay kinematic variables one can extract the ratio [Formula: see text] of the form factors. The first measurement1 of R was made by the CLEO collaboration in 1995. In this note we describe the study of the statistical and systematic errors for a 4.5 times larger data sample. The central value for R will be presented shortly.

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 A closer look at the extraction of |Vub| from B → πℓν

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Aritra Biswas ◽  
Soumitra Nandi ◽  
Sunando Kumar Patra ◽  
Ipsita Ray
Keyword(s):  
Matrix Element ◽  
Confidence Interval ◽  
Form Factors ◽  
Data Sets ◽  
Heavy Flavor ◽  
Comparable Group ◽  
Bayesian Approaches ◽  
Sum Rule ◽  
Ckm Matrix ◽  
Inclusive Decays

Abstract To extract the Cabibbo-Kobayashi-Maskawa (CKM) matrix element |Vub|, we have re-analyzed all the available inputs (data and theory) on the B → πℓν decays including the newly available inputs on the form-factors from light cone sum rule (LCSR) approach. We have reproduced and compared the results with the procedure taken up by the Heavy Flavor Averaging Group (HFLAV), while commenting on the effect of outliers on the fits. After removing the outliers and creating a comparable group of data-sets, we mention a few scenarios in the extraction of |Vub|. In all those scenarios, the extracted values of |Vub| are higher than that obtained by HFLAV. Our best results for |Vub|exc. are (3.94 ± 0.14) × 10−3 and $$ \left({3.93}_{-0.15}^{+0.14}\right) $$ 3.93 − 0.15 + 0.14 × 10−3 in frequentist and Bayesian approaches, respectively, which are consistent with that extracted from inclusive decays |Vub|inc. within 1 σ confidence interval.

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