scholarly journals CLEO RESULTS: B DECAYS

2002 ◽  
Vol 17 (22) ◽  
pp. 2951-2966 ◽  
Author(s):  
DAVID G. CASSEL
Keyword(s):  
Branching Fraction ◽  
Threshold Region ◽  
Matrix Elements ◽  
B Decays ◽  
Major Step ◽  
Model Calculations ◽  
Ckm Matrix ◽  
Cleo Collaboration ◽  
First Results ◽  
Photon Energy Spectrum

Measurements of many Standard Model constants are clouded by uncertainties in nonperturbative QCD parameters that relate measurable quantities to the underlying parton-level processes. Generally these QCD parameters have been obtained from model calculations with large uncertainties that are difficult to quantify. The CLEO Collaboration has taken a major step towards reducing these uncertainties in determining the CKM matrix elements |Vcb| and |Vub| using new measurements of the branching fraction and photon energy spectrum of b → s γ decays. This report includes: the new CLEO measurements of b → s γ decays, |Vcb|, and |Vub|; the first results from CLEO III data - studies of B → Kπ, ππ, and [Formula: see text] decays; mention of some other recent CLEO B decay results; and plans for operating CESR and CLEO in the charm threshold region.

scholarly journals QUARK MIXING AND CP VIOLATION — THE CKM MATRIX

2006 ◽  
Vol 21 (08n09) ◽  
pp. 1724-1737 ◽  
Author(s):  
ULRICH NIERSTE
Keyword(s):  
Neutral Current ◽  
New Physics ◽  
Tree Level ◽  
B Decays ◽  
Ckm Matrix ◽  
Penguin Decays ◽  
The Status ◽  
First Results ◽  
Global Fit

I summarize the theoretical progress in the determination of the CKM elements since Lepton-Photon 2003 and present the status of the elements and parameters of the Cabibbo-Kobayashi-Maskawa (CKM) matrix. One finds |Vus| = 0.2227 ± 0.0017 from K and τ decays and |Vcb| = (41.6 ± 0.5) · 10-3 from inclusive semileptonic B decays. The unitarity triangle can now be determined from tree-level quantities alone and the result agrees well with the global fit including flavour-changing neutral current (FCNC) processes, which are sensitive to new physics. From the global fit one finds the three CKM angles θ12 = 12.9° ± 0.1°, θ23 = 2.38° ± 0.03° and θ13 = 0.223° ± 0.007° in the standard PDG convention. The CP phase equals [Formula: see text] at 1σ CL and [Formula: see text] at 2σ CL. A major progress are first results from fully unquenched lattice QCD computations for the hadronic quantities entering the UT fit. I further present the calculation of three-loop QCD corrections to the charm contribution in [Formula: see text] decays, which removes the last relevant theoretical uncertainty from the [Formula: see text] system. Finally I discuss mixing-induced CP asymmetries in [Formula: see text] penguin decays, whose naive average is below its Standard Model value by 3σ.

scholarly journals B DECAYS ON THE LATTICE AND RESULTS FOR PHENOMENOLOGY

2005 ◽  
Vol 20 (16) ◽  
pp. 3651-3653
Author(s):  
MATTHEW WINGATE ◽  
CHRISTINE DAVIES ◽  
ALAN GRAY ◽  
EMEL GULEZ ◽  
JUNKO SHIGEMITSU ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Form Factors ◽  
Matrix Elements ◽  
B Decays ◽  
Ckm Matrix ◽  
Decay Constants ◽  
Lattice Monte Carlo ◽  
Ckm Matrix Elements ◽  
Fermion Action

Lattice Monte Carlo simulations now include the effects of 2 light sea quarks and 1 strange sea quark through the use of an improved staggered fermion action. Consequently, results important to phenomenology are free of the approximate 10% errors inherent in the quenched approximation. This talk reports on calculations of the B and Bs, decay constants and B → πℓν form factors. Accurate determinations of these quantities will lead to tighter constraints on CKM matrix elements.

RECENT RESULTS FROM ARGUS

1993 ◽  
Vol 08 (07) ◽  
pp. 573-582 ◽  
Author(s):  
HENNING SCHRÖDER
Keyword(s):  
Standard Model ◽  
Storage Ring ◽  
Confidence Level ◽  
Fundamental Constants ◽  
Matrix Elements ◽  
B Decays ◽  
Ckm Matrix ◽  
Upper Limit ◽  
The Standard Model ◽  
Yukawa Sector

Using the ARGUS detector at the e+e− storage ring DORIS II at DESY new results on beauty and τ physics have been obtained. In particular, new measurements on fundamental constants in the Yukawa sector of the Standard Model are presented. These comprise measurements of CKM matrix elements from the study of B decays as well as determinations of properties of the τ lepton and its neutrino vτ. From semileptonic B decays ARGUS finds |Vcb|=0.050±0.008±0.007 and from [Formula: see text] mixing |Vtd|= 0.007±0.002. An analysis of the decay type τ−→π−π−π+ντ yields a τ mass of mτ=(1776.3±2.4±1.4) MeV/c2. This result also leads to an improvement of the upper limit on the [Formula: see text] at the 95% confidence level.

Study of Radiative B Decay

1997 ◽  
Vol 12 (36) ◽  
pp. 2749-2755 ◽  
Author(s):  
H. Routh ◽  
V. P. Gautam
Keyword(s):  
Decay Width ◽  
Decay Process ◽  
Matrix Elements ◽  
B Decays ◽  
Ckm Matrix ◽  
Flavor Changing ◽  
Weak Annihilation ◽  
Ckm Matrix Elements ◽  
Inclusive Decay

Radiative B decays provide valuable information on some poorly known CKM matrix elements |Vtb| and |Vts|. So in our letter we propose to study the flavor changing radiative B decays corresponding to the inclusive b→ sγ and b→dγ decays. In this letter we discuss the radiative flavor changing B→ K**γ, Bs→ϕ;γ and the rare Bc→D*γ decays taking into account both the Penguin as well as weak annihilation contribution and it is found that weak annihilation contribution is negligible in case of decay of mesons consisting of light spectator, i.e. for B→K**γ and Bs→ϕ;γ but in case of decay of Bc→D*γ, weak annihilation contribution is the most dominating factor. It is also interesting to note that all the B→ K**γ, Bs→ϕ;γ and Bc→ D*γ decays have almost the same decay width because they have the same type of inclusive decay process b→ s(d)γ.

Inclusive semileptonic B decays and |Vcb|: In memoriam Kolya Uraltsev

2015 ◽  
Vol 30 (10) ◽  
pp. 1543002 ◽  
Author(s):  
Paolo Gambino
Keyword(s):  
Present Status ◽  
Matrix Elements ◽  
B Decays ◽  
Ckm Matrix ◽  
Model Independent ◽  
In Memoriam ◽  
Ckm Matrix Elements ◽  
Semileptonic B Decays

The CKM matrix elements |Vcb| can be extracted from inclusive semileptonic B decays in a model independent way pioneered by Kolya Uraltsev and collaborators. I review here the present status and latest developments in this field.

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