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Published: 2008
Total Pages: 6
ISBN-13:
DOWNLOAD EBOOKThe authors present selected new results on leptonic B meson decays from the BABAR experiment: searches for the decays B° → ll−, B+ → l+? and B° → l+?−, and B → K?{bar {nu}}, where l = e or?. They observe no evidence for these decays and set upper limits on their branching fractions.
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Published: 2012
Total Pages: 8
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DOWNLOAD EBOOKIn this note, recent results of studies of semileptonic B meson decays from BABAR are discussed and preliminary results given. In particular, a recent measurement of?(B → D{sup (*)}??) and the ratio?(B → D{sup (*)}??)/?(B → D{sup (*)}l?) is presented. For the D* mode, a branching fraction of 1.79 ± 0.13(stat) ± 0.17(syst) is found, with a ratio of 0.325 ± 0.023(stat) ± 0.027(syst). For the D mode, the results are 1.04 ± 0.12(stat) ± 0.14(syst) and 0.456 ± 0.053(stat) ± 0.056(syst), respectively. In addition, a study of B{sub s} production and semileptonic decays using data collected in a center-of-mass energy region above the?(4S) resonance is discussed. The semileptonic branching fraction?(B{sub s} → l?X) is measured to be 9.9{sub -2.1}{sup +2.6}(stat){sub -2.0}{sup +1.3}(syst).
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Published: 2011
Total Pages: 7
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DOWNLOAD EBOOKRadiative and leptonic decays of B-mesons represent an excellent laboratory for the search for New Physics. I present here recent results on radiative and leptonic decays from the Belle and BABAR collaborations. Radiative penguin and leptonic B-meson decays are excellent probes for investigating the effects of New Physics. Although current measurements are in agreement with the Standard Model expectations, they are still quite useful for setting bounds on possible NP models. The B → X{sub s}[gamma] and B → [tau][nu] measurements, for example, put strong constraints on the mass of charged Higgs bosons in Type II two-Higgs double models. The B → X{sub s}[gamma] branching fraction measurements also constrain models with universal extra dimensions.
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Published: 2011
Total Pages: 5
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DOWNLOAD EBOOKWe will present the most recent results on leptonic B decays B{sup {+-}(0)} 2!K*{sup {+-}(0)}[nu]{bar [nu]} and B{sup {+-}} 2![mu]{sup {+-}}{nu}, based on the data collected by the BaBar detector at PEP-II, an asymmetric ee− collider at the center of mass energy of the [Upsilon](4S) resonance. Rare B decays have always been a standard probe for New Physics (NP) searches. The very low Standard Model (SM) rate of these decays often make them unaccessible with the present experimental datasets, unless NP effects enhance the rate up to the current experimental sensitivity. Moreover, as NP effects can modify the decay kinematic, particular attention must be paid in order to perform a model independent analysis. A B-Factory provides an unique environment to investigate these processes. The high number of B{bar B} pairs produced by a B-Factory often allows to approach the needed experimental sensitivity. Moreover, the clean environment and the closed kinematic of the initial state enable to obtaining a very pure sample where to look for these decays.
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Published: 2013
Total Pages: 4
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Published: 2005
Total Pages:
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DOWNLOAD EBOOKThe authors present recent results on rare B meson decays based on data taken by the BABAR detector at the PEP-II asymmetric ee− collider. Included in this report are measurements of branching fractions and other quantities of interest for several hadronic, radiative, electroweak, and purely leptonic decays of B mesons.
Author: Sheldon Stone
Publisher: World Scientific
Published: 1994
Total Pages: 676
ISBN-13: 9789810218362
DOWNLOAD EBOOKThis 2nd edition is an extensive update of "B Decays?. The revisions are necessary because of the extensive amount of new data and new theoretical ideas. This book reviews what is known about b-quark decays and also looks at what can be learned in the future.The importance of this research area is increasing, as evidenced by the approval of the luminosity upgrade for CESR and the asymmetric B factories at SLAC and KEK, and the possibility of experiments at hadron colliders.The key experimental observations made thus far, measurement of the lifetimes of the different B species, B0-B0 mixing, the discovery of ?Penguin? mediated decays, and the extraction of the CKM matrix elements Vub and Vcb from semileptonic decays, as well as more mundane results, are described in great detail by the experimentalists who have been closely involved with making the measurements. Theoretical progress in understanding b-quark decays using HQET and lattice gauge techniques are described by theorists who have developed and used these techniques.Synthesizing the experimental and theoretical information, several articles discuss the implications for the ?Standard Model? and how further tests can be done using measurements of CP violation in the B system.
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Published: 2007
Total Pages: 359
ISBN-13:
DOWNLOAD EBOOKWe present the results of a search for four exclusive semileptonic decays B → D{sup (*)}[tau]−{bar [nu]}{sub [tau]} in 209 fb−1 of data collected with the BABAR detector, corresponding to 232 million e+e- → [Upsilon](4S) → B{bar B} events. We select events with a D{sup (*)} meson and a light lepton (e or [mu]) recoiling against a fully-reconstructed B meson. We perform a fit to the lepton spectrum and missing mass squared to discriminate signal events from backgrounds, predominantly B → D{sup (*)}{tau}−{bar [nu]}{sub {tau}}. A control sample of identified D**l−{bar {nu}}{sub {ell}} events is included in the fit to estimate the background contribution from these decays. We measure [beta](B → D{sub {tau}{nu}}) = (0.86±0.24±0.11±0.06)% and [beta](B → D*{sub {tau}{nu}}) = (1.62±0.31±0.10±0.05)%, where the errors are statistical, systematic, and normalization-mode related, respectively, and where the results are expressed for the {bar B}° lifetime.
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Published: 2011
Total Pages: 4
ISBN-13:
DOWNLOAD EBOOKThe authors present the most recent results on the leptonic B decays B 2!lv, B 2!lv[gamma], based on the data collected by the BABAR experiment at PEP-II, an asymmetric ee− collider at the center of mass energy of the [Upsilon](4S) resonance. Leptonic B decays are an excellent probe for new Physics, branching fraction measurements being complementary to the direct searches at high energy machines. Current experimental measurements are in agreement with Standard Model expectations, but, being already capable to constrain parameters of New Physics models today, they will be golden channels for the foreseen super flavor factories.
Author: Frank Juergen Tackmann
Publisher:
Published: 2008
Total Pages: 290
ISBN-13:
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