Leptonic B Decays at BaBar
Leptonic B Decays at BaBar

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Published: 2003

Total Pages: 4

ISBN-13:

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The authors present results on searches for the rare B decays B° → ll− (l = e or?) and B+ → K+?{bar?} in?(4S) decays. The data used in these analyses were collected with the BABAR detector at the PEP-II e+e− storage ring during the years 2000 and 2001. The B° → l+l− search was performed using an integrated luminosity of 54.4 fb−1 accumulated at the?(4S) resonance (about 60 million B{bar B} pairs) while the B+ → K+?{bar?} search was performed with 50.7 fb−1 (about 56 million B{bar B} pairs). Both analyses use an additional 6.4 fb−1 of data accumulated about 40 MeV below resonance. They see no evidence for a signal in either the B → l+l− or B → K+{nu}{bar {nu}} decay modes and set the following upper limits at the 90% CL:?(B° → e+e−)

Searches for Leptonic B Decays at BaBar
Searches for Leptonic B Decays at BaBar

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Published: 2012

Total Pages: 3

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Measurements of the branching fractions of purely leptonic decays of B-mesons translate into constraints in the plane of the charged Higgs mass versus tan? which are relatively insensitive to the particular theoretical model. Using the full BABAR dataset of 450 million B-decays we search for these decays. No significant signal is found in the decays into electrons or muons and we set upper limits on the branching fractions of the order of a 10−6 at 90% confidence level. We measure the branching fraction of B 2!?? to be (1.7 ± 0.6) x 10−4.

New Results on Leptonic B Meson Decays at BaBar
New Results on Leptonic B Meson Decays at BaBar

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Published: 2008

Total Pages: 6

ISBN-13:

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The 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.

Rare Radiative and Leptonic B Decays: Recent Results from BaBar and Belle
Rare Radiative and Leptonic B Decays: Recent Results from BaBar and Belle

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Published: 2003

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Recent BABAR and Belle results on rare B decays involving photons or lepton pairs are reviewed. New preliminary limits from both experiments for B[yields][rho][gamma] and B[sup 0][yields][Omega][gamma], and from BABAR for B[sup -][yields] K[sup -][nu][bar[nu]] and B[sup+][yields][tau][sup+][nu][sub[tau]] are presented. Also summarized from the past year are Belle measurements of B[yields] X[sub s][ell][sup+][ell][sup -] and B[sup 0][yields] K*[sub 2](1430)[sup 0][gamma], preliminary BABAR measurements of B[yields] X[sub s][gamma], and preliminary results from BABAR and Belle on B[yields] K[sup (*)][ell][sup+][ell][sup -]. No significant deviations from Standard Model predictions have yet been found.

Leptonic Decays at BABAR.
Leptonic Decays at BABAR.

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Published: 2007

Total Pages: 4

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We present recent results on leptonic B decays using data collected by the BaBar detector at the PEP-II asymmetric-energy e+e- collider at the Stanford Linear Accelerator Center. We report searches for the B → ?+? decay based on two statistically independent data samples.

Inclusive Semileptonic B Decays at BABAR.
Inclusive Semileptonic B Decays at BABAR.

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Published: 2004

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The authors report updates on two analyses of inclusive semileptonic B decays based on a dataset of 89 million B[bar B] events recorded with the BABAR detector at the [Upsilon](4S) resonance. Events are selected by fully reconstructing the decay of one B meson and identifying a charged lepton from the decay of the other [bar B] meson. IN the first analysis, the measurement of the first and second moment of the hadronic mass distribution in Cabibbo-favored [bar B] [yields] X[sub c][ell][bar [nu]] decays allows for the determination of the nonperturbative parameters [bar [Lambda]] and [lambda][sub 1] of Heavy Quark Effective Theory (HQET) and V[sub cb]. In the second analysis, the hadronic mass distribution is used to measure the inclusive charmless semileptonic branching fraction and to determine V[sub ub].

New BaBar Results on Rare Leptonic B Decays
New BaBar Results on Rare Leptonic B Decays

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Published: 2002

Total Pages: 7

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New preliminary BaBar results for rare leptonic decays B− → K−?{bar?} and B° → ll− are reported. Using data collected at the?(4S) with the BaBar detector, no evidence for a signal was found yielding the corresponding upper limits at the 90% confidence level:?(B− → K− {nu}{bar {nu}})

B Decays
B Decays

Author: Sheldon Stone

Publisher: World Scientific

Published: 1994

Total Pages: 676

ISBN-13: 9789810218362

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This 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.

Semileptonic B Decays at BABAR.
Semileptonic B Decays at BABAR.

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Published: 2004

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We present results on semileptonic B decays obtained with the BABAR detector. The large data set accumulated at the PEP-II asymmetric-energy B-Factory allows a new measurement technique, where the hadronic decay of one B meson is fully reconstructed and the semileptonic decay of the recoiling B meson is studied. Traditional analysis techniques of inclusive and exclusive B decays complement this approach with very high statistics data samples. These measurements play an important role in the tests of the description of CP violation in the Standard Model: The determinations of the Cabibbo-Kobayashi-Maskawa matrix elements V[sub cb] and V[sub ub] provide constraints on the unitarity of the CKM triangle. Furthermore, the experimental measurement of parameters of Heavy Quark Effective Theory test the consistency of the theoretical description of semileptonic B decays.