Leptonic B Decays at BaBar
Leptonic B Decays at BaBar

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Published: 2003

Total Pages: 4

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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: 2011

Total Pages: 4

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The 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.

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

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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.

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}})

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].

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.