Study of B to Pi L Nu and B to Rho L Nu Decays and Determination of
Study of B to Pi L Nu and B to Rho L Nu Decays and Determination of

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Published: 2011

Total Pages: 47

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We present an analysis of exclusive charmless semileptonic B-meson decays based on 377 million B{bar B} pairs recorded with the BABAR detector at the ? (4S) resonance. We select four event samples corresponding to the decay modes B° → ?−l+?, B+ → ?°l+?, B° → ?−l+?, and B+ → ?°l+?, and find the measured branching fractions to be consistent with isospin symmetry. Assuming isospin symmetry, we combine the two B → ?l? samples, and similarly the two B → ?l? samples, and measure the branching fractions ?(B° → ?−l+?) = (1.41 ± 0.05 ± 0.07) x 10−4 and ?(B° → ?°l+?) = (1.75 ± 0.15 ± 0.27) x 10−4, where the errors are statistical and systematic. We compare the measured distribution in q2, the momentum transfer squared, with predictions for the form factors from QCD calculations and determine the CKM matrix element.

Study of B to Pi Ell Nu and B to Rho Ell Nu Decays and Determination of
Study of B to Pi Ell Nu and B to Rho Ell Nu Decays and Determination of

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Published: 2005

Total Pages: 8

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We present an analysis of exclusive charmless semileptonic B-meson decays based on 83 million B{bar B} pairs recorded with the BABAR detector at the ?(4S) resonance. Using isospin symmetry, we measure branching fractions ?(B° → ?−l+?) = (1.38 ± 0.10 ± 0.16 ± 0.08) x 10−4 and ?(B° → ?−l+?) = (2.14 ± 0.21 ± 0.48 ± 0.28) x 10−4, where the errors are statistical, experimental systematic, and due to form-factor shape uncertainties. We compare the measured distribution in q2, the momentum-transfer squared, with theoretical predictions for the form factors from lattice QCD and light-cone sum rules, and extract the Cabibbo-Kobayashi-Maskawa (CKM) matrix element.

Study of the B to Xclnu Decays and Determination of
Study of the B to Xclnu Decays and Determination of

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Published: 2004

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We report studies of semileptonic decays, B → X{sub c}l[nu], based on a sample of 88 million B{bar B} 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.

Issues in General Physics Research: 2011 Edition
Issues in General Physics Research: 2011 Edition

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Publisher: ScholarlyEditions

Published: 2012-01-09

Total Pages: 8864

ISBN-13: 1464963282

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Issues in General Physics Research / 2011 Edition is a ScholarlyEditions™ eBook that delivers timely, authoritative, and comprehensive information about General Physics Research. The editors have built Issues in General Physics Research: 2011 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about General Physics Research in this eBook to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Issues in General Physics Research: 2011 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.

Study of Inclusive And Exclusive B ---] X/U L Nu Decays And the Measurement of
Study of Inclusive And Exclusive B ---] X/U L Nu Decays And the Measurement of

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Published: 2005

Total Pages: 5

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We report studies of B → X{sub u}l[nu] decays, based on a sample of 88 million B{bar B} events recorded with the BABAR detector. From both tagged and untagged B{bar B} events we have isolated inclusive charmless decays in kinematic regions for which the dominant background from B → X{sub c}l[nu] is reduced by making requirements on different variables: the electron energy E{sub l}, the momentum transfer q2, and the hadronic mass m{sub X}. Using theoretical calculations we extrapolate to the total decay rate to determine the CKM matrix element.

Reconstruction of B- --] D*° E- Nu Decays and Determination of |Vcb|
Reconstruction of B- --] D*° E- Nu Decays and Determination of |Vcb|

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Published: 2001

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In this analysis the decay B- --> D*° e- nu is measured. The underlying data sample consists of about 226 million B-meson pairs accumulated on the Y(4S) resonance by the BABAR detector at the asymmetric e+e- collider PEP II. The reconstruction of the decay uses the channels D*° --> D° pi°, D° --> K- pi+ and pi° --> gamma gamma. The neutrino is not reconstructed. Since the rest frame of the B meson is unknown, the boost w of the D*° meson in the B meson rest frame is estimated by w'. The w' spectrum of the data is described in terms of the partial decay width dGamma/dw given by theory and the detector simulation translating each spectrum dGamma/dw into an expectation of the measured w' spectrum. dGamma/dw depends on a form factor F(w) parameterizing the strong interaction in the decay process. To find the best descriptive dGamma/dw a fit to the data determines the following two parameters of dGamma/dw: (i) F(1)|Vcb|, the product between F at zero D*°-recoil and the Quark mixing parameter |Vcb|; (ii) rho^2, a parameter of the form factor F(w). The former parameter scales the height of dGamma/dw and rho^2 varies the shape of it. The determined values of F(1)|Vcb|, rho^2 and the branching fraction BF(B- --> D*° e- nu) are F(1)|Vcb| = (35.8 +- 0.5 +- 1.5) x 10e-03, rho^2 = (1.08 +- 0.05 +- 0.09) and BF(B- --> D*° e- nu) = (5.60 +- 0.08 +- 0.42)%, where the uncertainties are statistical and systematic, respectively. The value of BF(B- --> D*° e- nu) has been determined by an integration of dGamma/dw over the allowed w range using the fitted values of F(1)|Vcb| and rho^2.

Analysis of B 2![omega]l[nu] Decays With BaBar
Analysis of B 2![omega]l[nu] Decays With BaBar

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Published: 2006

Total Pages:

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As part of the BaBar project at SLAC to study the properties of B mesons, we have carried out a study of the exclusive charmless semileptonic decay mode B → [omega]l[nu], which can be used to determine the magnitude of the Cabbibo- Kobayashi-Maskawa matrix element Vub. Using simulated event samples, this study focuses on determining criteria on variables for selection of B → [omega]l[nu] signal and suppression of background from other types of BB events and continuum processes. In addition, we determine optimal cuts on variables to ensure a good neutrino reconstruction. With these selection cuts, we were able to achieve a signal-to-background ratio of 0.68 and a signal efficiency of the order of 1%. Applying these cuts to a sample of 83 million BB events recorded by BaBar in e+e- collisions at the (4S) resonance, we obtain a yield of 115 ± 19 B → [omega]l[nu] decays.