Measurement of the Partial Branching Fraction for Inclusive Charmless Semileptonic B Decays and Extraction of
Measurement of the Partial Branching Fraction for Inclusive Charmless Semileptonic B Decays and Extraction of

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Publisher:

Published: 2005

Total Pages: 19

ISBN-13:

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Charmless semileptonic decays, {bar B} 2!X{sub u}l{bar {nu}}, are studied in a sample of 232 million B{bar B} decays recorded with the BABAR detector, in events where the decay of the second B meson is fully reconstructed. Inclusive charmless decays are selected in kinematic regions where the dominant background from semileptonic B decays to charm is reduced by requirements on the hadronic mass M{sub X} and the momentum transfer q2. The partial branching fraction for {bar B} 2!X{sub u}l{bar {nu}} decays for M{sub X} 1.7 GeV/c2 and q2 8 GeV2/c4 is measured to be [Delta][Beta]({bar b} 2!X{sub u}l{bar {nu}}) = (0.87 ± 0.09{sub stat} ± 0.09{sub sys} ± 0.01{sub th}) x 10−3. The CKM matrix element.

B Decays
B Decays

Author: Sheldon Stone

Publisher: World Scientific

Published: 1994

Total Pages: 676

ISBN-13: 9789810218973

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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.

Determination of [verticalV[sub Ub][vertical in Inclusive Semileptonic B Meson Decays
Determination of [verticalV[sub Ub][vertical in Inclusive Semileptonic B Meson Decays

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Published: 2004

Total Pages:

ISBN-13:

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The authors present a preliminary determination of the CKM matrix element V[sub ub] based on the analysis of semileptonic B decays from a sample of 88 million [Upsilon](4S) decays collected with the BaBar detector at the e[sup +]e[sup -] storage ring. Charmless semileptonic B decays are selected using the electron energy E-e and the invariant mass q[sup 2] of the electron-neutrino pair. The neutrino meomentum is inferred from a measurement of the visible energy and momentum in the detector and knowledge of the e[sup +]e[sup -] beam momenta. The partial branching fraction is determined in a region of the q[sup 2]-E-e plane where semileptonic B decays to charm are highly suppressed. The total charmless semileptonic branching fraction is extracted using a theoretical calculation based on the heavy quark expansion. Preliminary results yield V[sub ub] = (4.57 [+-] 0.21 [+-] 0.25 [+-] 0.34 + 0.59 - 0.29 [+-] 0.22) x 10[sup -3] where the uncertainties are from statistics (data and MC), detector modeling, background modeling, the shape function, and the heavy quark operator product expansion, respectively.

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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Publisher:

Published: 2011

Total Pages: 47

ISBN-13:

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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.

Charmless Hadronic B Decays at Belle and BaBar
Charmless Hadronic B Decays at Belle and BaBar

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Publisher:

Published: 2011

Total Pages: 4

ISBN-13:

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I report on recent measurements from the Belle and BABAR collaborations on the decay of the B meson to hadronic final states without a charm quark. The study of the branching fractions and angular distributions of B meson decays to hadronic final states without a charm quark probes the dynamics of both the weak and strong interactions, and plays an important role in understanding CP Violation (CPV) in the quark sector. CP Violation at the B factories is described graphically by a triangle with sides formed from the CKM matrix elements V{sub qd}V*{sub qb} (q = u, c, t) and internal angles [alpha], [beta] [gamma] (or [phi]2, [phi]1, [phi]3). Discrepancies in the measured values of the sides and angles could be an indication of New Physics beyond the Standard Model (SM) due to enhanced branching fractions or modified CP asymmetries. The experimental measurements of branching fractions, CP asymmetries, polarization and phases (both weak and strong) can be compared to theoretical models based on, for example, QCD factorization, SU(3) symmetry and Lattice QCD.