› › Measurement Of The Branching Fractions For Inclusive B And Bar B

MEASUREMENT OF THE BRANCHING FRACTIONS FOR INCLUSIVE B[sup -] AND [bar B][sup 0] DECAYS TO FLAVOR-TAGGED D, D[sub S] AND LAMBDA[sub C].

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File Size : 43,44 MB

Release : 2004

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The authors report on the inclusive branching fractions of B[sup -] and of [bar B][sup 0] mesons decaying to D[sup 0]X, [bar D][sup 0]X, D[sup +]X, D[sup -]X, D[sub s][sup +]X, D[sub s][sup -]X, [Lambda][sub c][sup +]X, [bar [Lambda]][sub c][sup -]X, based on a sample of 88.9 million B[bar B] events recorded with the BABAR detector at the [Upsilon](4S) resonance. Events are selected by completely reconstructing one B and searching for a reconstructed charmed particle in the rest of the event. The authors measure the number of charmed and of anit-charmed particles per B decay and derive the total charm yield per B[sup -] decay, n[sub c][sup -] = 1.313 [+-] 0.037 [+-] 0.037 [+-] 0.062[sub -0.043][sup +0.063], and per [bar B][sup 0] decay, n[sub c][sup 0] = 1.276 [+-] 0.062 [+-] 0.058[sub -0.046][sup +0.066] where the first uncertainty is statistical, the second is systematic, and the third reflects the charm branching-fraction uncertainties.



MEASUREMENT OF THE BRANCHING FRACTIONS FOR INCLUSIVE B− AND {bar B}° DECAYS TO FLAVOR-TAGGED D, D{sub S} AND LAMBDA{sub C}

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Page : 5 pages

File Size : 20,30 MB

Release : 2004

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The authors report on the inclusive branching fractions of B− and of {bar B}° mesons decaying to D°X, {bar D}°X, DX, D−X, D{sub s}+X, D{sub s}−X,?{sub c}+X, {bar {Lambda}}{sub c}−X, based on a sample of 88.9 million B{bar B} events recorded with the BABAR detector at the?(4S) resonance. Events are selected by completely reconstructing one B and searching for a reconstructed charmed particle in the rest of the event. The authors measure the number of charmed and of anit-charmed particles per B decay and derive the total charm yield per B− decay, n{sub c}− = 1.313 ± 0.037 ± 0.037 ± 0.062{sub -0.043}{sup +0.063}, and per {bar B}° decay, n{sub c}° = 1.276 ± 0.062 ± 0.058{sub -0.046}{sup +0.066} where the first uncertainty is statistical, the second is systematic, and the third reflects the charm branching-fraction uncertainties.



Measurement of the Inclusive Branching FractionsB(B- to D+ [pi]- [pi]- ) and B(B- to D*^+ [pi]- [pi]- ).

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Page : 135 pages

File Size : 44,8 MB

Release : 2007

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The D$0\atop{J}$ is a family of four orbitally excited mesons: D$*\atop{2}$(2460)0, D1(2420)0, D1(j = 1/2)-, and D$*\atop{0}$(j = 1/2)0. This dissertation presents the measurements of the inclusive branching fractions, [beta](B- 2!D*+[pi]-[pi]- ) and [beta](B- 2!D+[pi]-[pi]- ). The D$0\atop{J}$ provides an intermediate resonance for those two modes. The data used for this analysis consists of Runs 1-5 with total integrated luminosity of 343.38 fb-1, which is corresponding to 383.92 million B$\bar{B}$ pairs, provided by the BABAR detector at the PEP-II asymmetric B Factory. The values presented are: [beta](B- 2!D+[pi]-[pi]- ) = (1.12 ± 0.02 ± 0.08) x 10-3; [beta](B- 2!D*+[pi]-[pi]- ) = (1.67 ± 0.03 ± 0.13) x 10-3.





Measurement of Inclusive B Semileptonic Branching Fractions at the Z Resonance

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Release : 2000

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This document presents a new measurement of inclusive b semileptonic branching fractions B(b-->l) and B(b-->c-->l). The b-->l and b-->c-->l are separated by a means that uses correlation between the final state lepton charge and that of its parent b quark as a constraint. Monte Carlo counts of electrons and muons are calibrated to the data using a newly developed technique based on pairs of mutually independent tests for each particle hypothesis separately. The data sample consists of about 550,000 hadronic Z decays collected at the SLD between 1993 and 1998. Upon analysis of electron and muon counts in 61602 hadronic event hemispheres tagged as containing either a b or a b-bar, the author reports: B(b-->e) = 0.0949"0.0049"0.0050, B(b-->mu) = 0.1066"0.0038"0.0049, combined B(b-->l) = 0.1015"0.0030"0.0035; and B(b-->c-->e) = 0.0811"0.0053"0.0030, B( -->b-->c-->mu) = 0.0717"0.0045"0.0024, combined B(b-->c-->l) = 0.0756"0.0034"0.0019.



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

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Page : 19 pages

File Size : 12,52 MB

Release : 2005

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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.



Measurement of the Inclusive Semileptonic Branching Fraction of B Mesons Using Fully Reconstructed B-Mesons as Tags in the BABAR Experiment

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File Size : 23,61 MB

Release : 2004

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The BABAR experiment at SLAC provides an opportunity for measurement of the Standard Model parameters describing CP violation. A method of measuring the CKM matrix element V[sub cb] using Inclusive Semileptonic B decays in events tagged by a fully reconstructed decay of one of the B mesons is presented here. This mode is considered to be one of the most powerful approaches due to its large branching fraction, simplicity of the theoretical description and very clean experimental signatures. Using fully reconstructed B mesons to flag B[bar B] event we were able to produce the spectrum and branching fraction for electron momenta P[sub C.M.S.]> 0.5 GeV/c. Extrapolation to the lower momenta has been carried out with Heavy Quark Effective Theory. The branching fractions are measured separately for charged and neutral B mesons. For 82 fb[sup -1] of data collected at BABAR we obtain: BR(B[sup [+-]] [yields] X e[bar [nu]]) = 10.63 [+-] 0.24 [+-] 0.29%, BR(B[sup 0] [yields] X e[bar [nu]]) = 10.68 [+-] 0.34 [+-] 0.31%, averaged BR(B [yields] X e[bar [nu]]) = 10.65 [+-] 0.19 [+-] 0.27%, ratio of Branching fractions BR(B[sup [+-]])/BR(B[sup 0]) = 0.996 [+-] 0.039 [+-] 0.015 (errors are statistical and systematic, respectively). They also obtain V[sub cb] = 0.0409 [+-] 0.00074 [+-] 0.0010 [+-] 0.000858 (errors are: statistical, systematic and theoretical).



Measurement of the Inclusive Charmless Semileptonic Branching Ratio of B Mesons and Determination Of[verticalV[sub Ub][vertical

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File Size : 21,67 MB

Release : 2003

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We report a measurement of the inclusive charmless semileptonic branching fraction of B mesons in a sample 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 B meson. The number of signal events is extracted from the hadronic mass distribution and is used to determine the ratio of branching fractions[Beta]([bar B][yields] X[sub u]l[bar[nu]])/[Beta]([bar B][yields] Xl[bar[nu]])= (2.06[+-] 0.25(stat)[+-] 0.23(syst)[+-] 0.36(theo)) x 10[sup -2]. Using the measured branching fraction for inclusive semileptonic B decays, we find[Beta]([bar B][yields] X[sub u]l[bar[nu]])= (2.24[+-] 0.27(stat)[+-] 0.26(syst)[+-] 0.39(theo)) x 10[sup -3] and derive the CKM matrix elementV[sub ub]= (4.62[+-] 0.28(stat)[+-] 0.27(syst)[+-] 0.48(theo)) x 10[sup -3].



Study of Inclusive $B^-$ and $\bar{B}^0$ Decays ToFlavor-Tagged $D$, $D_s$ and $\Lambda_c$

Author : B. Aubert

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File Size : 35,63 MB

Release : 2006

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We report on a study of inclusive B{sup -} and {bar B}{sup 0} meson decays to D{sup 0}X, {bar D}{sup 0}X, D{sup +}X, D{sup -}X, D{sub s}{sup +}X, D{sub s}{sup -}X, {Lambda}{sub c}{sup +}X, {bar {Lambda}}{sub c}{sup -}X, based on a sample of 231 million B{bar B} events recorded with the BABAR detector at the {Upsilon}(4S) resonance. Events are selected by completely reconstructing one B and searching for a reconstructed charm particle in the rest of the event. From the measured branching fractions of these decays, we infer the number of charm and anti-charm particles per {bar B} decay, separately for charged and neutral parents. We derive the total charm yield per B{sup -} decay, n{sub c}{sup -} = 1.202 {+-} 0.023 {+-} 0.040{sub -0.029}{sup +0.035}, and per {bar B}{sup 0} decay, n = 1.193 {+-} 0.030 {+-} 0.034{sub -0.035}{sup +0.044} where the first uncertainty is statistical, the second is systematic, and the third reflects the charm branching-fraction uncertainties. We also present the charm momentum distributions measured in the {bar B} rest frame.



Measurement of Partial Branching Fractions of Inclusive Charmless B Meson Decays to K, K0, and Pi

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Page : 8 pages

File Size : 19,49 MB

Release : 2011

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The authors present measurements of partial branching fractions of B 2!KX, B 2!K° X, and B 2![pi]+X, where X denotes any accessible final state above the endpoint for B decays to charmed mesons, specifically for momenta of the candidate hadron greater than 2.34 (2.36) GeV for kaons (pions) in the B rest frame. These measurements are sensitive to potential new-phisics particles which could enter the b 2!s(d) loop transitions. The analysis is performed on a data sample consisting of 383 x 106 B{bar B} pairs collected with the BABAR detector at the PEP-II e+e− asymmetric energy collider. The results are in agreement with standard model predictions and exclude large enhancements of the inclusive branching fraction due to sources of new physics.