Download or read book B Meson Semileptonic Decays at BaBar written by and published by . This book was released on 2006 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on the measurements of B-meson semileptonic decays at BABAR. The studies include precision measurement of.

Download or read book Inclusive Semileptonic B Decays at BABAR written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present measurements of the inclusive semileptonic branching fractions of charged and neutral B mesons using 20.6 fb[sup -1] of data measured at the[Upsilon](4S) with the BABAR detector. Events are tagged with a fully reconstructed hadronic decay of a B meson. The correlation between the flavor of the tag B meson and the electron charge allows the separation of prompt semileptonic B decays and cascade semileptonic charm decays. We obtain the preliminary inclusive semileptonic branching fraction of charged B mesons b[sub+]= 0.103[+-] 0.006[+-] 0.005, neutral B mesons b[sub 0]= 0.104[+-] 0.008[+-] 0.005, their average b= 0.104[+-] 0.005[+-] 0.004, and their ratio b[sub+]/b[sub 0]= 0.99[+-] 0.10[+-] 0.03.

Download or read book Semileptonic B Meson Decays at BaBar written by and published by . This book was released on 2013 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Semileptonic B Decays at BABAR written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Recent Results in Semileptonic B Decays with BaBar written by and published by . This book was released on 2012 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this note, recent results of studies of semileptonic B meson decays from BABAR are discussed and preliminary results given. In particular, a recent measurement of?(B → D{sup (*)}??) and the ratio?(B → D{sup (*)}??)/?(B → D{sup (*)}l?) is presented. For the D* mode, a branching fraction of 1.79 ± 0.13(stat) ± 0.17(syst) is found, with a ratio of 0.325 ± 0.023(stat) ± 0.027(syst). For the D mode, the results are 1.04 ± 0.12(stat) ± 0.14(syst) and 0.456 ± 0.053(stat) ± 0.056(syst), respectively. In addition, a study of B{sub s} production and semileptonic decays using data collected in a center-of-mass energy region above the?(4S) resonance is discussed. The semileptonic branching fraction?(B{sub s} → l?X) is measured to be 9.9{sub -2.1}{sup +2.6}(stat){sub -2.0}{sup +1.3}(syst).

Download or read book Studies of Inclusive Semileptonic B Meson Decays with the BABAR Detector written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a brief report on the measurement of the inclusive branching fraction[Beta]([bar B][yields] X[sub c][ell][sup -][bar[nu]]) and the preliminary measurement of the first moment of the hadron mass M[sub X] in such decays. The implications of these results onV[sub cb] are discussed.

Download or read book A MEASUREMENT OF THE LIFETIME AND MIXING FREQUENCY OF NEUTRAL B MESONS WITH SEMILEPTONIC DECAYS IN THE BABAR DETECTOR written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The neutral B meson, consisting of a b quark and an anti-d quark, can mix (oscillate) to its own anti-particle through second-order weak interactions. The measurement of the mixing frequency can constrain the quark mixing matrix in the Standard Model of particle physics. The PEP-II B-factory at the Stanford Linear Accelerator Center provides a very large data sample that enables us to make measurements with much higher precisions than previous measurements, and to probe physics beyond the Standard Model. The lifetime of the neutral B meson[tau][sub B0] and the B[sup 0]-[bar B][sup 0] mixing frequency[Delta]m[sub d] are measured with a sample of approximately 14,000 exclusively reconstructed B[sup 0][yields] D*[sup -][ell][sup+][nu][sub[ell]] signal events, selected from 23 million B[bar B] pairs recorded at the[Upsilon](4S)resonance with the BABAR detector at the asymmetric-energy e[sup+]e[sup -] collider, PEP-II. The decay position of the exclusively reconstructed B is determined by the charged tracks in the final state, and its b-quark flavor at the time of decay is known unambiguously from the charge of the lepton. The decay position of the other B is determined inclusively, and its b-quark flavor at the time of decay is determined (tagged) with the charge of tracks in the final state, where identified leptons or kaons give the most information. The decay time difference of two B mesons in the event is calculated from the distance between their decay vertices and the Lorentz boost of the center of mass. Additional samples of approximately 50,000 events are selected for studies of background events. The lifetime and mixing frequency, along with wrong-tag probabilities and the time-difference resolution function, are measured simultaneously with an unbinned maximum-likelihood fit that uses, for each event, the measured difference in B decay times ([Delta]t), the calculated uncertainty on[Delta]t, the signal and background probabilities, and b-quark tagging for the other B meson. The results are[tau][sub B[sup 0]]= (1.523[sub -0.023][sup+0.024][+-] 0.022) ps and[Delta]m[sub d]= (0.492[+-] 0.018[+-] 0.013) ps[sup -1], where the first error is statistical and the second is systematic. The statistical correlation coefficient between[tau][sub B[sup 0]] and[Delta]m[sub d] is -0.22. This result is consistent with the current world average values, the total errors are comparable with other most-precise measurements.

Download or read book Search for Semileptonic Decays in the B Meson Into the Lambda subscript C Baryon written by Tomohiko Tanabe and published by . This book was released on 2009 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Study of Exclusive Semileptonic B Meson Decays ToTau Leptons written by and published by . This book was released on 2007 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the results of a search for four exclusive semileptonic decays B → D{sup (*)}[tau]−{bar [nu]}{sub [tau]} in 209 fb−1 of data collected with the BABAR detector, corresponding to 232 million e+e- → [Upsilon](4S) → B{bar B} events. We select events with a D{sup (*)} meson and a light lepton (e or [mu]) recoiling against a fully-reconstructed B meson. We perform a fit to the lepton spectrum and missing mass squared to discriminate signal events from backgrounds, predominantly B → D{sup (*)}{tau}−{bar [nu]}{sub {tau}}. A control sample of identified D**l−{bar {nu}}{sub {ell}} events is included in the fit to estimate the background contribution from these decays. We measure [beta](B → D{sub {tau}{nu}}) = (0.86±0.24±0.11±0.06)% and [beta](B → D*{sub {tau}{nu}}) = (1.62±0.31±0.10±0.05)%, where the errors are statistical, systematic, and normalization-mode related, respectively, and where the results are expressed for the {bar B}° lifetime.

Download or read book Measurement of the Branching Fraction for Inclusive Semileptonic B Meson Decays written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A largely model-independent measurement of the inclusive electron momentum spectrum and branching fraction for semileptonic decays of B mesons is presented based on data recorded at the[Upsilon](4S) resonance with the BABAR detector. Backgrounds from secondary charm decays are separated from prompt B decays using charge and angular correlations between the electron from one B meson and a high momentum electron tag from the second B meson. The resulting branching fraction is[Beta](B[yields] Xe[nu])= (10.87[+-] 0.18(stat)[+-] 0.30(syst))%. Based on this measurement we determine the CKM matrix elementV[sub cb].

Download or read book Measurement of the Inclusive Semileptonic Branching Fraction of B Mesons Using Fully Reconstructed B Mesons as Tags in the BABAR Experiment written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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).

Download or read book Study of Exclusive Semileptonic B Meson Decays to Tau Leptons written by Michael A. Mazur and published by ProQuest. This book was released on 2007 with total page 674 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the results of a search for four exclusive semileptonic decays B & rarr; D(*)tau -nutau in 209 fb -1 of data collected with the BABAR detector, corresponding to 232 million e+e - & rarr; Upsilon(4S) & rarr; B B events. We select events with a D (*) meson and a light lepton (e or mu) recoiling against a fully-reconstructed B meson. We perform a fit to the lepton spectrum and missing mass squared to discriminate signal events from backgrounds, predominantly B & rarr; D (*) & ell;-nu & ell; . A control sample of identified D** & ell;- nu & ell; events is included in the fit to estimate the background contribution from these decays. We measure B (B & rarr; Dtaunu) = (0.86+/-0.24+/-0.11+/-0.06)% and B (B & rarr; D*taunu) = (1.62+/-0.31+/-0.10+/-0.05)%, where the errors are statistical, systematic, and normalization-mode related, respectively, and where the results are expressed for the B0 lifetime.

Download or read book B Decays written by Sheldon Stone and published by World Scientific. This book was released on 1994 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book B Meson Semileptonic Form Factors Using Unquenched Lattice QCD written by Emel Gulez and published by . This book was released on 2006 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: We present state-of-the-art unquenched lattice QCD results for B meson semileptonic decay, B [rightarrow] [pi]lv, form factors. We use gauge configurations prepared by the MILC collaboration, which include the effects of the sea quarks, the s quark and two very light quarks (u and d). We employ the nonrelativistic NRQCD action to simulate the heavy b quark and a highly improved staggered quark action (AsqTad) to simulate the sea and valence light quarks. To reduce the uncertainties, we perform matching of the heavy-light current with these highly improved actions through one loop. The perturbative matching accounts for the effects of mixing with dimension 4 operators that are O(1/M) and O(a). We extrapolate the form factors f+(q2) and f0(q2) to their values at the physical pion mass using chiral perturbation theory formulas. Integrating this result, we obtain [integral] [from] 16 GeV2 [to] q2_max [d[gamma]/dq2]d2 (V_ub)2 = 1.46(35) ps−1. Combining this with a preliminary average by the Heavy Flavor Averaging Group (HFAG'05) of recent branching fraction data for exclusive B semileptonic decays from the BaBar, Belle and CLEO collaborations, leads to V_ub = 4.22(30)(51) x 10−3.

Download or read book Measurement of the Semileptonic Anti B to D Tau Anti Nu Tau Decays at BaBar written by and published by . This book was released on 2011 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semileptonic B meson decays into final states containing the [tau] lepton are of interesting as they provide information on the Standard Model as well as a window on new physics effects. We present results on {bar B} → D{sup (*)} [tau]{bar {nu}}{sub {tau}} decays where the second B in the event is fully reconstructed.

Download or read book Semileptonic Decay of B Meson to Vector D Meson written by Xu Fu and published by . This book was released on 1995 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book New Results on Leptonic B Meson Decays at BaBar written by and published by . This book was released on 2008 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.