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 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 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 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 Decays at BaBar written by and published by . This book was released on 2007 with total page 5 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-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+ = 0.103+/-0.006+/-0.005, neutral B mesons b0 = 0.104+/-0.008+/-0.005, their average b = 0.104+/-0.005+/-0.004, and their ratio b+/b0 = 0.99+/-0.10+/-0.03.

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 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 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 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 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 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 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 Measurement of the Branching Fraction of the Semileptonic Decay Anti B0 D Mu Anti Muon Neutrino in the BaBar Experiments written by Douglas Michael Thiessen and published by . This book was released on 2005 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a measurement of the branching fraction for the exclusive semileptonic decay {bar B}{sup 0} {yields} D*{sup +}{mu}{sup -}{nu}{sub {mu}}. This decay is essentially the decay of a b quark to a c quark inside the meson with the release of a muon and neutrino, and it provides a very clean signal for measuring various B meson decay properties. the data for this measurement consist of 22.3 million B{bar B} pairs collected by the BABAR detector at the Stanford Linear Accelerator Center in 1999-2000. The branching fraction is measured to be {Beta}({bar B}{sup 0} {yields} D*{sup +}{mu}{sup -}{bar {nu}}{sub {mu}}) = [4.72 {+-} 0.10 (data stat.) {+-} 0.06 (MC stat.) {+-} 0.20 (syst.) {+-} 0.17 (other {Beta})]%.

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 Leptonic Decays of the Charged B Meson written by Luke Andrew Corwin and published by . This book was released on 2008 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: We present a search for the decay of the charged B meson into a charged lepton and a neutrino 458.9 million Upsilon(4S) decays recorded with the Babar detector at the SLAC PEP-II B-Factory. A sample of events with one reconstructed exclusive semileptonic B decay is selected, and in the recoil a search for the signal decay is performed. The tau lepton is identified in decays to an electron and two neutrinos; a muon and two neutrinos; a charged pion and a neutrino; or a charged pion, a neutral pion, and a neutrino. The analysis strategy and the statistical procedure is set up for branching fraction extraction or upper limit determination. We determine from the data set a preliminary measurement of the branching fraction a charged B decaying to a tau lepton and a neutrino = (1.8 " 0.8 " 0.1)E-4, which excludes zero at 2.4 standard deviations. We extract the B meson decay constant = 255 " 58 MeV. Combination with the hadronically tagged measurement yields (1.8 " 0.6)E-4. We also set preliminary limits on the branching fraction of charged B decaying to an electron and a neutrino at 7.7E-6 and the charged B decaying to a muon and a neutrino at 11E-6. The limits are at the 90% confidence level.

Download or read book Determination of verticalV sub Ub vertical in Inclusive Semileptonic B Meson Decays written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.