Download or read book Measurement of the Decay B Omega L Nu with the Babar Detector and Determination of V ub written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We measure the branching fraction of the exclusive charmless semileptonic decay B 2![omega]l[nu]{sub l}, where l is either an electron or a muon, with the charged B meson recoiling against a tag B meson decaying in the charmed semileptonic modes B 2!Dl[nu]{sub {ell}} or B 2!D*{ell}[nu]{sub {nu}}. The measurement is based on a dataset of 426.1 fb−1 of ee− collisions at a CM energy of 10.58 GeV recorded with the BABAR detector at the PEP-II asymmetric B Factory located at the SLAC National Accelerator Laboratory. We also calculate the relevant B 2![omega] hadronic form factors to determine the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element.
Download or read book Measurement of the Decay B u2192 l with the BaBar Detector and Determination of written by and published by . This book was released on 2010 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: We measure the branching fraction of the exclusive charmless semileptonic decay B→ ?l?l, where l is either an electron or a muon, with the charged B meson recoiling against a tag B meson decaying in the charmed semileptonic modes B → Dl?l or B → D*l?l. The measurement is based on a dataset of 426.1 fb-1 of e+e- collisions at a CM energy of 10.58 GeV recorded with the BABAR detector at the PEP-II asymmetric B Factory located at the SLAC National Accelerator Laboratory. We also calculate the relevant B → ? hadronic form factors to determine the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element.
Download or read book Analysis of B 2 omega l nu Decays With BaBar written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Study of the Decay B0bar D Omega Pi written by B. Aubert and published by . This book was released on 2006 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on a study of the decay {bar B}{sup 0} {yields} D*{sup +}{omega}{pi}{sup -} with the BABAR detector at the PEP-II B-factory at the Stanford Linear Accelerator Center. Based on a sample of 232 million B{bar B} decays, we measure the branching fraction {Beta}({bar B}{sup 0} {yields} D*{sup +}{omega}{pi}{sup -}) = (2.88 {+-} 0.21(stat.) {+-} 0.31(syst.)) x 10{sup -3}. We study the invariant mass spectrum of the {omega}{pi}{sup -} system in this decay. This spectrum is in good agreement with expectations based on factorization and the measured spectrum in {tau}{sup -} {yields} {omega}{pi}{sup -} {nu}{sub {tau}}. We also measure the polarization of the D*{sup +} as a function of the {omega}{pi}{sup -} mass. In the mass region 1.1 to 1.9 GeV we measure the fraction of longitudinal polarization of the D*{sup +} to be {Lambda}{sub L}/{Lambda} = 0.654 {+-} 0.042(stat.) {+-} 0.016(syst.). This is in agreement with the expectations from heavy-quark effective theory and factorization assuming that the decay proceeds as {bar B}{sup 0} {yields} D*{sup +}{rho}(1450), {rho}(1450) {yields} {omega}{pi}{sup -}.
Download or read book Bd Mixing Measurements 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: The B[sup 0][bar B][sup 0] oscillation frequency[Delta] m[sub d] has been measured with the BABAR detector at the PEP-II asymmetric B factory with different experimental techniques. The discussion here is focused on the recent simultaneous measurement of[Delta] m[sub d] and[tau][sub B[sup 0]] with exclusively reconstructed B[sup 0][yields] D*[sup -][ell][sup+][nu][sub l] decays, based on 23 million B[bar B] pairs collected by BABAR. The measurements of[Delta] m[sub d] with fully reconstructed hadronic decays and with dilepton events are also reviewed. The average BABAR result is[Delta] m[sub d]= 0.500[+-] 0.008[+-] 0.006 ps[sup -1].
Download or read book ODRZYWOL PRZYTYK written by and published by . This book was released on 1990 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Determination of the CKM matrix Element Vub from the Electron Energy Spectrum Measured in Inclusive B X U E Ypsilon Decay with the BABAR Detector written by and published by . This book was released on 2012 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of the B phi K Decay Amplitudes written by and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: With a sample of about 227 million B{bar B} pairs recorded with the BABAR detector at the PEP-II storage ring the authors perform a full angular analysis of the decay B° --> [phi]K*°(892). They measure the branching fraction to be (9.2 ± 0.9 ± 0.5) x 10°6 and determine the fractions of longitudinal and parity-odd transverse contributions as f{sub L} = 0.52 ± 0.05 ± 0.02 and F{sub {perpendicular}} = 0.22 ± 0.05 ± 0.02, respectively. The phases of the parity-even and parity-odd transverse amplitudes relative to the longitudinal amplitude are found to be [phi]{sub {parallel}} = 2.34{sub -0.20}{sup +0.23} ± 0.05 rad and [phi]{sub {perpendicular}} = 2.47 ± 0.25 ± 0.05 rad, respectively. The authors measure five CP asymmetries which provide important limits on CP violation originating from new physics. They also observe the decay B° --> [phi]K*°(1430).
Download or read book A Search for the Rare Decay B tau tau at the BaBar Experiment written by Christopher Thomas Potter and published by . This book was released on 2006 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Standard Model of particle physics predicts that the branching ratio for the rare decay B{sup 0} {yields} {tau}{sup +}{tau}{sup -} is 3.1 x 10{sup -8}, though untested models which could supersede it predict large enhancements. This dissertation describes the search for this rare decay in 210.4 fb{sup -1} of B{sup 0}{bar B}{sup 0} data collected at the {Upsilon}(4S) resonance in the Babar detector at the Stanford Linear Accelerator Center. In the analysis, one neutral B meson is fully reconstructed in a hadronic mode and recoil events which are consistent with each tau decaying in a mode {tau} {yields} {pi}{nu}, {rho}{nu}, or l{nu}{bar {nu}} are selected. There is no evidence for signal. The result is consistent with a downward fluctuation by 1.1 statistical standard deviations of the expected Standard Model background. Taking the expected background, the number of observed events and the expected statistical and systematic errors into account yields 2.7 x 10{sup -3} as the upper limit for B{sup 0} {yields} {tau}{sup +}{tau}{sup -} at the 90% confidence level.
Download or read book Measurement of the B sup 0 phi K sup 0 Decay Amplitudes written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: With a sample of about 227 million B[bar B] pairs recorded with the BABAR detector at the PEP-II storage ring the authors perform a full angular analysis of the decay B[sup 0] --> [phi]K*[sup 0](892). They measure the branching fraction to be (9.2 [+-] 0.9 [+-] 0.5) x 10[sup 06] and determine the fractions of longitudinal and parity-odd transverse contributions as f[sub L] = 0.52 [+-] 0.05 [+-] 0.02 and F[sub [perpendicular]] = 0.22 [+-] 0.05 [+-] 0.02, respectively. The phases of the parity-even and parity-odd transverse amplitudes relative to the longitudinal amplitude are found to be [phi][sub [parallel]] = 2.34[sub -0.20][sup +0.23] [+-] 0.05 rad and [phi][sub [perpendicular]] = 2.47 [+-] 0.25 [+-] 0.05 rad, respectively. The authors measure five CP asymmetries which provide important limits on CP violation originating from new physics. They also observe the decay B[sup 0] --> [phi]K*[sup 0](1430).
Download or read book Measurements of the Rare Decays B Kl l and B K l l written by J. C. Chen and published by . This book was released on 2005 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present measurements of the flavor-changing neutral current decays B {yields} K{ell}{sup +}{ell}{sup -} and B {yields} K*{ell}{sup +}{ell}{sup -}, where {ell}{sup +}{ell}{sup -} is either an e{sup +}e{sup -} or {mu}{sup +}{mu}{sup -} pair. The data sample comprises 229 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II e{sup +}e{sup -} storage ring.
Download or read book Reconstruction of B D E Nu Decays and Determination of Vcb written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Analysis of B Omega Lv Decays with BaBar SULI written by Yi-Wen Chu and published by . This book was released on 2005 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 {yields} wlv, which can be used to determine the Cabbibo-Kobayashi-Maskawa matrix element V{sub ub}. Using simulated event samples, this study focuses on determining criteria on variables for selection of B {yields} wlv signal and suppression of background from other types of B{bar B} 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 B{bar B} events recorded by BaBar in e{sup +}e{sup -} collisions at the {Upsilon}(4S) resonance, we obtain a yield of 115 {+-} 19 B {yields} wlv decays.
Download or read book Measurement Of verticalV sub Cb vertical Using bar B sup 0 yields D sup ell sup bar nu sub ell 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 preliminary measurement ofV[sub cb] and the branching fraction[Beta]([bar B][sup 0][yields] D*[sup+][ell][sup -][bar[nu]][sub[ell]]) has been performed based on a sample of about 55,700[bar B][sup 0][yields] D*[sup+][ell][sup -][bar[nu]][sub[ell]] decays recorded with the BABAR detector. The decays are identified in the D*[sup+][yields] D[sup 0][pi][sup+] final state, with the D[sup 0] reconstructed in three different decay modes. The differential decay rate is measured as a function of the relativistic boost of the D*[sup+] in the[bar B][sup 0] rest frame. The value of the differential decay rate at ''zero recoil'', namely the point at which the D*[sup+] is at rest in the[bar B][sup 0] frame, is predicted in Heavy Quark Effective Theory as a kinematic factor times F(1)V[sub cb], where F is the unique form factor governing the decay. We extrapolate the measured differential decay rate to the zero recoil point and obtain F(1)V[sub cb]= (34.03[+-] 0.24[+-] 1.31) x 10[sup -3]. Using a theoretical calculation for F(1) we extractV[sub cb]= (37.27[+-] 0.26(stat.)[+-] 1.43(syst.)[sub -1.2][sup+1.5](theo.)) x 10[sup -3]. From the integrated decay rate we obtain[Beta]([bar B][sup 0][yields] D*[sup+][ell][sup -][bar[nu]][sub[ell]])= (4.68[+-] 0.03[+-] 0.29)%.
Download or read book Measurement of D0 Lifetime with the BaBar Detector written by and published by . This book was released on 2009 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work is the result of the researchers carried out during a three years Ph. D. period in the BABAR experiment. The first chapter consists in an introduction to the theoretical aspects of the D° meson lifetime determination and CP violation parameters, as well as an overview of the CP violation in the B sector, which is the main topic of the experiment. The description of the experimental apparatus follows with particular attention to the Silicon Vertex Tracker detector, the most critical detector for the determination of decay vertices and thus of lifetimes and time dependent CP violation asymmetries. In the fourth chapter the operation and running of the vertex detector is described, as a result from the experience as Operation Manager of the SVT, with particular attention to the safety of the device and the data quality assurance. The last chapter is dedicated to the determination of the D° meson lifetime with the BABAR detector, which is the main data analysis carried out by the candidate. The analysis is characterized by the selection of an extremely pure sample of D° mesons for which the decay flight length and proper time is reconstructed. The description of the unbinned maximum likelihood fit follows, as well as the discussion of the possible sources of systematic uncertainties. In the appendix is also presented a preliminary study of a possible development regarding the determination of mixing and CP violation parameters for the D° meson.
Download or read book Time Dependent Dalitz Analysis of B0 D K0 Pi Decays for the Measurement of 2beta gamma with the BaBar Detector written by Francesco Polci and published by . This book was released on 2007 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: The CP violation is explained in the Standard Model with three quark generations with an irreducible phase in the Cabibbo-Kobayashi-Maskawa quark mixing matrix. The unitarity of this matrix can be represented in a complex plane as a triangle (called Unitarity Triangle). The measurement of the parameters of the triangle is a powerful test of the Standard Model description of the CP violation. This thesis tries to measure the weak phase 2beta+ gamma through the B0 -> D+ K0 Pi- decays. Respect to the two body decays B0 -> D(*)+ Pi- and B0 -> D+ Rho- presently used for the measurement of the same weak phase, the B0 -> D+ K0 Pi- decays should show up a larger CP asymmetry and does not rely on any theoretical assumption. After a review of all the methods for the measurement of 2beta+gamma, the thesis presents the results of a feasibility study of the measurement with the B0 -> D+ K0 Pi- decays . In a second part, the analysis performed on 316 fb-1 of data collected by the BaBar detector at the B-factory PEP2 is presented, from the selection of the events to the time-dependent Dalitz fit technique used in order to extract the weak phase 2beta+gamma as well as the amplitudes and phases of the intermediate resonances contributing to the decay. The result of the analysis gives the following estimation: 2beta+gamma = 89 +/- 53(stat) +23-14(syst) degrees with an irreducible ambiguity of 180 degrees.
Download or read book Measurement of Branching Fraction and Polarization in the Decay Beta 0 right Arrow rho rho written by Yuriy V. Groysman and published by . This book was released on 2008 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:
