Download or read book A Search for the Decays B Arrow L nu and B degree arrow L Tau l written by Miika A. Klemetti and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "We present searches for the leptonic decays B + [arrow] l+nu and the lepton flavor violating decays B[degree][arrow] l[symbol][tau][symbol], where l = e, [mu], with data collected by the BABAR experiment at SLAC. These searches utilize a technique in which we fully reconstruct the accompanying B̄ in [Upsilon](4S)[arrow] BB̄ events, and look for a monoenergetic lepton in the signal B frame. The signal yield in the data is extracted from a fit to the signal lepton candidate momentum distribution in the signal B rest frame. Using a data sample of approximately 378 million BB̄ pairs (342 fb-1), we find no evidence of signal in any of the decay modes. Branching fraction upper limits of B (B+[arrow] e +[nu])
Download or read book A Search for the Decays B arrow L nu and B0 arrow L tau l written by Miika A. Klemetti and published by . This book was released on 2007 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Search for B Tau Nu Tau Recoiling Against B D0 L Nu bar L X written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a search for the decay B[sup+][yields][tau][sup+][nu][sub[tau]] in 88.9 x 10[sup 6][Upsilon](4S) decays recorded with the BABAR detector at the SLAC B-Factory. A sample of semi-exclusive, semi-leptonic B decays (B[sup -][yields] D[sup 0][ell][sup -][bar[nu]][sub[ell]]X), where X is either a photon, [pi][sup 0], or nothing, is used to identify the daughter particles that are associated with the other B meson in each event. These particles are searched for evidence of a one-prong leptonic B[sup+][yields][tau][sup+][nu][sub[tau]] decay. For this data sample we set a preliminary upper limit on the branching fraction of[Beta](B[sup+][yields][tau][sup+][nu][sub[tau]])
Download or read book A Search for B Tau Nu Tau Recoiling Against B D0 L Nu bar L X written by Stephen J. Sekula and published by . This book was released on 2003 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a search for the decay B{sup +} {yields} {tau}{sup +}{nu}{sub {tau}} in 88.9 x 10{sup 6} {Upsilon}(4S) decays recorded with the BABAR detector at the SLAC B-Factory. A sample of semi-exclusive, semi-leptonic B decays (B{sup -} {yields} D{sup 0}{ell}{sup -}{bar {nu}}{sub {ell}}X), where X is either a photon, {pi}{sup 0}, or nothing, is used to identify the daughter particles that are associated with the other B meson in each event. These particles are searched for evidence of a one-prong leptonic B{sup +} {yields} {tau}{sup +}{nu}{sub {tau}} decay. For this data sample we set a preliminary upper limit on the branching fraction of {Beta}(B{sup +} {yields} {tau}{sup +}{nu}{sub {tau}})
Download or read book Searches for the Decays B0 to L Tau and B to L Nu L written by and published by . This book was released on 2008 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present searches for the leptonic decays B → l+? and the lepton flavor violating decays B° → l{sup {+-}}?{sup {-+}}, where l = e,?, with data collected by the BABAR experiment at SLAC. This search demonstrates a novel technique in which we fully reconstruct the accompanying {bar B} in?(4S) → B{bar B} events, and look for a monoenergetic lepton from the signal B decay. The signal yield is extracted from a fit to the signal lepton candidate momentum distribution in the signal B rest frame. Using a data sample of approximately 378 million B{bar B} pairs (342 fb−1), we find no evidence of signal in any of the decay modes. Branching fraction upper limits of?(B+ → e+?)
Download or read book Search for the Rare Decay K L right Arrow pi 0 pi 0 gamma written by David Edward Smith and published by . This book was released on 2006 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Search for B sub tau Recoiling Against B D l bar nu sub ell written by and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present a search for the decay B -->?+?{sub?} in 124.1 x 106?(4S) decays recorded with the BABAR detector at the SLAC PEP-II B-Factory. A sample of events with one reconstructed exclusive semi-leptonic B decay (B− --> D*°l−{bar?}{sub {ell}}) is selected, and in the recoil a search for B+ -->?+?{sub?} signal is performed. The? is identified in the following channels:?+ --> e+?{sub e}{bar?}{sub?} -->?+?{sub {mu}}{bar?}{sub?},?+ -->?+{bar {nu}}{sub?}, {tau}+ -->?+?°{bar {nu}}{sub {tau}}, {tau}+ -->?+?−?+{bar {nu}}{sub {tau}}. The authors find no evidence of signal, and they set a preliminary upper limit on the branching fraction of B(B+ --> {tau}+{nu}{sub {tau}}) 4.3 x 10−4 at the 90% confidence level (CL). This result is then combined with a statistically independent BABAR search for B+ -- {tau}+{nu}{sub {tau}} to give a combined preliminary limit of B(B+ --> {tau}+{nu}{sub {tau}})
Download or read book A Search for B Tau Nu Recoiling Against B D0 L Nu X written by and published by . This book was released on 2009 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present a search for the decay B → l+?{sub l} (l =?,?, or e) in (458.9 ± 5.1) x 106 B{bar B} pairs recorded with the BABAR detector at the PEP-II B-Factory. They search for these B decays in a sample of B+B− events where one B-meson is reconstructed as B− → D°{ell}−{bar?}X. Using the method of Feldman and Cousins, they obtain?(B+ →?+?{sub {tau}}) = (1.7 ± 0.8 ± 0.2) x 10−4, which excludes zero at 2.3?. They interpret the central value in the context of the Standard Model and find the B meson decay constant to be f{sub B}2 = (62 ± 31) x 103 MeV2. They find no evidence for B+ → e+?{sub e} and B+ →?+?{sub?} and set upper limits at the 90% C.L.?(B+ → e+?{sub e})
Download or read book Studies of the Decays B 0 right Arrow D D B0 right Arrow D D B 0 right Arrow D D B 0 right Arrow D D B0 right Arrow D D B0 right Arrow D D B 0 right Arrow D D and B0 right Arrow D D written by Edward Michael Potter and published by . This book was released on 2000 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rare Decays in BaBar written by Emmanuele Salvati and published by . This book was released on 2010 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Search for the Decay Modes B to H Tau L written by and published by . This book was released on 2012 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a search for the lepton flavor violating decay modes B{sup ±} → h{sup ±} [tau]l (h = K, [pi]; l = e, [mu]) using the BABAR data sample, which corresponds to 472 million B{bar B} pairs. The search uses events where one B meson is fully reconstructed in one of several hadronic final states. Using the momenta of the reconstructed B, h, and l candidates, we are able to fully determine the [tau] four-momentum. The resulting [tau] candidate mass is our main discriminant against combinatorial background. We see no evidence for B{sup ±} → h{sup ±} [tau]l decays and set a 90% confidence level upper limit on each branching fraction at the level of a few times 10−5.
Download or read book A Study of B right Arrow J psi K 0X Decays written by Stephen John Bailey and published by . This book was released on 2001 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Search for the Rare Decays B to Pi L l and B0 to Eta L l written by and published by . This book was released on 2013 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 A Search for B to ell nu ell Recoiling Against B to D 0 ell bar nu X written by and published by . This book was released on 2009 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a search for the decay B → l+?{sub l} (l =?,?, or e) in (458.9 ± 5.1) x 106?(4S) decays recorded with the BABAR detector at the SLAC PEP-IIB-Factory. A sample of events with one reconstructed exclusive semi-leptonic B decay (B− → D° l−{bar?}X) is selected, and in the recoil a search for B+ → {ell}+?{sub {ell}} signal is performed. The? is identified in the following channels:?+ → e+?{sub e}?{sub?},?+ →?+?{sub?}?{sub?},?+ →?+?{sub?}, and {tau}+ →?+?°?{sub {tau}}. The analysis strategy and the statistical procedure is set up for branching fraction extraction or upper limit determination. We determine from the dataset a preliminary measurement of?(B+ → {tau}+?{sub {tau}}) = (1.8 ± 0.8 ± 0.1) x 10−4, which excludes zero at 2.4?, and f{sub B} = 230 ± 57 MeV. Combination with the hadronically tagged measurement yields?(B+ → e+?{sub e}) = (1.8 ± 0.6) x 10−4. We also set preliminary limits on the branching fractions at?(B+ → e+?{sub e})
Download or read book Evidence for an Excess of B D Tau Nu Decays written by Manuel Franco Sevilla and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on the full BaBar data sample, we report improved measurements of the ratios R(D(*)) = B(B -> D(*) Tau Nu)/B(B -> D(*) l Nu), where l is either an electron or a muon. These ratios are sensitive to new physics contributions in the form of a charged Higgs boson. We measure R(D) = 0.440 +- 0.058 +- 0.042 and R(D*) = 0.332 +- 0.024 +- 0.018, which exceed the Standard Model expectations by 2.0 sigma and 2.7 sigma, respectively. Taken together, our results disagree with these expectations at the 3.4 sigma level, which could be an indication of beyond-the-Standard- Model processes affecting these decays. We examine whether the excess in R(D) and R(D*) could be explained by a charged Higgs boson in the type II two-Higgs-doublet model, which describes the Higgs sector of the Minimal Supersymmetric model at tree level. We exclude this possibility in the full parameter space with a probability of at least 99.8%, or 3.1sigma significance. We also report the observation of the decay B -> D Tau Nu, with a significance of 6.8 sigma.
Download or read book Bbar right Arrow pi l nu Bar at Three Lattice Spacings written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The increasing accuracy of experimental results for the exclusive, semileptonic decay [anti B][yields][pi]l[anti [nu]] requires a similarly acucrate calculation of the hadronic matrix elements, to determine [vert-bar]V[sub ub][vert-bar]. We present preliminary results for the form factors of the B to light meson decay mode. Using results from three lattices in the range 5.7[
