Leptonic Decays of the Charged B Meson
Leptonic Decays of the Charged B Meson

Author: Luke Andrew Corwin

Publisher:

Published: 2008

Total Pages: 148

ISBN-13:

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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.

Study of B Meson Decays with Excited Eta and Eta-prime Mesons
Study of B Meson Decays with Excited Eta and Eta-prime Mesons

Author:

Publisher:

Published: 2008

Total Pages: 7

ISBN-13:

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Using 383 million B{bar B} pairs from the BABAR data sample, they report results for branching fractions of six charged B-meson decay modes, where a charged kaon recoils against a charmless resonance decaying to K{bar K}* or [eta][pi][pi] final states with mass in the range (1.2-1.8) GeV/c2. They observe a significant enhancement at the low K{bar K}* invariant mass which is interpreted as B 2![eta](1475)K, find evidence for the decay B+ 2![eta](1295)K+, and place upper limits on the decays B+ 2![eta](1405)K+, B+ 2!f1(1285)K+, B+ 2!f1(1420)K+, and B+ 2![phi](1680)K+.

Leptonic Decays of the Charged B Meson
Leptonic Decays of the Charged B Meson

Author:

Publisher:

Published: 2008

Total Pages: 176

ISBN-13:

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We present a search for the decay B+ 2!l+[nu] (= [tau], [mu], or e) in (458.9±5.1)×106 [Upsilon](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- 2!D0l -$\bar{v}$X) is selected, and in the recoil a search for B+ 2! +[nu]l signal is performed. The [tau] is identified in the following channels: [tau]+ 2!e+[nu]e$\bar{v}$[tau], [tau]+ 2![mu]+[nu][mu]$\bar{v}$[tau], [tau]+ 2![pi]+$\bar{v}$[tau], and [tau]+ 2![pi]+[pi]0$\bar{v}$[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(B+ 2![tau]+[nu][tau]) = (1.8 ± 0.8 ± 0.1) × 10-4, which excludes zero at 2.4[sigma], and fB = 255 ± 58 MeV. Combination with the hadronically tagged measurement yields B(B+ 2![tau]+[nu][tau]) = (1.8 ± 0.6) × 10-4. We also set preliminary limits on the branching fractions at B(B+ 2!e+[nu]e)

Leptonic Decays of Charged D and Ds Mesons
Leptonic Decays of Charged D and Ds Mesons

Author: Nabil Menaa

Publisher:

Published: 2007

Total Pages: 146

ISBN-13: 9780549045328

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Using 281 pb--1 of data taken on the psi(3770) resonance and 314 pb--1 of data near or at 4170 MeV collected with the CLEO-c detector, we present two analyses to study the purely leptonic decays of charmed and charmed strange charged mesons.