We present a search for the decay B+ l(+)nu(l) (l = tau, mu, or e) in (458.9 5.1) x 10(6) B (B) over bar pairs recorded with the BABAR detector at the PEP-II B-factory. We search for these B decays in a sample of B+B- events where one B- meson is reconstructed as B- D(0)l(-)(nu) over barX. Using the method of Feldman and Cousins, we obtain B(B+ tau(+)nu(tau)) = (1.7 0.8 0.2) x 10(-4), which excludes zero at 2.3 sigma. We interpret the central value in the context of the standard model and find the B meson decay constant to be f(B)(2) = (62 31) x 10(3) MeV2. We find no evidence for B+ e(+)nu(e) and B+ mu(+)nu(mu) and set upper limits at the 90% C. L. B(B+ e(+)nu(e)) < 0.8 x 10(-5) and B(B+ mu(+)nu(mu)) < 1.1 x 10(-5).
Search for B+ -> l(+)nu(l) recoiling against B- -> D(0)l(-)(nu)over-barX
GAZ A;SIMI, GABRIELE;MARGONI, MARTINO;SIMONETTO, FRANCO;STROILI, ROBERTO;VOCI, CESARE;
2010
Abstract
We present a search for the decay B+ l(+)nu(l) (l = tau, mu, or e) in (458.9 5.1) x 10(6) B (B) over bar pairs recorded with the BABAR detector at the PEP-II B-factory. We search for these B decays in a sample of B+B- events where one B- meson is reconstructed as B- D(0)l(-)(nu) over barX. Using the method of Feldman and Cousins, we obtain B(B+ tau(+)nu(tau)) = (1.7 0.8 0.2) x 10(-4), which excludes zero at 2.3 sigma. We interpret the central value in the context of the standard model and find the B meson decay constant to be f(B)(2) = (62 31) x 10(3) MeV2. We find no evidence for B+ e(+)nu(e) and B+ mu(+)nu(mu) and set upper limits at the 90% C. L. B(B+ e(+)nu(e)) < 0.8 x 10(-5) and B(B+ mu(+)nu(mu)) < 1.1 x 10(-5).Pubblicazioni consigliate
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