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) MeV(2). 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 RID C-5223-2009
LUSIANI, Alberto;
2010-01-01
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) MeV(2). 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).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
