3 research outputs found
Evidence for an excess of B -> D(*) Tau Nu decays
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 e or
mu. 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. This excess cannot be explained by a
charged Higgs boson in the type II two-Higgs-doublet model. We also report the
observation of the decay B -> D Tau Nu, with a significance of 6.8 sigma.Comment: Expanded section on systematics, text corrections, improved the
format of Figure 2 and included the effect of the change of the Tau
polarization due to the charged Higg
Evidence for an Excess of (B)over-bar -> D-(*()) tau(-)(nu)over-bar(tau) Decays
Based on the full BABAR data sample, we report improved measurements of the ratios R(D-(*())) = B((B) over bar -> D-(*()) tau(-)(nu) over bar (tau))/B((B) over bar -> D-(*()) l(l)(-)(nu) over bar (l), where l is either e or mu. 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. This excess cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model. RI Monge, Maria Roberta/G-9127-201
Observation of the Decay B^{-}→D_{s}^{(*)+}K^{-}ℓ^{-}ν[over ¯]_{ℓ}
We report the observation of the decay B(-) -> D(s)(()*()+)K(-)l(-)(nu) over bar (l) based on 342 fb(-1) of data collected at the Y(4S) resonance with the BABAR detector at the PEP-II e(+)e(-) storage rings at SLAC. A simultaneous fit to three D(s)(+) decay chains is performed to extract the signal yield from measurements of the squared missing mass in the B meson decay. We observe the decay B(-) -> D(s)(()*()+)K(-)l(-)(nu) over bar (l) with a significance greater than 5 standard deviations (including systematic uncertainties) and measure its branching fraction to be B(B(-) -> D(s)(()*())K(-)l(-)(nu) over bar (l) = [6.13(-1.03)(+1.04)(stat) +/- 0.43(syst) +/- 0.51 (B(D(s)))] X 10(-4), where the last error reflects the limited knowledge of the D(s) branching fractions