Article

# First Measurement of the Form Factors in the Decays D0 to rho- e+ nu_e and D+ to rho0 e+ nu_e

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(Impact Factor: 7.51). 12/2011; 110(13). DOI: 10.1103/PhysRevLett.110.131802
Source: arXiv

ABSTRACT

Using the entire CLEO-c psi(3770) to DDbar event sample, corresponding to an
integrated luminosity of 818 pb^-1 and approximately 5.4 x 10^6 DDbar events,
we measure the form factors for the decays D0 to rho- e+ nu_e and D+ to rho0 e+
nu_e for the first time and the branching fractions with improved precision. A
four-dimensional unbinned maximum likelihood fit determines the form factor
ratios to be: V(0)/A_1(0) = 1.48 +- 0.15 +- 0.05 and A_2(0)/A_1(0)= 0.83 +-
0.11 +- 0.04. Assuming CKM unitarity, the known D meson lifetimes and our
measured branching fractions we obtain the form factor normalizations A_1(0),
A_2(0), and V(0). We also present a measurement of the branching fraction for
D^+ to omega e^+ nu_e with improved precision.

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##### Article: New ways to search for right-handed current in B → ρ ℓ ν ¯ decay
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ABSTRACT: An interesting possibility to ease the tension between various determinations of |V_{ub}| is to allow a small right-handed contribution to the standard model weak current. The present bounds on such a contribution are fairly weak. We propose new ways to search for such a beyond standard model contribution in semileptonic B -> rho ell nu decay. Generalized asymmetries in one, two, or three angular variables are introduced as discriminators, which do not require an unbinned analysis of the fully differential distribution, and a detailed study of the corresponding theoretical uncertainties is performed. A discussion on how binned measurements can access all the angular information follows, which may be useful in both B -> rho ell nu and B -> K^* ell^+ ell^-, and possibly essential in the former decay due to backgrounds. The achievable sensitivity from the available BaBar and Belle data sets is explored, as well as from the anticipated 50 ab^{-1} Belle II data.
Physical Review D 08/2014; 90(9). DOI:10.1103/PhysRevD.90.094003 · 4.64 Impact Factor