Search results for "SEMILEPTONIC DECAY"

Extraction of form Factors from a Four-Dimensional Angular Analysis of B¯→D*ℓ−ν¯ℓ

2019

An angular analysis of the decay B[over ¯]→D^{*}l^{-}ν[over ¯]_{l}, l∈{e,μ}, is reported using the full e^{+}e^{-} collision data set collected by the BABAR experiment at the ϒ(4S) resonance. One B meson from the ϒ(4S)→BB[over ¯] decay is fully reconstructed in a hadronic decay mode, which constrains the kinematics and provides a determination of the neutrino momentum vector. The kinematics of the semileptonic decay is described by the dilepton mass squared, q^{2}, and three angles. The first unbinned fit to the full four-dimensional decay rate in the standard model is performed in the so-called Boyd-Grinstein-Lebed approach, which employs a generic q^{2} parametrization of the underlying f…

Taming the higher power corrections in semileptonic B decays

2016

We study the effect of dimension 7 and 8 operators on inclusive semileptonic B decays and the extraction of |Vcb|. Using moments of semileptonic B decay spectra and information based on the Lowest-Lying State saturation Approximation (LLSA) we perform a global fit of the nonperturbative parameters of the heavy quark expansion including for the first time the O(1/mb^{4,5}) contributions. Higher power corrections appear to have a very small effect on the extraction of |Vcb|, independently of the weight we attribute to the LLSA.

Semileptonic decays of the lightJP=1/2+ground state baryon octet

2008

We calculate the semileptonic baryon octet-octet transition form factors using a manifestly Lorentz covariant quark model approach based on the factorization of the contribution of valence quarks and chiral effects. We perform a detailed analysis of SU(3)-breaking corrections to the hyperon semileptonic decay form factors. We present complete results on decay rates and asymmetry parameters including lepton mass effects for the rates.

Doubly heavy quark baryon spectroscopy and semileptonic decay

2006

Working in the framework of a nonrelativistic quark model we evaluate the spectra and semileptonic decay widths for the ground state of doubly heavy $\Xi$ and $\Omega$ baryons. We solve the three-body problem using a variational ansatz made possible by the constraints imposed by heavy quark spin symmetry. In order to check the dependence of our resultson the inter-quark interaction we have used five different quarkquark potentials which include Coulomb and hyperfine terms coming fromone-gluon exchange, plus a confining term. Our results for the spectra are in good agreement with a previous calculation done using a Faddeev approach. For the semileptonic decay our results for the total decay …

A Measurement of the Bbbar Forward-backward Asymmetry Using the Semileptonic Decay Into Muons

1992

Static properties and semileptonic decays of doubly heavy baryons in a nonrelativistic quark model

2006

We evaluate static properties and semileptonic decays for the ground state of doubly heavy $\Xi, \Xi', \Xi^*$ and $\Omega, \Omega', \Omega^*$ baryons. Working in the framework of a nonrelativistic quark model, we solve the three--body problem by means of a variational ansazt made possible by heavy quark spin symmetry constraints. To check the dependence of our results on the inter-quark interaction we use five different quark-quark potentials that include a confining term plus Coulomb and hyperfine terms coming from one--gluon exchange. Our results for static properties (masses, charge and mass radii, magnetic moments...) are, with a few exceptions for the magnetic moments, in good agreemen…

Lepton-number violation with quasi-Dirac neutrinos

1983

We investigate lepton-number violation in weak interactions with massive Dirac neutrinos. In the framework of a simple $\mathrm{SU}{(3)}_{L}\ifmmode\times\else\texttimes\fi{}\mathrm{U}(1)$ electroweak model we find that neutrinos naturally acquire only Dirac masses at tree level, and for an odd number of lepton families, one neutrino remains massless. After a spontaneous breakdown of symmetry we find that the SU(2)\ifmmode\times\else\texttimes\fi{}U(1) effective theory has lepton-number-violating currents which couple to the standard gauge bosons. Flavorconserving $|\ensuremath{\Delta}l|=2$ processes such as neutrinoless double-$\ensuremath{\beta}$ decay are forbidden in the simplest model,…

Measurement of the absolute branching fraction of D + → K̅ 0 e + ν e via K̅ 0 → π 0 π 0

2016

By analyzing 2.93 fb(-1) data collected at the center-of-mass energy root s = 3.773 GeV with the BESIII detector, we measure the absolute branching fraction of the semileptonic decay D+ -> (K) over bar (0)e(+)nu(e) to be B(D (+) -> (K) over bar (0)e(+)nu(e)) = (8.59 +/- 0.14 +/- 0.21)% using (K) over bar (0) -> K-S(0) -> pi(0) pi(0), where the first uncertainty is statistical and the second systematic. Our result is consistent with previous measurements within uncertainties..

Measurements of the semileptonic decaysB¯→Dℓν¯andB¯→D*ℓν¯using a global fit toDXℓν¯final states

2009

Semileptonic (B) over bar decays to DXl (nu) over bar (l = e or mu) are selected by reconstructing D(0)l and D(+)l combinations from a sample of 230 x 10(6) Y(4S) --> B (B) over bar decays recorded with the BABAR detector at the PEP-II e(+)e(-) collider at SLAC. A global fit to these samples in a three-dimensional space of kinematic variables is used to determine the branching fractions B(B- --> D(0)l (nu) over bar = (2.34 +/- 0.03 +/- 0.13)% and B(B- --> D*(0)l (nu) over bar) = (5.40 +/- 0.02 +/- 0.21)% where the errors are statistical and systematic, respectively. The fit also determines form-factor parameters in a parametrization based on heavy quark effective theory, resulting in rho(2)…

Measurements of branching fractions, rate asymmetries, and angular distributions in the rare decays B→K + - and B→K* + -

2006

We present measurements of the flavor-changing neutral current decays B -> K center dot(+)center dot(-) and B -> K-*center dot(+)center dot(-), where center dot(+)center dot(-) is either an e(+)e(-) or mu(+)mu(-) pair. The data sample comprises 229x10(6) Upsilon(4S)-> B (B) over bar decays collected with the BABAR detector at the PEP-II e(+)e(-) storage ring. Flavor-changing neutral current decays are highly suppressed in the standard model and their predicted properties could be significantly modified by new physics at the electroweak scale. We measure the branching fractions B(B -> K center dot(+)center dot(-))=(0.34 +/- 0.07 +/- 0.02)x10(-6), B(B -> K-*center dot(+)center dot(-))=(0.78(-…