Related papers: K_{l4} decays
The branching fractions of the decays $\tau \to a_{1} \pi \nu_\tau$, $\tau \to K_{1} \pi \nu_\tau$ and $\tau \to K_{1} K \nu_\tau$ are calculated in the framework of the extended $U(3)\times U(3)$ chiral Nambu--Jona-Lasinio model. There are…
We analyze the dominant decay mechanisms in the radiative decays D -> V gamma, D -> P(V) l+ l-, D -> gamma gamma, D -> l+ l- gamma, and we discuss possible chances to observe the effects of new physics in these decays. Then we comment on…
We use heavy quark effective theory (HQET) and perturbative QCD to study the heavy meson -- light vector meson transitions involved in D and B decays. HQET is used to relate the measured D -> K* l nu vector and axial-vector form factors at…
Observing the mass shifts of chiral partners will provide invaluable insight into the role of chiral symmetry breaking in the generation of hadron masses. Because both the $K^*$ and $K_1$ mesons have vacuum widths smaller than 100 MeV, they…
The $K\to\pi\pi$ decay amplitudes are studied within the framework of generalized factorization in which the effective Wilson coefficients are gauge-invariant, renormalization-scale and -scheme independent while factorization is applied to…
We present the first lattice QCD determination of the $\Lambda \to N$ vector and axial-vector form factors, which are essential inputs for studying the semileptonic decay $\Lambda \to p \ell \bar{\nu}_\ell$. This channel provides a clean,…
Axion models with generation-dependent Peccei-Quinn charges can lead to flavor-changing neutral currents, thus motivating QCD axion searches at precision flavor experiments. We rigorously derive limits on the most general effective…
We consider rare semileptonic decays of a heavy $D$-meson into a light vector meson in the framework of QCD factorization. In contrast to the corresponding $B$-meson decays, the naive factorization hypothesis does not even serve as a first…
Within the framework of chiral effective field theory, we study various electromagnetic processes with light vector resonances: $K^{\ast}(892)\to K\gamma$, $e^{+}e^{-}\to K^{\ast}(892)K $ and the $\omega\pi\gamma^\ast$ form factors. With…
Cabibbo-allowed charmed meson decays into a pseudoscalar meson and an axial-vector meson are studied. The charm to axial-vector meson transition form factors are evaluated in the Isgur-Scora-Grinstein-Wise quark model. The dipole momentum…
Charmless 3-body decays of $B$ mesons are studied using a simple model based on the framework of the factorization approach. We have identified a large source of the nonresonant signal in the matrix elements of scalar densities, e.g.…
We present an exploratory study of the $\Lambda_{c,b}\to N^*$-form factors and the semileptonic decay width within the framework of light-cone sum rules. We use two different methods and two different interpolating currents for the…
The fully differential angular distribution for the rare flavor-changing neutral current decay {\bar B}_d^0 -> {\bar K}^{*0} (-> K^- \pi^+) e+ e- is studied. The emphasis is placed on accurate treatment of the contribution from the…
The transition form factors describing the semileptonic decays of heavy pseudoscalar mesons are investigated within a relativistic constituent quark model formulated on the light-front. For the first time, the form factors are calculated in…
The form factor $g_{\rho \pi}^{(S)}(Q^{2})$ of the strange vector current transition matrix element $<\rho| \bar{s}\gamma_\mus|\pi>$ is calculated within the chiral quark model. A strange vector current of the constituent $U$- and D-quarks…
Using Chiral Perturbation Theory to properly account for the dynamics of nonleptonic $K\to 2\,\pi$ decays, we found the Standard Model prediction for the CP violating ratio $\mbox{Re}\left(\varepsilon'/\varepsilon\right)=\left(14\pm…
The data on the form factors of the $K_{e4}$ decay permit to fix a value of the non-specified in the theory parameter entering in the lagrangian of the system of $0^+$ and $0^-$ mesons . Then, for a mass of the lightest $\sigma$-meson we…
We investigate the electroweak form factors and semileptonic decay rates of pseudoscalar and vector mesons using the light-front constituent quark model. Our method of analytic continuation in the Drell-Yan-West (q^+=q^0+q^3=0) frame to…
Finite energy sum rules for vector and axial-vector currents are derived in a thermal medium to provide constraints for the spectral behavior of rho and a1 mesons at nonvanishing temperature and hence to study the tendency toward chiral…
B meson rare decays ($B\to K(K^{*})l\bar l$ and $B\to K^*\gamma$) are analyzed in the framework of effective field theory of heavy quarks. The semileptonic and penguin type form factors for these decays are calculated by using the light…