Related papers: Pion Beta Decay and CKM Unitarity
The \Delta I = 3/2 K to pi pi decay amplitude is calculated on RBC/UKQCD 32^3 times 64, L_s=32 dynamical lattices with 2+1 flavours of domain wall fermions using the Dislocation Suppressing Determinant Ratio and Iwasaki gauge action. The…
Utilizing all the experimental measured charmless $B \to PP$, $PV$ decay modes, where $P(V)$ denotes a light pseudoscalar (vector) meson, we extract the CKM angle $\gamma$ by global fit. All the unknown hadronic parameters are fitted with…
We present our result for the $K\to\pi\pi$ decay amplitudes for both the $\Delta I=1/2$ and $3/2$ processes with the improved Wilson fermion action. In order to realize the physical kinematics, where the pions in the final state have finite…
We determine the ratio FK/Fpi in QCD with Nf=2+1 flavors of sea quarks, based on a series of lattice calculations with three different lattice spacings, large volumes and a simulated pion mass reaching down to about 190 MeV. We obtain…
We study the decays $\pi^{+}\to l^{+}\nu_{l}$ in the presence of a background electromagnetic plane wave with circular polarization. We find that, in the presence of this background, the number of hadronic form factors required to describe…
The rare pion decays ${\pi}^+{\rightarrow}{\mu}^+{\nu}_{\mu}{\nu}\bar{\nu}$ and ${\pi}^+{\rightarrow}e^+{\nu}_{e}{\nu}\bar{\nu}$ are allowed in the Standard Model but highly suppressed. These decays were searched for using data from the…
Superallowed $0^+ \to 0^+$ nuclear beta decay provides a direct measure of the weak vector coupling constant, $\GV$. We survey current world data on the nine accurately determined transitions of this type, which range from the decay of…
We present an exploratory lattice QCD calculation of the neutrinoless double beta decay $\pi\pi\to ee$. Under the mechanism of light-neutrino exchange, the decay amplitude involves significant long-distance contributions. The calculation…
Superallowed $0^+ \to 0^+$ nuclear beta decay provides a direct measure of the weak vector coupling constant, $\GV$. We survey current world data on the nine accurately determined transitions of this type, which range from the decay of…
We propose a method to determine the CKM matrix element $|V_{ub}|$ using the global $q^2$ dependence of the dispersive bound on the form factors for $B\to \pi l\nu$ decay. Since the lattice calculation of the $B\to \pi l\nu$ form factor is…
The pattern of chiral symmetry breaking is exploited to compute vector and axial-vector pion matrix elements in a uniform magnetic field. Our results are model independent, and thereby constitute low-energy theorems that must be obeyed by…
It is shown that in the framework of GIM model,the parity-violating (PV) $\Sigma^{+}(uus) \Rightarrow p(uud) + \gamma $ decay amplitude does not vanish but just transforms into another PV decay amplitude, namely, of the…
We present a study for the pion decay constant $f_\pi$ in the quenched approximation to lattice QCD with the Kogut-Susskind (KS) quark action, with the emphasis given to the renormalization problems. Numerical simulations are carried out at…
We extend recently developed methods used for determining the electromagnetic charge radius and $a_\mu^{\pi\pi}$ to obtain a determination of the electromagnetic form factor of the pion, $F_\pi^V(t)$, in several significant kinematical…
The electromagnetic pion form factor, $F_\pi(q^2)$, is calculated for spacelike-$q^2$ in impulse approximation using a confining quark propagator, $S$, and a dressed quark-photon vertex, $\Gamma_\mu$, obtained from realistic,…
The first lattice QCD calculation of the form factors governing $\Lambda_c \to \Lambda \ell^+ \nu_\ell$ decays is reported. The calculation was performed with two different lattice spacings and includes one ensemble with a pion mass of…
The determination of the angle $\gamma$ of the unitarity triangle of the CKM matrix is regarded as a challenge for future $B$-physics experiments. In this context, the decays $B^\pm\to \pi^\pm K$ and $B_d\to\pi^\mp K^\pm$, which were…
The influence of strong and electroweak penguin amplitudes in $B/ \bar B \rightarrow \pi^+\pi^-$ is investigated in connection with the determination of the unitarity triangle angle $\alpha$ of the CKM matrix. A relation between the…
All relevant inputs for the extraction of the CKM matrix element \vus from \kl, \ks and \kpm decays have been measured at KLOE. From a global fit using only KLOE results, but \ks lifetime, a value of $|\vus|\fzero = 0.2157 \pm 0.0006$ is…
Phases of elements of the Cabibbo-Kobayashi-Maskawa (CKM) matrix can be obtained using decays of $B$ mesons to $\pi^+ \pi^-$, $\pi^\pm K^\mp$, and $\pi^+ K^0$ or $\pi^- \overline{K}^0$. For $B^0~{\rm or}~ \overline{B}^0 \to \pi^+ \pi^-$,…