相关论文: Form factor in K+ --> pi+ pi0 gamma: interference …

Using a large sample of charm semileptonic decays collected by the FOCUS photoproduction experiment at Fermilab, we present evidence for a small, even spin K- \pi+ amplitude that interferes with the dominant K*0 component in the K-pi+ mu-…

We present a model for the decay $D^+\to K^-\pi^+\pi^+$. The weak interaction part of this reaction is described using the effective weak Hamiltonian in the factorisation approach. Hadronic final state interactions are taken into account…

We determine the magnitude, phase, and $s$-dependence of $\rho$-$\omega$ ``mixing'' in the pion form factor in the time-like region through fits to $e^+e^- \ra \pi^+ \pi^-$ data. The associated systematic errors in these quantities, arising…

The analysis of the $\pi\gamma$ transition form factor provides severe constraints on the pion's wave function. This information is used to examine charmonium decays into two pions critically. It will be argued that the standard…

The recently measured $\gamma\gamma^*\rightarrow \pi^0$ anomalous form factor is analyzed using the $D4/D8\bar{D8}$ holographic approach to QCD. The half-on-shell transition form factor is vector meson dominated and is shown to exactly tie…

Motivated by the ongoing measurements of the Primakoff process pi- gamma* --> pi- pi0 by COMPASS collaboration at CERN, the transition form factor for the canonical anomalous process gamma* --> pi+ pi0 pi- is calculated in a constituent…

We illustrate the progress of covariant QCD phenomenology for the description of meson coupling constants and form factors. As examples, we discuss the $\rho\pi\pi$ and $\gamma \pi\rho$ interactions, the $\rho$ contribution to the pion…

The behaviour of the pion transition form factor for the process $\gamma^\star\gamma \to \pi^0$ and $\gamma^\star\gamma^\star\to \pi^0$ at space-like values of photon momenta is estimated within the nonlocal covariant quark-meson model. The…

The photoproduction p(gamma, K+)Lambda process is studied within a field-theoretic approach. It is shown that the background contributions constitute an important part of the reaction dynamics. We compare predictions obtained with three…

We report on the status of the Fermilab-MILC calculation of the form factor f_+^{K pi}(0), needed to extract the CKM matrix element |V_{us}| from experimental data on K semileptonic decays. The HISQ formulation is used in the simulations…

The electromagnetic form factor for the $K^0$ is calculated in a covariant formulation of the Salpeter equation for $q\bar q$ - bound states, which has been presented recently for the mass spectrum, decay properties and form factors of the…

An intrinsic form factor has benn found and the slope of the form factor has been predicted.

Experimental data on $\pi N $ scattering in the elastic energy region $W \leq 1.45 GeV $ are analyzed within the $K$-matrix approach with effective Lagrangians. The charge splitting in $\delta^{++}_{33} $ and $\delta^{0}_{33}$ phases…

We have applied the light-front formalism to calculate the electromagnetic form factors for the pion and the kaon from two models at low and high energies in order to explore the differences between such models. We have also compared the…

We provide a theoretical update of the calculations of the pi0-gamma*-gamma form factor in the LCSR framework, including up to six polynomials in the conformal expansion of the pion distribution amplitude and taking into account twist-six…

The $\gamma^{*}\rho^0\to\pi^0$ transition form factor is extracted from recent result for the $\gamma^* \gamma^* \pi^0$ form factor obtained in the extended hard-wall AdS/QCD model with a Chern-Simons term. In the large momentum region, the…

In this paper, several calculations of the matrix elements for processes that may contribute to e+ e- --> pi+ pi- pi0 pi0 using the isobar model and the Lorentz invariant amplitude method are presented. The formulas may be used to determine…

We perform a dispersive analysis of the $\omega\pi$ electromagnetic transition form factor, using as input the discontinuity provided by unitarity below the $\omega\pi$ threshold and including for the first time experimental data on the…

The gamma(*) pi(0) -> gamma form factor is obtained within the Lagrangian quark model with separable interaction known to provide a good description of the pion observables at low energies. The pion-quarks vertex is chosen in a Gaussian…

The role of the reaction e+e- --> e+ e-pi+pi- in the pion form factor measurements via radiative return method without photon tagging is studied in detail. The analysis is based on the developed Monte Carlo program EKHARA, which ingredients…