相关论文: Light-Meson Two-Photon Decays in Full QCD
The extrapolation of the decay amplitudes of the pseudoscalar mesons into two photons from the soft meson limit where it is obtained from the axial-anomaly to the mass shell involves the contribution of the 0^ - continuum. These chiral…
We present results for the QCD matrix elements involved in semi-leptonic decays of B-mesons into pseudo scalar heavy light states. The application of NRQCD heavy quarks allows for quark masses around the physical b-quark. We investigate the…
We revise the radiative corrections to double-Dalitz decays ($P\to\ell\bar{\ell}\ell'\bar{\ell}'$), completing the full next-to-leading order calculation in QED as compared to existing calculations. As a result, we find mild differences…
This thesis deals with the study of properties and interactions of light mesons. Specifically, we focus on hadronic decay and scattering processes, which are dominated by effects of the strong interaction in the low-energy regime. A…
In the presented article we consider exclusive weak decays of doubly heavy baryons with spin $J=1/2$ with production of leptonic pair or a set of light mesons. Using QCD factorization theorem and spectral functions approach we obtain…
The matrix elements of electroweak currents which occur in exclusive decays of heavy hadrons are evaluated in the nonperturbative light-cone Fock representration. In general, each semileptonic exclusive decay amplitude receives two…
The weak decay of the kaon to two pions is studied within the NJL Model. Using the standard effective weak Hamiltonian, both the decay amplitude arising from an intermediate state \sigma-meson and the direct decay amplitude are calculated.…
The ladder-rainbow truncation of the set of Dyson-Schwinger equations is used to study light mesons. The parameters in the effective interaction are constrained by the chiral condensate and f_\pi; the current quark masses are fitted to…
In many calculations of the two--photon decay of hadronic molecules, the decay matrix element is estimated using the wave function at the origin prescription, in analogy to the two-photon decay of parapositronium. We question the…
We present preliminary results for the light harden spectrum in $N_f=2+1$ lattice QCD obtained with the nonperturbatively $O(a)$-improved Wilson quark action and the Iwasaki gauge action. Simulations are carried out at $\beta=1.90$ on a…
The leptonic and semileptonic decays of mesons are investigated within the Domain model of QCD vacuum and hadronization. The Domain Model is the mean-field approach based on the statistical ensemble of almost everywhere homogeneous Abelian…
The leptonic decay-constant ratio $f_K/f_\pi$ is calculated from lattice-QCD simulations using $N_f=2+1$ dynamical fermion flavors in the clover-improved formulation and 2-HEX smearing. The simulations were performed for a range of…
A fully covariant model for describing the electromagnetic decay of Vector Mesons, both in light and in heavy sectors, is presented. The main ingredients of our approach are i) an Ansatz for the Bethe-Salpeter vertex for Vector Mesons, and…
Two-point functions related to the pion weak decay constant $f_\pi$ are calculated from the generating functional of chiral perturbation theory in the mean field approximation and the heavy-baryon limit. The aim is to demonstrate that…
The nonleptonic two body $B_{u,d,s,c}$ decays involving a light tensor meson in final states are studied in the perturbative QCD approach based on $k_T$ factorization. The decay modes with a tensor meson emitted, are prohibited in naive…
In this work, we perform a lattice QCD calculation of the branching ratios and the form factors of radiative leptonic decays $P \to \ell \nu_\ell \gamma$ ($P = \pi, K$) using $N_f=2+1$ domain wall fermion ensembles generated by the RBC and…
The decay of the para-positronium into two photons is studied in the framework of a composite Quantum Field Theoretical approach. This amounts to the evaluation of the electron-positron dressing together with the Weinberg compositeness…
We present an elementary derivation of the width of photon decay in a weak magnetic field using the semiclassical method of worldline instantons. The calculation is generalized to a model of quantum electrodynamics with broken Lorentz…
We report results for the masses of the flavour non-singlet light 0++, 1--, and 1+- mesons from unquenched lattice QCD at two lattice spacings. The twisted mass formalism was used with two flavours of sea quarks. For the 0++ and 1+- mesons…
We use the Mellin-Barnes representation in order to improve the theoretical estimate of mass corrections to the width of light pseudoscalar meson decays into a lepton pair, $P\to l^{+}l^{-}$ . The full resummation of the terms…