相关论文: Light-Meson Two-Photon Decays in Full QCD
We perform a lattice QCD calculation of the \pi^0\to\gamma\gamma transition form factor and the associated decay width. We use a Euclidean time integral of the relevant three-point function to compute the decay amplitude for two-photon…
Two-photon decays of light scalar mesons are discussed within the quarkonium and tetraquark asignements: in both cases the decay rate of the sigma resonances turns out to be smaller than 1 keV.
We present a theoretical framework within which both the real and imaginary parts of the complex, two-photon exchange amplitude contributing to $K_L\rightarrow\mu^+\mu^-$ decay can be calculated using lattice QCD. The real part of this…
We present recent results for meson decay constants calculated on configurations with two flavours of O(a)-improved Wilson fermions. Non-perturbative renormalisation is applied and quark mass dependencies as well as finite volume and…
We argue that charmonium decays into meson pairs fall into two distinct classes: one that is under control of perturbative QCD and another one that is governed by a soft mechanism. We concentrate on a systematic analysis of J/Psi (Psi')…
We perform a lattice QCD study of the $\rho$ meson decay from the $N_f=2+1$ full QCD configurations generated with a renormalization group improved gauge action and a non-perturbatively $O(a)$-improved Wilson fermion action. The resonance…
The leading electromagnetic (e.m.) and strong isospin-breaking corrections to the $\pi^+ \to \mu^+ \nu[\gamma]$ and $K^+ \to \mu^+ \nu[\gamma]$ leptonic decay rates are evaluated for the first time on the lattice. The results are obtained…
One of the open issues in evaluations of the contribution from hadronic light-by-light scattering to the anomalous magnetic moment of the muon $(g-2)_\mu$ concerns the role of heavier scalar, axial-vector, and tensor-meson intermediate…
Isospin is an almost exact symmetry of strong interactions and the corrections to the isosymmetric limit are, in general, at the percent level. For several hadronic quantities relevant for flavour physics phenomenology, such as pseudoscalar…
We report on a two-flavour lattice QCD study of the D_s and D_s^* leptonic decays parameterized by the decay constants f_{D_s} and f_{D_s^*}. As the phenomenology in the D_s sector seems very promising in the next years with the experiments…
We present lattice QCD results for masses and magnetic polarizabilities of light and strange pseudoscalar mesons, chiral condensates, decay constants of neutral pion, and neutral kaon in the presence of background magnetic fields with $eB$…
In this paper, we present results on strong two-body decay widths of light $q\bar q$ mesons calculated in a covariant quark model. The model is based on the Bethe-Salpeter equation in its instantaneous approximation and has already been…
The decay of photon by the influence of magnetic field is considered. It is shown here that if the photon energy is grater than 1 MeV then photon can decay electron positron pair, but if it remains below 1 MeV then photon decays into…
We compute the complex, long-distance two-photon-exchange amplitude which contributes to the rare $K_{\rm L}\rightarrow\mu^+\mu^-$ decay from lattice QCD. We use a $24^3\times 64$ physical-pion-mass gauge field ensemble at an inverse…
We compute the light axial-vector and tensor meson two-photon transition form factors in the soft-wall holographic model of QCD in the flavor-symmetric case. They are used to evaluate the axial-vector and tensor meson contributions to the…
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…
We present some results of the {\bf{ELC}} (European Lattice Collaboration) study of leptonic and semi-leptonic decays of heavy-light mesons. Results on the decay constants $f_D, f_{D_s}$ and $f_B, f_{B_s}$, the semi-leptonic form factors of…
By means of the universal unitary and analytic model of electromagnetic structure of hadrons the two-photon decay rates of P=pi^0, eta, eta' mesons are determined in an alternative way from data on their transition form factors.
A lattice quantum chromodynamics (LQCD) calculation of the nuclear matrix element relevant to the $nn\to ppee\overline{\nu}_e\overline{\nu}_e$ transition is described in detail, expanding on the results presented in Ref. [1]. This matrix…
We construct several classes of hadronic matrix elements and relate them to the low-energy constants in Chiral Perturbation Theory that describe the electromagnetic effects in the semileptonic beta decay of the pion and the kaon. We propose…