Related papers: $1/N_c$ approximation and universality of vector m…

Associative photoproduction of $\omega$-meson and $N^{*}(1440)$ on nucleons, $\gamma+N\to\omega+N^{*}(1440)$, in the near threshold region is investigated in a framework employing effective Lagrangians. Besides $\pi$-exchange in t-channel,…

In this paper, radiative decays $\rho^0 \to \pi^+\pi^-\gamma, \pi^0\pi^0\gamma$ ,$\phi \to K^+K^-\gamma, K^0 \bar{K^0}\gamma$ are studied systematically in the U(3)$_L\timesU(3)_R$ chiral theory of mesons. The theoretical differential…

In the last years much work has been done to learn about the properties of the $\rho$-meson in nuclear matter. In a calculation of the in-medium spectralfunction of the $\rho$ we find that it is strongly modified by baryonic resonances,…

Neutrino oscillations are only observable when the neutrino production, propagation and detection coherence conditions are satisfied. In this paper we consider in detail neutrino production coherence, taking \pi\to \mu \nu \ decay as an…

We compute the difference in decay widths of charged and neutral \rho(770) vector mesons. The isospin breaking arising from mass differences of neutral and charged \pi and \rho mesons, radiative corrections to \rho -> \pi\pi, and the \rho…

We evaluate radiative decays of $\rho$ and $\omega$ going to two neutral mesons, $\pi^{0} \pi^{0}$ and $\pi^{0} \eta$. We use the sequential vector decay mechanisms in addition to chiral loops and $\rho$-$\omega$ mixing. The chiral loops…

We investigate the rare electromagnetic decays of neutral vector mesons (exemplified by $J/\psi$, $\Upsilon$, $\rho^0$, $\omega,\phi$, \ldots) into four charged leptons ($2(e^+e^-)$, $2(\mu^+\mu^-)$, $2(\tau^+\tau^-)$, $e^+e^-\mu^+\mu^-$,…

We study the distribution of lepton pairs from the second lightest neutralino decay \tchi^0_2\to\tchi^0_1 l^+l^-. This decay mode is important to measure the mass difference between \tchi^0_2 and the lightest neutralino \tchi^0_1, which…

In this paper we discuss coherent photo- and leptoproduction of vector mesons from deuterons at intermediate (virtual) photon energies, 3 < nu < 30 GeV. We consider the scattering from unpolarized and polarized targets as well as processes…

The experimental branching ratio for the radiative decay $\rho^{0}\to\pi^{+}+\pi^{-}+\gamma$ is used to estimate the coupling constant $g_{\rho\sigma\gamma}$ for a set of values of $\sigma$-meson parameters M$_{\sigma}$ and…

In the last ten years there has been great progress in calculations of decays of $B$ and $D$ mesons, and baryons containing a heavy $b$ or $c$ quark. One propelling factor has been the measurement of several anomalies in $b\to s$ and $b\to…

Using the close relationship between the low--energy constants of chiral perturbation theory and the chiral invariant interactions of the vector meson resonances with the pseudoscalar mesons, we investigate the process $\rho^0 \ra \pi^+…

This study measured the invariant mass spectra of $\rho$ and $\omega$ mesons in the $e^+e^-$ decay channel for 12 GeV (12.9 GeV/$c$) $p+\mathrm{C}$ and $p+\mathrm{Cu}$ reactions ($\sqrt{s}_{NN}=5.1$ GeV) at the KEK 12-GeV Proton…

Masses and especially coupling constants of the vector meson nonet are determined in the large-N_c limit, but beyond the chiral limit taking into account terms up to quadratic order in the Goldstone boson masses. With two input parameters…

Vector meson photoproduction is an important probe of nuclear structure. Light vector mesons are most sensitive to low$-x$ structure, as long as they are not too light for perturbative QCD calculations. The $\rho'$ is of interest as an…

We present a calculation of $P\to \gamma^{(\ast)}\gamma^{(\ast)}$ processes, where $P=\pi^0,\ \eta,\ \eta'$, at the one-loop level up to and including next-to-next-to-leading order (NNLO) in large-$N_c$ chiral perturbation theory. The…

We present the first and complete dispersion relation analysis of the inner radiative corrections to the axial coupling constant $g_A$ in the neutron $\beta$-decay. Using experimental inputs from the elastic form factors and the…

We explain how angular correlations in leptonic decays of vector bosons and top quarks can be included in Monte Carlo parton showers, in particular those matched to NLO QCD computations. We consider the production of $n$ pairs of leptons,…

A first measurement is presented of exclusive photoproduction of $\rho^0$ mesons associated with leading neutrons at HERA. The data were taken with the H1 detector in the years $2006$ and $2007$ at a centre-of-mass energy of $\sqrt{s}=319$…

A first measurement is presented of exclusive photoproduction of $\rho^0$ mesons associated with leading neutrons at HERA. The data were taken with the H1 detector in the years $2006$ and $2007$ at a centre-of-mass energy of $\sqrt{s}=319$…