Related papers: $1/N_c$ approximation and universality of vector m…
It is shown that the processes $e^+ e^- \to \pi^+ \pi^-$ and $\tau^- \to \pi^- \pi^0 \nu_\tau$ can be described in a unified approach in satisfactory agreement with experiment using the vector coupling constant $g_{\rho} = 6$. In this case,…
We suggest a method to determine the product of the coupling constants $g_{\rho\sigma\gamma}g_ {\sigma NN}$, in absolute value and relative sign, through the $t$-dependence of the two possible T-even asymmetries for the photoproduction of…
The value of the $N^*(1535)N\rho$ coupling constant $g_{N^*N\rho}$ derived from the $N^*(1535) \to N\rho \to N \pi \pi$ decay is compared with that deduced from the radiative decay $N^*(1535) \to N \gamma$ using the vector-meson-dominance…
We analyze quark-mass and $1/N_c$ corrections to all of the radiative transitions between the vector-meson nonet and the pseudoscalar-meson nonet within a chiral effective Lagrangian approach. We perform fits of the available coupling…
Recent heavy ion experiments indicate modifications of the $\rho-$meson mass in medium. In the CERES experiments $\rho-$mesons are produced at $\sim$ normal nuclear matter density, where hadrons are more appropriate constituents than…
The cross sections for several $\gamma \gamma \to VV$ processes exhibit strong enhancements near threshold, where $V$ denotes a vector meson. The pattern of these enhancements is not well understood; for example, $\gamma \gamma \to \rho^0…
We summarize the current theoretical and experimental status of the spectral changes of vector mesons ($\rho$, $\omega$, $\phi$) in nuclear medium. Various approaches including QCD sum rules, effective theory of hadrons and bag models show…
We determine the value of the \omega -\rho- \pi mesons coupling (g_{\omega\rho\pi}), in the context of the vector meson dominance model, from radiative decays, the \omega \rightarrow 3\pi decay width and the e^+e^- \rightarrow 3\pi cross…
We report on a relation between the decay constants of \rho-like J^{PC}=1^{--} vector mesons, which arises solely from the perturbative analysis of the VV, TT and VT correlators at order \alpha_s^0 in the large-N_c limit. We find…
The possibility to use the width of the decay $\rho \to e^{+}e^{-}$ to fix the input parameter $g_\rho=5.0$ of the $SU(2) \times SU(2)$ chiral-symmetric Nambu--Jona-Lasinio model is discussed. It is shown that for a consistent simultaneous…
The existing experimental evidence on the vector and axial-vector coupling constants, $G_V$ and $G_A$, for neutron $\beta$-decay exhibits two prominent problems: (i) the unitarity for the first row of the CKM matrix seems violated; (ii) one…
The photoproduction of vector mesons on various nuclei has been studied using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory. The vector mesons, $\rho$, $\omega$, and $\phi$, are observed via their decay to $e^+e^-$,…
The light vector mesons ($\rho$, $\omega$, and $\phi$) were produced in deuterium, carbon, titanium, and iron targets in a search for possible in-medium modifications to the properties of the $\rho$ meson at normal nuclear densities and…
We revisit the experimental and theoretical status of $B \to \rho l \bar{\nu}$ and $B \to \omega l \bar{\nu}$ decays. We perform a combined fit of averaged spectra from Belle and Babar measurements with prior light cone sum rule…
We propose a simple meson-exchange model of the photoproduction of $\rho$- and $\omega$-mesons off protons near threshold ($E_\gamma$ less than 2 GeV). This model provides a good description of the available data and implies a large…
We present results for the coupling of the light vector mesons to the tensor current, relative to the standard vector meson decay constants. From an O(a)-improved lattice study, performed at three values of the lattice spacing in the…
The study of the purely leptonic decays of the ground charged vector mesons is very interesting and significant in determining the CKM matrix elements, obtaining the decay constant of vector mesons, examining the lepton flavor universality,…
Cross sections for the coherent photoproduction of $\rho^{0}$ vector mesons in ultra-peripheral Pb-Pb collisions at $ \sqrt{s_{\mathrm{NN}}}= 5.02$ TeV are reported. The measurements, which rely on the $\pi^+\pi^-$ decay channel, are…
High-statistics total cross sections for the vector meson photoproduction at the threshold: $\gamma p\to\omega p$ (from A2 at MAMI, ELPH, and CBELSA/TAPS), $\gamma p\to \phi p$ (from CLAS and LEPS), and $\gamma p\to J/\psi p$ (from GlueX)…
We present a calculation of full one-loop radiative corrections, including the constant term, to the asymmetry parameter of polarised neutron beta decay. This gives the radiative correction to the axial coupling constant $g_A$ extracted…