Related papers: Electromagnetic axial anomaly in a generalized lin…
We demonstrate how most of the light $J^{P}=0^{+}$ spectrum below $2.0\,\mathrm{GeV}$ and their decays can be consistently described by the unitarized quark model incorporating the chiral constraints of Adler zeros and taking SU(3) breaking…
We have investigated the electromagnetic decays of the antitriplet and sextet charmed baryon systems with $J^P= \frac{1}{2}^+, \frac{3}{2}^+$ in the framework of the heavy baryon chiral perturbation theory. We first construct the chiral…
A multichannel Schr\"odinger equation with both quark-antiquark and meson-meson components, using a harmonic-oscillator potential for $q\bar{q}$ confinement and a delta-shell string-breaking potential for decay, is applied to the…
The lightest scalar and pseudoscalar nonets are discussed within the [A framework of the broken old UxU3 linear sigma model, and it is shown that already at the tree level this model works remarkably well predicting scalar masses and…
The $\eta'$ meson is associated with the U(1) anomaly. In this paper, a successful effective chiral theory of mesons has been applied to study the anomalous decay of $\eta'\rightarrow \pi^+\pi^-\pi^{+(0)}\pi^{-(0)}$. In this study, the…
Attention is paid to the production mechanisms of light scalars that reveal their nature. We reveal the chiral shielding of the \sigma(600) meson. We show that the kaon loop mechanism of the \phi radiative decays, ratified by experiment,…
We study the prospect of measuring the electroweak quantum numbers of beyond the Standard Model (SM) color sextet particles that decay into same-sign top quark pairs. Among these particles, the color sextet scalars give rise to top quarks…
We present the results of computing the $p^6$ order low energy constants in the anomalous part of chiral Lagrangian both for two and three flavor pseudoscalar mesons. This is a generalization of our previous work on calculating the $p^6$…
An extensive and systematic study of the recent eta photoproduction data up to 1.2 GeV is presented within a chiral constituent quark model. A model embodying all known nucleonic resonances shows clear need for a yet undiscovered third S11…
We predict the two-photon width of the pseudoscalar bottomonia, Gamma(eta_b -> gamma gamma), Gamma(eta'_b -> gamma gamma) and Gamma(eta''_b -> gamma gamma) within a Heavy-Quark Spin-Symmetry setting following the same line as our recent…
Dynamical chiral symmetry breaking is described within the linear sigma model of QCD coupled to quarks. The main technical tool used for this intrinsically non--perturbative problem is an exact renormalization group equation for the quantum…
The vector and axial pion-photon transition distribution amplitudes are analyzed in the Spectral Quark Model. We proceed by the evaluation of double distributions through the use of a manifestly covariant calculation based on the alpha…
We present a detailed study of the anomalous single fourth generation $t'$ quark production within the dominant Standard Model(SM) decay modes at future $e^+e^-$ colliders. We calculate the signal and background cross sections in the mass…
Chiral anomaly is a key feature of Lorentz-invariant quantum field theories: in presence of parallel external electric and magnetic fields, the number of massless Weyl fermions of a given chirality is not conserved. In condensed matter,…
The rare decays $\eta^{(\prime)}\to\ell^+\ell^-$, $\ell\in\{e,\mu\}$, are highly suppressed in the Standard Model, both by their chirality structure and the required loop attaching the lepton line to the $\eta^{(\prime)}\to\gamma^*\gamma^*$…
The anomaly-anomaly correlator is studied using QCD sum rules. Using the matrix elements of anomaly between vacuum and pseudoscalars $\pi, eta$ and $\eta'$, the derivative of correlator $chi'(0)$ is evaluated and found to be $\approx 1.82…
We calculate the radiative decay widths of decuplet hyperons in a chiral constituent quark model including electromagnetic exchange currents between quarks. Exchange currents contribute significantly to the E2 transition amplitude, while…
We consider a general N=(2,2) non-linear sigma-model in (2,2) superspace. Depending on the details of the complex structures involved, an off-shell description can be given in terms of chiral, twisted chiral and semi-chiral superfields.…
Anomalous moments of the top quark arises from one loop corrections to the vertices $\bar t t g$ and $\bar t t \gamma$. We study these anomalous couplings in different frameworks: effective theories, Standard Model and 2HDM. We use…
We study the anomalous $\pi^0 \to \gamma\gamma$ decay under an external uniform magnetic field in the framework of a two-flavor Nambu-Jona-Lasinio model. It is seen that the full decay width gets strongly reduced with the external field,…