相关论文: $\eta'\to\gamma\gamma$ and the topological suscept…

An analysis of various radiative $VP\gamma$ decays is performed using the two mixing angle description of the $\eta$-$\eta^\prime$ system. The agreement is excellent. Our results are expressed both in the ``octet-singlet'' and in the…

The singlet pseudoscalar sector of light mesons is investigated in the soft-wall model, a bottom-up approach to the AdS/QCD correspondence. The $\eta^\prime$ mass results from the mixing among the fields dual to the axial current,…

We investigate the rare radiative eta decay modes $\eta\to\pi^+\pi^-\gamma\gamma$ and $\eta\to\pi^0\pi^0\gamma\gamma$ within the framework of chiral perturbation theory at $O(p^4)$. We present photon spectra and partial decay rates for both…

In this paper we study the $\eta'$ in $N_f=2+1+1$ lattice QCD simulations at finite temperature. Results are obtained from the analysis of the gluonic defined topological charge density correlator after gradient flow. Our results indicate…

$\Upsilon(1s)\to\gamma(\eta',\eta, f_2(1270))$ are studied by an approach in which the glueball components of these mesons play dominant role. Strong dependence on quark mass has been found in the decays $(J/\psi,…

We investigate the magnetic dipole decays $V\to P\gamma$ of various heavy-flavored mesons such as $(D,D^*,D_s,D^{*}_s,\eta_c, J/\psi)$ and $(B,B^*,B_s,B^*_s,\eta_b,\Upsilon)$ using the light-front quark model constrained by the variational…

The inclusive and exclusive B decays into the eta' meson plus others are investigated in a model based on the QCD anomaly. The invariant mass distribution is discussed. The constraint of the effective coupling is obtained from the data of…

Lattice QCD allows a first-principles study of QCD with the freedom to vary the number and masses of the quarks. I present results on the flavour singlet correlations (this illuminates OZI violating effects) for mesons. Concentrating on the…

It is shown that the evaluation of the expectation value (EV) of topological charge density over $\theta$-vacuum is reduced to investigation of the Chern-Simons term EV. An equation for this quantity is established and solved. EV of the…

The branching ratio of the electromagnetic rare decays $\eta\to\pi^0\gamma\gamma$ and $\eta^\prime\to (\pi^0,\eta)\gamma\gamma$ are analysed in terms of scalar and vector meson exchange contributions using the frameworks of the Linear Sigma…

Using the trace anomaly and low energy relations, as well as the Witten-Veneziano formula for the mass of the $\eta'$ meson, we have developed a formalism which makes it possible to express the gluon condensate, the topological…

The role of the $U(1)_A$ anomaly in QCD phenomenology is reviewed, focusing on the relation between quark dynamics and gluon topology. Topics covered include a generalisation of the Witten-Veneziano formula for the mass of the $\eta'$, the…

A two mixing angle description of the pseudoscalar decay constants associated to the $\eta$-$\eta^\prime$ system is used to parametrize the theoretical amplitudes of the radiative decays $(\eta,\eta^\prime)\to\gamma\gamma$ and the coupling…

The charmless nonleptonic $B\to \eta K$ decay is an useful probe to test the strong interaction dynamics part of the Standard Model. Within the QCD factorization framework, we analyse this particular decay by using the most recent data of…

The $\mathcal{V}\to\mathcal{P}\gamma$ and $\eta(\eta^\prime) \to \gamma\gamma$ decays are evaluated within a Dyson-Schwinger and Bethe-Salpeter equations framework (here $\mathcal{V}=\{\rho^{\pm},K^{\star\pm},\phi\}$ and…

We consider the branching ratio for the process $t \to c \gamma$ in the context of the General Two Higgs Doublet Model type III. We find that taking into account reasonable values for the parameter $\tan \beta$ is possible to get values of…

We study the form factors of the $\eta_c$ meson in the light-front quark model. We explicitly show that the transition form factor of $\eta_c \to \gamma^* \gamma$ as a function of the momentum transfer is consistent with the experimental…

We present a method of determining weak phase \gamma in the Cabibbo-Kobayashi-Maskawa matrix from decays B->\eta K, \eta' K$ alone. Given a large ratio between color-suppressed and color-allowed tree diagrams extracted from global \pi\pi(K)…

The Dalitz distribution and the effective mass spectrum of the lepton pair produced in the decay $\eta_c\to \gamma \ell^+ \ell^-$, as well as the differential cross sections for the crossed channels $\gamma e^-\to \eta_c e^- $ and $e^+…

We update the theoretical framework for the QCD calculation of transition form factors $\gamma^*\gamma\to\eta$ and $\gamma^*\gamma\to\eta'$ at large photon virtualities including full next-to-leading order analysis of perturbative…