Related papers: $\eta-\eta^{\prime}$ mixing
Neutrino mass sum-rule is a very important research subject from theoretical side because neutrino oscillation experiment only gave us two squared-mass differences and three mixing angles. We review neutrino mass sum-rule in literature that…
The branching ratios of dilepton anomalous decays $\eta^{(\prime)}\to\pi^+\pi^-l^+l^-$, where $l=e,\mu$, are calculated in the framework of the Nambu -- Jona-Lasinio model. Particular attention is paid to studying the hadronic perturbative…
The key assumption used recently by Feldmann, Kroll and Stich [Phys.Rev. D58, 114006 (1998)] that the decay constants f_\eta, and f_\eta ' of the respective eta and eta ' mesons in the quark flavor basis follow the pattern of strange and…
We calculate the momentum dependence of the $\rho-\omega$ mixing amplitude in a purely hadronic model. The basic assumption of the model is that the mixing amplitude is generated by $N{\bar{N}}$ loops and thus driven entirely by the…
Eta bound states in nuclei are sensitive to the flavour-singlet component in the eta. The bigger the singlet component, the more attraction and the greater the binding. eta-etaprime mixing plays an important role in understanding the value…
The \eta and \eta' transition form factors in the space-like region are analyzed at low and intermediate energies in a model-independent way through the use of rational approximants. The slope and curvature parameters of the form factors as…
The existing definitions of mixing angles (one-loop radiatively corrected and renormalization-scale-independent) for scalar particles turn out to be gauge-dependent when used in gauge theories. We show that a scale- and gauge-independent…
We have studied the $\tau^-\to K^-\eta^{(\prime)}\nu_\tau$ decays within Chiral Perturbation Theory including resonances as explicit degrees of freedom. We have considered three different form factors according to treatment of final-state…
The $\eta$ and $\eta^\prime$ transition form factors in the space-like region are analyzed at low and intermediate energies in a model-independent way through the use of rational approximants. The slope and curvature parameters of the form…
Using $(1310.6 \pm 7.0) \times 10^{6}~J/\psi$ events acquired with the BESIII detector at the BEPCII storage rings, the decay $\eta^\prime\rightarrow\pi^+\pi^-\mu^+\mu^-$ is observed for the first time with a significance of 8$\sigma$ via…
We study the $\theta$-dependent mass spectrum of the massive $2$-flavor Schwinger model in the Hamiltonian formalism using the density-matrix renormalization group(DMRG). The masses of the composite particles, the pion and sigma meson, are…
The $\eta$-nucleon ($\eta$N) interactions are deduced from the heavy baryon chiral perturbation theory up to the next-to-leading-order terms. Combining the relativistic mean-field theory for nucleon system, we have studied the in-medium…
We study models of neutrino masses which naturally give rise to an inverted mass hierarchy and bi-maximal mixing. The models are based on the see-saw mechanism with three right-handed neutrinos, which generates a single mass term of the…
The minimal Standard Model extension with the Weinberg operator does accommodate the observed neutrino masses and mixing, but predicts a neutrinoless double beta ($0\nu\beta\beta$) decay rate proportional to the effective electron neutrino…
The new CLEO and LEP data on the eta-gamma and eta'-gamma transition form factors have renewed the interest in simple interpolation formulas, valid at any value of momentum transfer. We are going to show that recent theoretical and…
We propose a simple but suggestive seesaw model with two phenomenological conjectures: three heavy (right-handed) Majorana neutrinos are degenerate in mass in the symmetry limit and three light Majorana neutrinos have the tri-bimaximal…
We survey various U_A(1) problems and attempt to resolve the two puzzles related to the eta mesons that have experimental verification. Specifically, we first explore the Goldstone structure of the eta and eta' mesons in the context of…
Instead of the glueball-$\eta'$ mixing ansatz, the latest measured ratios of the branching fractions of $B_{(s)}^0\to J/\psi \eta^{(\prime)}$ decays by LHCb can be understood by including the contribution from the light quark annihilation…
Assuming positive observation of neutrinoless double bata decay together with the CHOOZ reactor bound, we derive constraints imposed on neutrino mixing parameters, the solar mixing angle \theta_{12} and the observable mass parameter < m…
QCD sum-rules are used to calculate the $\hat\rho(1^{-+})\to\pi\eta, \pi\eta'$ decay widths of the exotic hybrid in two different $\eta-\eta'$ mixing schemes. In the conventional flavour octet-singlet mixing scheme, the decay widths are…