Related papers: $\eta-\eta^{\prime}$ Mixing Angle from Vector Meso…

Mixing angles are used to describe the $SU(6)\otimes O(3)$ symmetry breaking in $\left[70,~1^-\right]$ multiplet in the sector of the lowest mass nucleon resonances, which are investigated extensively in constituent quark models for baryon…

The $\eta$ and $\eta^{\prime}$ mesons are nearly unique in the particle universe since they are almost Goldstone bosons and the dynamics of their decays are strongly constrained. The integrated $\eta$-meson samples collected in earlier…

We present results for the $\eta$ and $\eta^\prime$ masses and their four independent decay constants at the physical point as well as their anomalous gluonic matrix elements $a_{\eta^{(\prime)}}$. The chiral and continuum limit…

An exclusive measurement of the decay eta --> pi+ pi- gamma has been performed at the WASA facility at COSY. The eta mesons were produced in the fusion reaction pd --> 3He X at a proton beam momentum of 1.7 GeV/c. Efficiency corrected…

The ratio of the total exclusive production cross sections for $\eta\prime$ and $\eta$ mesons has been measured in the $pp$ reaction at $p_{beam}=3.67$ GeV/c. The observed $\eta\prime/\eta$ ratio is $(0.83\pm{0.11}^{+0.23}_{-0.18})\times…

An attempt is made to explore the possibility for deviations of solar mixing angle ($\theta_{12}$) from tri-bimaximal mixings, without sacrificing the predictions of maximal atmospheric mixing angle ($\theta_{23}=\pi/4$) and zero reactor…

The effective action of the linear meson model generates the mesonic n-point functions with all quantum effects included. Based on chiral symmetry and a systematic quark mass expansion we derive relations between meson masses and decay…

We analyze power-suppressed contributions to singlet pseudoscalar $\eta$ and $\eta^{\prime}$ meson transition form factors. These corrections stem from endpoint singularities and help improve the agreement between QCD theory and the…

Some claim that there are two independent mixing angles ($\theta = 35.3^\circ$, $-54.7^\circ$) between $^3P_1$ and $^1P_1$ states of heavy-light mesons in heavy quark symmetric limit, and others claim there is only one ($\theta =…

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 determine the possible values of the effective Majorana neutrino mass $|< m > |= |\sum_j U_{ej}^2 m_j|$ in the different phenomenologically viable three and four-neutrino scenarios. The quantities $U_{\alpha j}$ ($\alpha =…

We have measured the radiative decays phi -> eta gamma, phi ->etaprime gamma selecting pi+ pi- gamma gamma gamma final state in a sample of about 5 times 10^7 phi mesons produced at the Frascati phi factory DAFNE. We obtain Gamma(phi ->…

We obtain explicit expressions for the \eta and \eta' masses and decay constants using U_L(3) x U_R(3) chiral perturbation theory at next-to-leading order in a combined expansion in p^2 and 1/Nc. A numerical fit of the parameters appearing…

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…

We study the $B^- \to K^- \eta \eta_c$ decay by taking into account the $S$-wave contributions from the pseudoscalar meson-pseudoscalar meson interactions within the unitary coupled-channel approach, where the $D\bar{D}$ bound state is…

Using $e^+e^-$ annihilation data corresponding to an integrated luminosity of 3.19\,fb$^{-1}$ collected at a center-of-mass energy of 4.178~GeV with the BESIII detector, we measure the absolute branching fractions $\mathcal{B}_{D_s^+…

The production of $\eta$ and $\eta'$ mesons is studied in proton-proton and proton-lead collisions collected with the LHCb detector. Proton-proton collisions are studied at center-of-mass energies of $5.02$ and $13~{\rm TeV}$, and…

The light unflavoured meson $\eta/\eta^{\prime}$ decays are valuable for testing non-perturbative quantum chromodynamics and exploring new physics beyond the Standard Model. This paper describes a series of event generators, including…

Considering a general mass matrix for quasi-degenerate neutrinos and treating the experimentally known oscillation parameters as inputs, we study the correlation between the degenerate mass scale $(m)$ and the mixing angle $\theta_{13}$. We…

The production rate for \eta' in pp ->pp \eta' at rest is calculated in a covariant one boson exchange model, previously applied to study pi^0 and \eta production in NN collisions. The transition amplitudes for the elementary BN -> eta' N…