Related papers: $\eta$ and $\eta^\prime$ Physics at BES-III

The form factors of $B_c\rightarrow\eta_c$ and $B_c\rightarrow J/\psi$ are analyzed in the framework of three-point QCD sum rules. In these analyses, the contributions of the vacuum condensate terms $\langle g_{s}^{2}GG\rangle$ and $\langle…

With a sample of $(10087\pm44)\times10^{6}$ $J/\psi$ events accumulated with the BESIII detector, we analyze the decays $\eta'\rightarrow\pi^+\pi^-l^+l^-(l=e,$ $\mu)$ via the process $J/\psi\rightarrow\gamma\eta'$. The branching fractions…

We have searched for the rare decay of the eta meson $\eta \to e^{+}e^{-}$ using the CLEO II detector. The $\eta$'s were produced in $e^{+}e^{-}$ collisions with 10 GeV center-of-mass energy at the Cornell Electron Storage Ring (CESR). We…

A comprehensive review of weak decays of charmed hadrons ($D^{0/+}$, $D^+_s$ and $\Lambda^+_c$) based on analyses of the threshold data from $e^+e^-$ annihilation in the BESIII experiment is presented. Current experimental challenges and…

We analyse the sensitivity of all experimentally observable asymmetries and energy distributions for the neutron beta-decay with a polarised neutron and unpolarised decay proton and electron and the lifetime of the neutron to contributions…

Using 58 million $J/\psi$ and 14 million $\psi(2S)$ events collected by the BESII detector at the BEPC, branching fractions or upper limits for the decays $J/\psi$ and $\psi(2S) \to \Lambda \bar{\Lambda} \pi^0$ and $\Lambda \bar{\Lambda}…

The low $Q^2$ slopes of the the transition form factors provide a unique method to measure the sizes of the neutral pseudo-scalar mesons, since they do not have electromagnetic form factors. From the slope one obtains the "axial transition…

Expressions for decay amplitudes of B0, B- and Bs mesons to two light pseudoscalar or vector mesons, including isosinglet mesons eta, eta', omega, phi, are obtained using Soft Collinear Effective Theory at LO in 1/mb. These are then used to…

The first observation of the $B^0_s\to\eta'\eta'$ decay is reported. The study is based on a sample of proton-proton collisions corresponding to $3.0$ ${\rm fb^{-1}}$ of integrated luminosity collected with the LHCb detector. The…

We study the rare decays of $B_{s} \to M_s\ell \bar{\ell}$ ($M_s=\eta, \eta',\phi$ and $\ell=\nu,e,\mu,\tau$) in the standard model. With the hadronic form factors evaluated in the light front and constituent quark models, we estimate the…

The sector of decay constants of the octet of light pseudoscalar mesons in the framework of 'resummed' $SU(3)$ chiral perturbation theory is investigated. A theoretical prediction for the decay constant of $\eta$-meson is compared to a…

The decays $J/\psi\to\eta\Sigma^{+}\bar{\Sigma}{}^-$ and $\psi(3686)\to\eta\Sigma^{+}\bar{\Sigma}{}^-$ are observed for the first time, using $(10087 \pm 44)\times 10^{6}$ $J/\psi$ and $(448.1 \pm 2.9)\times 10^{6}$ $\psi(3686)$ events…

Based on a sample of 1.31 billion $J/\psi$ events collected with the BESIII detector, we perform a search for the rare decay $\eta'\rightarrow 4\pi^{0}$ via $J/\psi\rightarrow\gamma\eta'$. No significant $\eta'$ signal is observed in the…

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…

The Crystal Ball at MAMI setup offers an excellent possibility to study decays of the eta and eta' meson. Here, recent results of the Crystal Ball at MAMI experiment from eta meson decays are presented. Furthermore, future perspectives of…

The in-medium properties of $\eta$ mesons are studied in hot and dense isospin asymmetric strange magnetized matter using the chiral SU(3) hadronic mean-field model. The scalar and vector density of baryons are expressed in terms of thermal…

New experimental data are presented on the energy dependence of the total cross sections for the np -> d eta and quasi-two-body pp -> pp eta reactions, where the final diproton is detected at very low excitation energy. Differential cross…

Motivated by the large branching ratios observed for the process $B\to\eta^{\prime}K$, we examine critically all the ingredients that go into estimates of B decays into two light pseudoscalars. Within factorization approximation, we examine…

We analyze the decay of $\eta\rightarrow \ell^+\ell^-(\ell=e, \mu)$ via $J/\psi\rightarrow\gamma\eta'$ and $\eta'\rightarrow\pi^+\pi^-\eta$, based on (10087 $\pm$ 44) $\times$ 10$^{6}$ $J/\psi$ events collected with the BESIII detector at…

In the Standard Model (SM) charmless hadronic decays $B_s^0 \rightarrow \eta^\prime \eta$ proceed via tree-level $b\to u$ and penguin $b\to s$ transitions. Penguin transitions are sensitive to Beyond-the-Standard-Model (BSM) physics…