Related papers: Eta and Eta' physics

The fascinating physics underlying eta and eta-prime mesons can be studied theoretically and experimentally in various contexts. In this presentation we want to turn our attention to two important uncorrelated aspects of this vivid research…

The quest for sources of the simultaneous violation of $C$ and $CP$ symmetry was popular in the 1960s, but has since been neglected for a long time. We revisit the operators that break $C$ and $CP$ for flavor-conserving transitions in both…

The decay $\eta_c(2S)\to\pipieta$ is searched for through the radiative transition $\psi(3686) \to\gamma\eta_c(2S)$ using 448 million $\psi$(3686) events accumulated at the BESIII detector. The first evidence of…

Present and planned experiments motivate new theoretical study of properties of light unflavoured pseudoscalar meson decays. An overview including details on two-loop calculation in SU(3) limit is given.

Using 7.33 fb$^{-1}$ of $e^+e^-$ collision data collected by the BESIII detector at center-of-mass energies between 4.128 and 4.226~GeV, we observe for the first time the decay $D^{\pm}_s\to \omega\pi^{\pm}\eta$ with a statistical…

Rare weak decays of $\eta^\prime\to K\pi$ have been investigated in the framework of the $U(3)$ chiral perturbation theory at the leading order. Our study shows that the branching ratio ${\cal B}(\eta^\prime\to K\pi)$ is of the order of…

The electroproduction of eta and eta' mesons on the proton and the neutron is investigated at tree level within the framework of U(3) chiral perturbation theory. In addition to the Born terms low-lying resonances such as the vector mesons…

We discuss the impact of recent progress in semileptonic D decays on light flavour spectroscopy and estimate mixing parameters in the eta-eta^prime system.

We study exclusive $B_s$ decays to final states with $\eta$ and $\eta^\prime$, induced by the rare $b \to s \ell^+ \ell^-$ and $b \to s \nu \bar \nu$ transitions. Differential decay rates and total branching fractions are predicted in the…

Using a low background data sample of $9.7\times10^{5}$ $J\psi\rightarrow\gamma\eta^\prime$, $\eta^\prime\rightarrow\gamma\pi^+\pi^-$ events, which are 2 orders of magnitude larger than those from the previous experiments, recorded with the…

We present a calculation of the decays $\eta^{(')}\to\pi^+\pi^-\gamma^{(\ast)}$ at the one-loop level up to and including next-to-next-to-leading order (NNLO) in large-$N_c$ chiral perturbation theory. The numerical evaluation of the…

The isospin-breaking decay eta {\to} 3pi is an ideal tool to extract information on light quark mass ratios from experiment. For a precise determination, however, a detailed description of the Dalitz plot distribution is necessary. In that…

Back in the mid eighties, a new branch of investigation which was related to the interaction of eta mesons with nuclei came into existence. It started with the theoretical prediction of possible exotic states of eta mesons and nuclei bound…

Based on a sample of 225.3 million J/\psi events accumulated with the BESIII detector at the BEPCII, the decays of \eta' to pi+pi-l+l- are studied via J/\psi to \gamma\eta'. A clear \eta' signal is observed in the pi+pi-e+e- mass spectrum,…

Recent data on branching ratios for \psi(2S) decays to J/\psi\pi^+\pi^-, J/\psi\pi^0\pi^0 and J/\psi\eta are reviewed. An alternative treatment of data is proposed to get rid of the logical inconsistency which occurs in original…

A study of $B^0$~and $B^0_s$ meson decays into $J/\psi\eta$~and $J/\psi\eta^{\prime}$ final states is performed using a data set of proton-proton collisions at centre-of-mass energies of 7 and 8TeV, collected by the LHCb experiment and…

Simple experimental tests are proposed which can clarify the origin for the anomalously high $\eta'$ appearance in charmless strange final states in $B$ decays and can investigate the the nature of SU(3) symmetry-breaking in weak heavy…

We discuss the eta and eta prime photo- and electroproduction as a way to probe the nucleon resonance structure.

hep-ph/0104081 was put by accident insdead of "replace hep-ph/0101024"(v2). We apologize very much.

A systematic study of the $\eta$-$\eta'$ mixing in Large-$N_c$ chiral perturbation theory is presented with special emphasis on the role of the next-to-next-to-leading-order contributions in the combined momentum, quark-mass, and $1/N_c$…