Related papers: Gluonic Mesons in J/Psi Radiative Decay
Rare radiative decay $\phi\to\eta\pi^0\gamma$ was studied with SND detector at {VEPP-2M} electron-positron collider and its branching ratio was measured: $B(\phi\to\eta\pi^0\gamma)=(0.88\pm0.14\pm0.09)\cdot 10^{-4}$. Significant…
The composition of the eta and eta' mesons has long been a source of discussion and is of current interest with new experimental results appearing. We investigate what can be learnt from a number of different processes: V to P gamma and P…
The spin-exotic hybrid meson $\pi_{1}(1600)$ is predicted to have a large decay rate to the $\omega\pi\pi$ final state. Using 76.6~pb$^{-1}$ of data collected with the GlueX detector, we measure the cross sections for the reactions $\gamma…
The pseudoscalar meson eta_b has been searched for in two-photon interactions at LEP II. The data sample corresponds to a total integrated luminosity of 617 pb^{-1} at centre-of-mass energies ranging from 161 to 209 GeV. Upper limits at a…
We study the production of the light $J^{PC}=1^{-+}$ hybrid isoscalars $\eta_1^\prime(1855)$ and the yet undiscovered $\eta_1^{hyb}(1660)$ as intermediate states in the radiative decays of the charmonium ($J/\psi$) to two conventional…
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…
It is reported on a leading-twist analysis of the eta - photon and eta' - photon transition form factors. The analysis allows for an estimate of the lowest Gegenbauer coefficients of the quark and gluon distribution amplitudes.
The $J/\psi$ meson has negative $G$-parity so that, in the limit of isospin conservation, its decay into $\pi^+\pi^-$ should be purely electromagnetic. However, the measured branching fraction $\mathcal{B}(J/\psi\to\pi^+\pi^-)$ exceeds by…
Signal of the rare radiative decay PHI--->ETA+PI0+GAMMA was observed in the SND experiment at VEPP-2M electron-positron collider.The result is based on the analysis of data, corresponding to a total integrated luminosity of 4 pb^{-1}, or…
The observed inclusive decay of B-mesons into eta' + X is interpreted as the consequence of the gluonic decay of the b-quark into an s-quark. As a result of the QCD anomaly this decay proceeds partly as the decay b ---> s + eta', similar to…
We develop tools to determine the gluonic content of a resonance of known mass, width and $J^{PC}$ from its branching fraction in radiative quarkonium decays and production cross section in $\gamma \gamma$ collisions. We test the procedures…
Electromagnetic interactions of the ground and first radial excited states of $\eta$ and $\eta'$ mesons in the framework of the extended $U(3)\times U(3)$ NJL model are considered. The radial excitations are described with the help of…
Details of the analysis of the eta pi- system studied in the reaction pi^{-} p --> eta pi^{-} p at 18 GeV/c are given. Separate analyses for the 2 gamma and pi+ pi- pi0 decay modes of the eta are presented. An amplitude analysis of the data…
With the recent investigations of $g^{\ast}g^{\ast}-\eta^{(\prime)}$ transition form factor and $\eta-\eta^{\prime}$ mixing scheme, we present an updated study of the radiative decays $J/\Psi\to\eta^{(\prime)}\gamma$ in perturbative QCD.…
The background due to the direct diffractive dissociation of the photon into the $\pi^+\pi^-$-pair to the "elastic" diffractive $\rho^0$-meson production in electron-proton collisions is calculated. The amplitude for the background process…
Based on a sample of $1.31$ billion $J/\psi$ events collected with the BESIII detector, we report the study of the doubly radiative decay $\eta^\prime\to \gamma\gamma\pi^0$ for the first time, where the $\eta^\prime$ meson is produced via…
The exploration of exotic mesons, which transcend the conventional quark-antiquark framework, is pivotal for advancing our understanding of QCD and the strong interaction. Among these, states possessing the quantum numbers $J^{PC}=1^{-+}$,…
The two-photon width $\Gamma_{\gamma\gamma}$ of the $\eta_c$ meson has been measured with the L3 detector at LEP. The $\eta_c$ is studied in the decay modes $\pi^+\pi^-\pi^+\pi^-$, $\pi^+\pi^-$K$^+$K$^-$, K$_s^0$K$^\pm\pi^\mp$,…
Using the recently proposed $gg --> eta'$ effective vertex, we investigate the production of $\eta'$ from gluon fusion in $pA$ collisions. We show that measuring $\eta'$ production cross-section at moderate $x_{\eta'}$ yields direct…
We study the decays of the pseudotensor mesons $[ \pi_{2}(1670) , K_{2}(1770) , \eta_{2}(1645) , \eta_{2}(1870) ]$ interpreted as the ground-state nonet of $1^1 D_{2}$ $\bar{q}q$ states using interaction Lagrangians which couple them to…