Related papers: eta and eta' Physics at MAMI
A partial wave analysis of pbar-p -> eta-eta-pizero data from the Crystal Barrel experiment is made in terms of s-channel resonances. The decay channels a_0(980)-eta, f_0(1770)-pi and f_0(2105)-pi provide evidence for two I = 1 J^{PC} =…
A phenomenological analysis on various decay processes is performed using an energy-dependent $\eta-\eta'$ mixing angle scheme. Special attention is given to the radiative couplings between lowest-lying vector and pseudoscalar mesons. The…
The hadronic decays eta -> pi pi pi, eta-prime -> pi pi pi and eta-prime -> eta pi pi are investigated within a U(3) chiral unitary approach. Final state interactions are included by deriving the effective s-wave potentials for meson meson…
We report a search for $B$ decays to selected final states with the $\eta_c$ meson: $B^{\pm}\to K^{\pm}\eta_c\pi^+\pi^-$, $B^{\pm}\to K^{\pm}\eta_c\omega$, $B^{\pm}\to K^{\pm}\eta_c\eta$ and $B^{\pm}\to K^{\pm}\eta_c\pi^0$. The analysis is…
We present further tests and applications of the new eta-eta' mixing scheme recently proposed by us. The particle states are decomposed into orthonormal basis vectors in a light-cone Fock representation. Because of flavor symmetry breaking…
We shed light upon the eta' mass in nuclear matter in the context of partial restoration of chiral symmetry, pointing out that the U_{A}(1) anomaly effects causes the eta'-eta mass difference necessarily through the chiral symmetry…
We present preliminary results for the masses and decay constants of the $\eta$ and $\eta^\prime$ mesons using CLS $N_f = 2+1$ ensembles. One of the major challenges in these calculations are the large statistical fluctuations due to…
One of the basic motivations of the KLOE-2 and WASA-at-COSY experiments is the test of fundamental symmetries and the search for phenomena beyond the Standard Model in the hadronic and leptonic decays of ground-state mesons and in…
A two mixing angle description of the pseudoscalar decay constants associated to the $\eta$-$\eta^\prime$ system is used to parametrize the theoretical amplitudes of the radiative decays $(\eta,\eta^\prime)\to\gamma\gamma$ and the coupling…
A new type of cosmic-ray experiment is under construction in the Pyh\"asalmi mine in the underground laboratory of the University of Oulu, Finland. It aims to study the composition of cosmic rays at and above the knee region. The…
We study the formation and decay of electron-hole droplets in diamonds at both low and high temperatures under different excitations by master equations. The calculation reveals that at low temperature the kinetics of the system behaves as…
The radiative decays of the pseudoscalar mesons $P=(\pi^0,\eta,\eta')$ are of special interest as they provide an experimental window on the electromagnetic and colour chiral $U_A(1)$ anomalies. $\pi^0\to\gamma\gamma$ is well described by…
At ELSA interesting results on baryon resonances have been obtained by the CB-ELSA, the CBELSA/TAPS and the SAPHIR collaborations. New resonances were found, in particular a new $\rm D_{15}(2070)$ decaying into $p\eta$, was recently…
We are going to perform an inclusive spectroscopy experiment of eta' mesic nuclei with the 12C(p,d) reaction to study in-medium properties of the eta' meson. In nuclear medium, the eta' meson mass may be reduced due to partial restoration…
We review some selected experimental results achieved at the synchrotrons CELSIUS in Sweden and COSY in Germany. They concentrate on meson production with emphasis on the underlying quark structure. The project WASA at COSY is discussed and…
In view of the recent experimental developments on the experimental side in the $\eta \to \pi^0 \gamma \gamma$ decay, and the fact that the Particle Data Group in the on line edition of 2007 reports sizable changes of the radiative decay…
We suggest a way to compare the experiments and simulations of electron dechanneling length in bent crystals performed at different energies and different radii. As an example, we compare the SLAC experiment at 3-14 GeV with earlier…
Glueballs are the most straightforward prediction of QCD, yet while they have likely been produced, none has been unequivocally identified. We pursue a backdoor approach through anomalies, and singularly the $\eta$ and $\eta$' which brings…
We present recent results on light mesons based on Dalitz plot analyses of charm decays from Fermilab experiment E791. Scalar mesons are found to have large contributions to the decays studied, $D^+\to K^-\pi^+\pi^+$ and $D^+,…
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…