Related papers: On the $\eta'$ Gluonic Admixture
$\Upsilon(1s)\to\gamma(\eta',\eta, f_2(1270))$ are studied by an approach in which the glueball components of these mesons play dominant role. Strong dependence on quark mass has been found in the decays $(J/\psi,…
Exclusive hadronic B-meson decays into two-body final states consisting of a light pseudoscalar or vector meson along with an eta or eta' meson are of great phenomenological interest. Their theoretical analysis involves decay mechanisms…
We show that $D\rightarrow P\eta^\prime$ decay amplitudes, where $P=K,\pi,\eta$, cannot be simply related to their $D\rightarrow P\eta$ counterparts with a single $\eta_0$--$\eta_8$ mixing angle. We propose a novel, consistent treatment of…
The unexpectedly large branching ratios for $B\to \eta' K (\eta' X_s)$ decays could be of gluonic origin. We study the implications for $B\to \eta K (\eta X_s)$ and $P K (PX_s)$, where $P$ is the pseudoscalar glueball. In the mechanism…
We review the theory and phenomenology of the axial U(1) problem with emphasis on the role of gluonic degrees of freedom in the low-energy pp -> pp eta and pp -> pp eta' reactions.
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…
Predictions for energy levels, production and decay rate of gluinonia, non-relativistic boundstates of gluinos, are presented. The potential between color-octet constituents is derived in next-to-next-to leading order and one-loop QCD…
The formalism for treating the leading-twist contributions of the two-gluon Fock components occurring in hard exclusive processes that involve eta and eta' mesons is reviewed. The calculation of the eta, eta'--photon transition form factor…
We study the \egg, \egm and \epg decays using an extended three-flavor Nambu-Jona-Lasinio model that includes the 't~Hooft instanton induced interaction. We find that the $\eta$-meson mass, the \egg, \egm and \epg decay widths are in good…
We summarize the different features which show that QCD spectral sum rule analyses of the scalar two- and three-point functions do not favour the $\bar uu+\bar dd$ interpretation of the broad and low mass $\sigma (0.6)$ and emphasize that a…
We present an improved light-cone sum rule analysis of the decay form factors of $D$ and $D_s$ into $\eta$ and $\eta^{\prime}$ and argue that these decays offer a very promissing possibility to determine the leading Fock-state gluonic…
The observation by the CLEO Collaboration of the decays $B^{(+,0)} \to K^{(+,0)} \eta'$ is shown to imply a significant but still uncertain contribution from the flavor-SU(3)-singlet component of the $\eta'$. By comparing the rate for these…
New results going beyond those obtained from isospin and flavor symmetry and subject to clear experimental tests are obtained for effects of FSI in $B^\pm$ decays to charmless strange final states containing neutral flavor-mixed mesons like…
Manifestations of strong and electromagnetic axial anomalies in two-photon decays of $\eta$ and $\eta'$ mesons are studied. Applying dispersive approach to axial anomaly in the singlet current, we obtain an anomaly sum rule containing…
New results going beyond those obtained from isospin and flavor symmetry and subject to clear experimental tests are obtained for effects of FSI in $B^\pm$ decays to final states containing neutral flavor-mixed mesons like $\omega$, $\phi$,…
The results of mixing angle measurement for $\eta'$, $\eta$ mesons generated in charge exchange reactions with $\pi^{-}$ and $K^{-}$ beams are preseneted. When the $\eta'$, $\eta$ mesons are described in nonstrange(NS)--strange(S) quark…
Gluonic degrees of freedom play an important role in the masses of the eta and etaprime mesons. We discuss eta- and etaprime-nucleon and nucleus interactions where this glue may be manifest. Interesting processes being studied in…
We present a calculation of the process B --> D eta' within a heavy-light chiral quark model. We assume that the eta' has a large gluonic component, and its coupling is described via the glue-glue-eta' effective vertex. The main…
The $\eta -\eta^{\prime}$ mixing mass term due to the derivative coupling $SU(3)\times SU(3)$ symmetry breaking term, produces an additional momentum-dependent pole term for processes with $\eta^{\prime}$, but is suppressed in the $\eta$…
Numerical studies of the bulk properties of the quark-gluon plasma reveal a pronounced drop in pressure $p$ compared to energy density $\e$ as the deconfining temperature is approached from above. We show by general thermodynamic reasoning…