Related papers: Mixing effects of $\eta-\eta'$ in $\Lambda_b\right…
We report branching fractions and CP asymmetries for $B \to \eta K^*$ and $B \to \eta \rho$ decays. These results are obtained from a $414 {\rm fb}^{-1}$ data sample collected at the $\Upsilon(4S)$ resonance, with the Belle detector at the…
In the standard model, CP asymmetries in the $B^\pm \to \pi^\pm K$ channels are about 2% based on perturbative calculation. Rescattering effects might enhance it to at most (20-25)%. We show that lepton-number-violating $\lambda'$ couplings…
We present an improved measurement of the $\eta'$ meson energy spectrum in $\Upsilon(1S)$ decays, using 1.2 fb^{-1} of data taken at the $\Upsilon(1S)$ center-of-mass energy with the CLEO III detector. We compare our results with models of…
In this paper, we calculated the $B \to (\jpsi, \eta_c) K$ decays in the perturbative QCD approach with the inclusion of the partial next-to-leading order (NLO) contributions. We found that (a) when the large enhancements from the known NLO…
We investigate what can be learnt about the $\eta$ -$\eta'$ mixing by means of dispersive representation of axial anomaly. We show that our method leads to the strong bounds for the $\eta-\eta'$ mixing angle: $\theta = -15.3^o \pm 1^o$.…
We calculate the branching ratio of $\bar{B}^0 \to \Lambda_c^+ \bar{p}$ in the PQCD approach. Most previous model calculations obtained branching ratios significantly larger than experimental data. We find that the predicted branching ratio…
We study the singly-Cabibbo-suppressed decays $\Lambda_c^{+}\to p\eta$ and $\Lambda_{c}^{+}\to p\pi^{0}$ using $\Lambda_{c}^{+}\Lambda_{c}^{+}$ pairs produced by $e^+e^-$ collisions at a center-of-mass energy of $\sqrt{s} = 4.6\; GeV$. The…
We study the $B^- \to K^- \eta \eta_c$ decay by taking into account the $S$-wave contributions from the pseudoscalar meson-pseudoscalar meson interactions within the unitary coupled-channel approach, where the $D\bar{D}$ bound state is…
We study the $B_{c}$$\rightarrow$$\psi(2S)$K, $\eta_{c}(2S)$K, $\psi(3770)$K decays with perturbative QCD approach (pQCD) based on $k_T$ factorization. The new orbitally excited charmonium distribution amplitudes $\psi(1^{3}D_{1})$ based on…
In the framework of perturbative QCD approach, we calculate the branching ratio and CP asymmetry for $B_{s}^0(\bar{B}_{s}) \to \pi^{\pm} K^\mp$ and $B_{s}(\bar{B}_{s})\to \pi^{0}\bar{K}^{0}(K^{0})$ decays. Besides the usual factorizable…
The octet-singlet $\eta -\eta^{\prime}$ mixing mass term could have a derivative $O(p^{2})$ term as found in recent analysis of the $\eta -\eta^{\prime}$ system. This term gives rise to an additional momentum-dependent pole contribution…
We investigate the rare baryonic exclusive decays of $\Lambda_b\to \Lambda l^+ l^- (l=e,\mu,\tau)$ with polarized $\Lambda $. Under the approximation of the heavy quark effective theory (HQET), in the standard model we derive the…
We investigate the impact of the intrinsic heavy quark states on the predicted values of CP asymmetries in the decays of heavy mesons. It is shown that the intrinsic charm contribution, although dynamically suppressed in QCD, is favored by…
We use QCD sum-rules to study the decays $\phi \to \eta \gamma$ and $\phi \to \eta^\prime \gamma$, obtaining ${\cal B}(\phi \to \eta \gamma)=(1.15 \pm 0.2) 10^{-2}$ and ${\cal B}(\phi \to \eta^\prime \gamma)=(1.18 \pm 0.4) 10^{-4}$, in very…
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 $\eta$…
The first observation of the decay $\eta_{c}(2S) \to p \bar p$ is reported using proton-proton collision data corresponding to an integrated luminosity of $3.0\rm \, fb^{-1}$ recorded by the LHCb experiment at centre-of-mass energies of 7…
We analyse the two purely isospin-violating decays $\Lambda_b\rightarrow \Sigma^0 \phi$ and $\Lambda_b\rightarrow \Sigma^0 J/\psi$, proceed merely via the exchange topologies, in the framework of perturbative QCD approach. Assuming…
We report measurements of $B$ to pseudoscalar-pseudoscalar decays with at least one eta meson in the final state using 140 fb^{-1} of data collected by the Belle detector at KEKB e^+ e^- collider. We observe the decays of B^+-> eta pi^+ and…
The nonet symmetry scheme seems to describe rather well the masses and $\eta-\eta^{\prime}$ mixing angle of the ground state pseudo-scalar mesons. It is expected that nonet symmetry should also be valid for the matrix elements of the…
The $\eta$-$\eta^\prime$ mixing angle is deduced from an updated phenomenological analysis of $J/\psi$ decays into a vector and a pseudoscalar meson. Corrections due to non-ideal $\omega$-$\phi$ mixing are confirmed to be crucial to find…