相关论文: The cusp effect in eta' --> eta pi pi decays

We report on recent results on the decay of the phi into pi^+ pi^- and phi radiative decays into pi^0 pi^0 gamma and pi^0 eta gamma, which require the consideration of the final state interaction of a pair of mesons in a region inaccessible…

Calculations of eta->pi^0 pi^0 gamma gamma decay in generalized chiral perturbation theory are presented. Tree level and some of next-to-leading corrections are involved. Sensitivity to the deviations from the standard chiral perturbation…

In light of recent high-precision data taken by the BESIII Collaboration, we reconsider the dipion transition $\psi(3686) \rightarrow J/\psi \pi^+\pi^-$. The strong pion-pion final-state interactions are taken into account…

We compute B->K eta' branching ratio using perturbative QCD approach. We show that a triangular relation among amplitudes for B^0->K^0 pi^0, B^0->K^0 eta, B^0->K^0 eta' receives large corrections from SU(3) breaking effects. If experimental…

We discuss $\pi\pi$ scattering in the framework of chiral perturbation theory. In particular, we recall the predictions made some time ago for the threshold parameters and for the phase shift difference $\delta_0^0-\delta_1^1$.

In the framework of an effective chiral theory of mesons, pi K scattering is stydied. The scattering lengths, phase shifts, and cross sections are calculated. Theoretical results agree well with data. There is no new parameter in this…

The production of eta pi - system at low mass by the pi- beam in the Coulomb field of Be nuclei was studied. The cross section of the reaction pi- Be --> eta pi- Be was compared to the experimental data on the decay eta --> pi+ pi- gamma…

We use one-loop chiral perturbation theory (ChPT) to compare lattice results for the K+ to pi+ pi0 decay amplitude with the experimental value. Three systematic effects: quenching, finite-volume effects, and the use of unphysical values of…

It is pointed out that the decay of the recently observed charmonium eta_c^prime resonance, eta_c^prime -> eta_c pi pi is simply related to the well studied decay psi^prime -> J/psi pi pi and can thus be used for absolute normalization of…

It has been argued long ago that eta(b) could be observed through the eta(b) => J/psi(=> mu+ mu-) J/psi(=> mu+ mu-) decay chain. Recent calculations indicate that the width of eta(b) into two J/psi is almost three order of magnitude smaller…

We perform a theoretical study of the $D_s^{+}\to \pi^{+}\pi^{+}\pi^{-}\eta$ decay. We look first at the basic $D_s^{+}$ decay at the quark level from external and internal emission. Then hadronize a pair or two pairs of $q\bar{q}$ states…

The NA48/2 experiment at the CERN SPS collected in 2003 and 2004 large samples of the decays K+- -> pi+ pi- e+- nu (Ke4+-), K+- -> pi0 pi0 e+- nu (Ke400) and K+- -> pi0 pi0 pi+-. From the Ke4+- form factors and from the cusp in the M00^2…

Here we present KLOE results on the phi meson decays in pi0 pi0 gamma, pi+ pi- gamma and eta pi0 gamma, the measurement of the ratio Br(phi to eta' gamma)/Br(phi to eta gamma) with the estimate of the eta' gluonium content and the…

The experimental determination of low energy pi K scattering phase shifts would assist in determining scattering lengths as well as low energy constants of chiral perturbation theory for which sum rules have been constructed. The FOCUS…

The final state interaction of pions in $K_{e4}$ decay allows one to obtain the value of the isospin and angular momentum zero $\pi\pi$ scattering length $a_0^0$.We take into account the electromagnetic interaction of pions and isospin…

We study the hadronic $\eta^{\prime}\to\eta\pi\pi$ decays within the framework of $U(3)_{L}\otimes U(3)_{R}$ Chiral Perturbation Theory including resonance states and the complete one-loop corrections. The amplitude is projected in partial…

Using $(1310.6 \pm 7.0) \times 10^{6}~J/\psi$ events acquired with the BESIII detector at the BEPCII storage rings, the decay $\eta^\prime\rightarrow\pi^+\pi^-\mu^+\mu^-$ is observed for the first time with a significance of 8$\sigma$ via…

We present an assessment of the standard model expectations for the branching ratio of the isotopic spin and G-parity violating decay tau --> eta' pi nu_tau. The estimate is based on a vector and scalar meson dominance parametrization of…

The dispersive approach based only on very general principles, unitarity, analyticity and crossing symmetry, combined with chiral counting enables to construct fully relativistic model-independent representations of the eta and K three-pion…

We study the rho^0 and phi decays into pi^+ pi^- gamma, pi^0 pi^0 gamma and phi into pi^0 eta gamma using a chiral unitary approach to deal with the final state interaction of the M M system. The final state interaction modifies only…