arXiv subjects
Publications and source records attributed to F. Q. Wu.
We carry out a theoretical and Monte Carlo study on the $J/ψ$ decays into $ωππ$ and $K\bar{K}π$ through intermediate subthreshold $ρ$ meson by using SU(3)-symmetric Lagrangian approach. It is found that the subthreshold $ρ$ contribution is not negligible and may have significant influence on partial wave analysis of resonances in these channels, especially near the $ωπ$ and $K \bar{K}$ thresholds.
We study coupled channel effects upon isospin I=2 and I=0 $ππ$ S-wave interaction. With introduction of the $ππ\toρρ\toππ$ coupled channel box diagram contribution into $ππ$ amplitude in addition to $ρ$ and $f_2 (1270)$ exchange, we reproduce the $ππ$ I=2 S-wave and D-wave scattering phase shifts and inelasticities up to 2 GeV quite well in a K-matrix formalism. For I=0 case, the same $ππ\toρρ\toππ$ box diagram is found to give the largest contribution for the inelasticity among all possible coupled channels including $ππ\toωω\toππ$, $ππ\to K \bar{K}\toππ$. We also show why the broad $σ$ appears narrower in production processes than in $ππ$ scattering process.
A correct understanding and description of the I=2 pi-pi S-wave interaction is important for the extraction of the I=0 pi-pi S-wave interaction from experimental data and for understanding the I=0 pi-pi S-wave interaction theoretically. With t-channel rho, f2(1270) exchange and the pi pi -> rho rho -> pi pi box diagram contribution, we reproduce the pi-pi isotensor S-wave and D-wave scattering phase shifts and inelasticities up to 2.2 GeV quite well in a K-matrix formalism.
With t-channel rho, f2(1270) exchange and the pi pi -> rho rho -> pi pi box diagram contribution, we reproduce the pi pi isotensor S-wave and D-wave scattering phase shifts and inelasticities up to 2.2 GeV quite well in a K-matrix formalism. The t-channel rho exchange provides repulsive negative phase shifts while the t-channel f2(1270) gives an attractive force to increase the phase shifts for pi pi scattering above 1 GeV, and the coupled-channel box diagram causes the inelasticities. The implication to the isoscalar pi pi S-wave interaction is discussed.