Theoretical study on \eta'--> 4 pions

Abstract

The ${\eta }^{\prime }$ meson is associated with the U(1) anomaly. In this paper, a successful effective chiral theory of mesons has been applied to study the anomalous decay of ${\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}{\pi }^{+(0)}{\pi }^{-(0)}$. In this study, the contributions of triangle and box anomalies are calculated. It is shown that the contribution of box diagrams is important in this process. We predict branching ratios of $Br({\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}{\pi }^{+}{\pi }^{-})=\frac{1}{2}Br({\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}{\pi }^0{\pi }^0)=(8.3\pm 1.2)\times 10^{-5}$, which is in good agreement with BESIII measurement.

Comments: 12 pages, 1 figure, 1 table