Partial wave analysis of $\ddot{I}ˆ(2S)\to p\bar{p}\hat{I}\cdot$

Abstract

Using a sample of $1.06\times 10^8$ $\ddot{I}ˆ(2S)$ events collected with the BESIII detector at BEPCII, the decay $\ddot{I}ˆ(2S)\to p\bar{p}\hat{I}\cdot$ is studied. A partial wave analysis determines that the intermediate state N(1535) with a mass of $1524\pm 5_{-4}^{+10}$ MeV/$c^2$ and a width of $130_{-24-10}^{+27+57}$ MeV/$c^2$ is dominant in the decay; the product branching fraction is determined to be $B(\ddot{I}ˆ(2S)\to N(1535)\bar{p})\times B(N(1535)\to p\hat{I}\cdot )+c.c.=(5.2\pm 0.3_{-1.2}^{+3.2})\times 10^{-5}$. Furthermore, the branching fraction of $\ddot{I}ˆ(2S)\to \hat{I}\cdot p\bar{p}$ is measured to be $(6.4\pm 0.2\pm 0.6)\times 10^{-5}$.