Partial wave analysis of J/psi to p pbar pi0

Abstract

Using a sample of 58 million $J/\ddot{I}ˆ$ events collected with the BESII detector at the BEPC, more than 100,000 $J/\ddot{I}ˆ\to p\bar{p}\ddot{I}{€}^0$ events are selected, and a detailed partial wave analysis is performed. The branching fraction is determined to be $Br(J/\ddot{I}ˆ\to p\bar{p}\ddot{I}{€}^0)=(1.33\pm 0.02\pm 0.11)\times 10^{-3}$. A long-sought `missing' $N^{\ast }$, first observed in $J/\ddot{I}ˆ\to p\bar{n}\ddot{I}{€}^{-}$, is observed in this decay too, with mass and width of $2040_{-4}^{+3}\pm 25$ MeV/c${}^2$ and $230_{-8}^{+8}\pm 52$ MeV/c${}^2$, respectively. Its spin-parity favors ${3/2}^{+}$. The masses, widths, and spin-parities of other $N^{\ast }$ states are obtained as well.

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