Failure to Observe a Meson Decaying intoπ+π0in the Reactionπ++p→π++π0+pwith 968-MeV/cIncidentπ+

Abstract

In a search for a meson decaying into ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{0}$, we have studied the reaction ${\ensuremath{\pi}}^{+}+p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}+{\ensuremath{\pi}}^{0}+p$ at an incident pion momentum near 1 BeV/c. The dipion mass spectrum of almost 7000 events shows no statistically significant bumps, giving an upper limit of approximately 0.1 mb (99% confidence) for a meson with a width narrower than our dipion mass resolution (about \ifmmode\pm\else\textpm\fi{}10 MeV).