Search for a Secondπ0

The energy distribution of neutrons from the charge exchange reaction ${\pi }^{-}+p\to {\pi }^0+n$ has been studied, for ${\pi }^{-}$ mesons stopped in liquid hydrogen, to investigate the possible existence of a second ${\pi }^0$ with mass within a few Mev of the mass of "ordinary" ${\pi }^0$. No neutron group corresponding to such a second ${\pi }^0$ was seen. The sensitivity of the measurement was such that a second group of relative intensity above 10-20% would have been seen for any second ${\pi }^0$ with a mass in the range between about $\frac{3}{4}$ Mev and 2 Mev away from the mass of the ordinary ${\pi }^0$.