Search for an enhanced production of low energy pions in C(p, π+)X, Cu(p, π+)X, and Cu(p, π∘)X reactions for 300 MeV≦Tp≦400 MeV

The observation of an enhancement in the production of low energy pions in the Cu(p, π+)X reaction is confirmed. The width of the bump is about 5 MeV around 350 MeV. A similar enhancement appears at 330 MeV for C(p, π+)X but the width has not been measured. An attempt to observe this behaviour in Cu(p, π∘)X is described. From the data one cannot conclude about the existence of a structure around 350 MeV proton energy. The lack of resolution in theπ∘ spectrometer may have washed out the small effect expected fromπ+ measurements.