New limits for the exotic exchange reaction π−p → K+Σ− at 5 and 8 GeV

Measurement of the exotic exchange reaction π−p → K+Σ− has been performed at 5 and 8 GeV, in the −0.015 to −0.13 and −0.009 to −0.15 (GeV/c)2 range of t repectively. We give the value near t = 0 of the differential cross section at 5 GeV, 21−21+76 nb/(GeV/c)2, and an upper limit (< 37 nb/GeV/c)2) at 8 GeV. As a check the measured differential cross section is given at both energies for the reaction π+p → K+Σ+ in the same range of t★★★★Results presented here were included in the thesis of Doctorat d′Etat by M.N. Minard, Orsay, France, 1976..