Investigation of a (K π) mass enhancement near 1870 MeV in the reaction K −p → K −π+n at 10 and 16 GeV/ c

Abstract

An enhancement in the (K − π +) mass distribution at 1871 ± 10 MeV with full width of 285 ± 40 MeV is observed in the charge-exchange reaction K −p → K − π +n at 10 and 16 GeV/ c. The energy dependence of its cross section, the shape of the differential cross section d σ/d t and the decay angular distributions are consistent with a production mechanism by pion exchange. No significant enhancement at the same mass is seen in the non-charge exchange reaction K −p → (K π) −p. The experimental evidence is reviewed and it is suggested that there may be more than one K ∗ enhancement in the 1700–1900 mass region.