Observation of pseudoscalar and axial vector resonances in π−p→K+K−π0n at 18 GeV

Abstract

The number of pseudoscalar mesons in the mass range from 1400 to 1500 MeV/c2 has been a subject of considerable interest for many years, with several experiments having presented evidence for two closely spaced states. A new measurement of the reaction π−p→K+K−π0n has been made at a beam energy of 18 GeV. A partial wave analysis of the K+K−π0 system shows evidence for three pseudoscalar resonances, η(1295), η(1416), and η(1485), as well as two axial vectors, f1(1285), and f1(1420). Their observed masses, widths and decay properties are reported. No signal was observed for C(1480), an IGJPC=1+1−− state previously reported in φπ0 decay.