Measurement of Inclusive f_1(1285) and f_1(1420) Production in Z Decays with the DELPHI Detector

摘要

Inclusive production of two (K(K-bar)π)~0 states in the mass region 1.22-1.56 GeV in Z decay at LEP I has been observed by the DELPHI Collaboration. The measured masses and widths are 1274 ± 4 and 29 ± 12 GeV for the first peak and 1426 ± 4 and 51 ± 14 MeV for the second. A partial-wave analysis has been performed on the (K(K-bar)π)~0 spectrum in the mass range; the first peak is consistent with the quantum numbers I~G(J~(PC)) = 0~+(0~(-+)/1~(++)) and the second with I~G(J~(PC)) = 0~+(1~(++)). These measurements, as well as their total hadronic production rates per hadronic Z decay, are consistent with the mesons of the type n(n-bar), where n = {u, d}. The are very likely to be the f_1(1285) and the f_1(1420), respectively.