Clues for the existence of two K-1(1270) resonances

Abstract

The axial-vector meson K-1(1270) was studied within the chiral unitary approach, where it was shown that it has a two-pole structure. We reanalyze the high-statistics WA3 experiment K(-)p -> K(-)π(+)π(-)p at 63 GeV, which established the existence of both K-1(1270) and K-1(1400), and we show that it clearly favors our two-pole interpretation. We also reanalyze the traditional K-matrix interpretation of the WA3 data and find that the good fit of the data obtained there comes from large cancellations of terms of unclear physical interpretation.