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 $K^{-}p\to K^{-}{\pi }^{+}{\pi }^{-}p$ 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.

Comments: published version in PRD; typos corrected; title changed to "Clues for the existence of two $K_1(1270)$ resonances"