On the η 1 (1855), π 1 (1400) and π 1 (1600) as Dynamically Generated States and Their SU(3) Partners.

In this work, we interpret the newly observed η 1 (1855) resonance with exotic J P C = 1 − + quantum numbers in the I = 0 sector, reported by the BESIII Collaboration, as a dynamically generated state from the interaction between the lightest pseudoscalar mesons and axial-vector mesons. The interaction is derived from the lowest order chiral Lagrangian from which the Weinberg–Tomozawa term is obtained, describing the transition amplitudes among the relevant channels, which are then unitarized using the Bethe–Salpeter equation, according to the chiral unitary approach. We evaluate the η 1 (1855) decays into the η η ′ and K K ¯ * π channels and find that the latter has a larger branching fraction. We also investigate its SU(3) partners, and according to our findings, the π 1 (1400) and π 1 (1600) structures may correspond to dynamically generated states, with the former one coupled mostly to the b 1 π component and the latter one coupled to the K 1 (1270) K ¯ channel. In particular, our result for the ratio Γ (π 1 (1600) → f 1 (1285) π) / Γ (π 1 (1600) → η ′ π) is consistent with the measured value, which supports our interpretation for the higher π 1 state. We also report two poles with a mass about 1.7 GeV in the I = 1 / 2 sector, which may be responsible for the K * (1680) . We suggest searching for two additional η 1 exotic mesons with masses around 1.4 and 1.7 GeV. In particular, the predicted η 1 (1700) is expected to have a width around 0.1 GeV and can decay easily into K K ¯ π π . [ABSTRACT FROM AUTHOR]