Test of the multiquark structure of a1(1420) in strong two-body decays

We present an analysis of strong two-body decays of the a1(1420) with JPC=1++ recently reported by the COMPASS Collaboration at CERN. Following the interpretation of the COMPASS Collaboration that the a1 is an unusual state with a four-quark qq¯ss¯ structure we consider two possible configurations for this state-hadronic molecular and color diquark-antidiquark structures. We find that the dominant decay mode of the a1 is the decay into K and K*. In particular, we calculate that the four decay modes a1→VP with VP=K*±K∓, K*0K¯0, K¯*0K0 together give a dominant contribution to the measured total width of about 150 MeV. The observational mode a1→f0(980)+π0 is significantly suppressed by one order of magnitude.