Discerning the two K1 (1270) poles in D0 →π+VP decay

Abstract

Within the chiral unitary approach, the axial-vector resonance K1(1270) has been predicted to manifest a two-pole nature. The lowest pole has a mass of 1195 MeV and a width of 246 MeV and couples mostly to K∗π, and the highest pole has a mass of 1284 MeV and a width of 146 MeV and couples mostly to ρK. We analyze theoretically how this double-pole structure can show up in D0→π+VP decays by looking at the vector-pseudoscalar (VP) invariant mass distribution for different VP channels, exploiting the fact that each pole couples differently to different VP pairs. We find that the final K̄∗π and ρK̄ channels are sensible to the different poles of the K1(1270) resonance and hence are suitable reactions to analyze experimentally the double-pole nature of this resonance.