$a_1(1260),a_1(1420)$ and the production in heavy meson decays

Wei Wang, Zhen-Xing Zhao

The $a_1(1420)$ with $I^G(J^{PC})=1^{-}(1^{++})$ observed in the ${\pi }^{+}{f}_0(980)$ final state in the ${\pi }^{-}p\to {\pi }^{+}{\pi }^{-}{\pi }^{-}p$ process by the COMPASS collaboration seems unlikely to be an…