Ninth Meson withJPC=1++

Abstract

Expected properties of the $D^{\prime }$ (the ninth meson with $J^{\mathrm{PC}}=1^{++}$) include (a) assignment to a weakly mixed SU(3) singlet, predicted by duality; (b) a mass of ∼950 MeV, predicted by superconvergence; (c) decay modes $\eta \pi \pi$ and ${\pi }^{+}{\pi }^{-}\gamma$; and (d) the possibility of a suppressed $\rho$ signal in the ${\pi }^{+}{\pi }^{-}$ spectrum of the ${\pi }^{+}{\pi }^{-}\gamma$ final state, despite the expectation that the pions are in a state with $I=J=1\mathrm{}$. These features suggest that a recently reported meson near the mass with decay modes $\eta \pi \pi$ and ${\pi }^{+}{\pi }^{-}\gamma$ may be a candidate for this state.