Unquenched Radially Excited \(P\)-wave Charmonia

The ground-state positive-parity charmonia \(χ c0(1P)\), \(χ c1(1P)\), \(h_c(1P)\), and \(χ c2(1P)\) are generally well described in static (“quenched”) quark models, in which dynamical effects of actual or virtual strong decay are neglected. In contrast, the five PDG candidates for \(P\)-wave charmonia in the energy region of 3.85–3.95 GeV, probably including the first radial excitations of the above ones, display a totally different and quite disparate mass pattern. Moreover, two scalar states are listed, viz. \(χ c0(3860)\) and \(χ c0(3915)\), the former one apparently being very broad. Preliminary results will be presented here for the first radial excitations of the lowest \(P\)-wave \(cc̄\) states, obtained with the Resonance-Spectrum Expansion while including in the calculation all OZI-allowed decay channels of the most relevant charm-meson pairs. Employing a generalised scheme of computing coupling constants for decays based on the \({}3\!P_0\) model ensures that no distortion of the spectra will occur due to the different classes of allowed decay channels for the various positive-parity charmonia. Abstract Published by the Jagiellonian University 2026 authors