$X(3872)$ as virtual companion pole of the charm-anticharm state ${\chi }_{c1}(2P)$

Francesco Giacosa, Milena Piotrowska, Susana Coito

We study the spectral function of the axial-vector charmonium state ${\chi }_{c1}(2P)$ coupled to $D{D}^{\ast }$ mesons, by employing a quantum field theoretical approach: a pronounced enha…