Radiative and pionic transitions $Z_c(4020{)}^0\to X(3872)\gamma$ and $Z_c(4020{)}^{\pm }\to X(3872){\pi }^{\pm }$

Abstract

The radiative transitions from the neutral exotic $Z_c(4020{)}^0$ resonance to $X(3872)$ with emission of a photon and the pionic transitions from the charged $Z_c(4020{)}^{\pm }$ to $X(3872)$ and a charged pion ${\pi }^{\pm }$ are considered for both charmoniumlike states being charmed meson-antimeson molecules. The underlying processes for these transitions are the decays of the charmed vector meson to pseudoscalar plus a photon or a pion. It is found that the discussed transition rates typically amount to a branching fraction of several permil with a peak at the vector meson pair threshold.

Comments: 9 pages, 4 figures