Two charmoniumlike charged axial resonances near 3885 MeV

TL;DR

The paper proposes that the charged $Z^+_c(3885)$ resonance is actually two closely spaced peaks, caused by isospin violation effects in D and D* meson interactions, which can be tested through specific experimental measurements.

Contribution

It introduces the idea that the $Z^+_c(3885)$ resonance consists of two peaks due to isospin violation, providing a new interpretation of its structure.

Findings

Two peaks are predicted to be separated by at least 1.5 MeV.

The double-peak structure can be observed via shape measurements or isospin-violating transitions.

Isospin violation effects are enhanced by meson mass differences and suppressed forces.

Abstract

It is argued that the charged $Z^+_c(3885)$ resonance, treated as a `molecular' state of charmed $D$ and $D^*$ mesons, is likely to consist of two peaks unequally coupled to the $D^{*+} \bar D^0$ and $D^+ \bar D^{*0}$ channels. The peaks should be split in mass by at least approximately 1.5 MeV. This behavior arises from an enhancement of the effect of isospin violation in the masses of the $D$ and $D^*$ mesons due to apparent suppression of forces between the mesons depending on the spins of the heavy as well as of the light quarks. The suggested double-peak structure can be studied either by direct shape measurement in the channels with heavy mesons, or by isospin-violating transitions from $Z_c^\pm(3885)$ to the states of charmonium plus a light meson.