Could $Z_{c}(3900)$ be a $I^{G}J^{P}=1^{+}1^{+}$ $D^{*}\bar{D}$ molecular state?

TL;DR

This paper uses QCD sum rules to analyze whether the $Z_{c}(3900)$ resonance can be interpreted as a $D^{*}ar{D}$ molecular state with specific quantum numbers, finding a mass consistent with experimental data.

Contribution

It provides a QCD sum rule calculation supporting the molecular state interpretation of $Z_{c}(3900)$ with detailed operator contributions.

Findings

Mass estimate $(3.88 ext{ GeV})$ matches experimental value.

Supports the molecular state hypothesis for $Z_{c}(3900)$.

Uses operator product expansion up to dimension eight.

Abstract

We investigate the nature of the recently observed narrow resonance $Z_{c}(3900)$, which is assumed to be a $D^{*}\bar{D}$ molecular state with quantum numbers $I^{G}J^{P}=1^{+}1^{+}$. Using QCD sum rules, we consider contributions up to dimension eight in the operator product expansion and work at the leading order in $\alpha_{s}$. The mass we arrived at is $(3.88 \pm 0.17) \mbox{GeV}$, which coincides with the mass of $Z_{c}(3900)$.