A QCD sum rule calculation for the Y(4140) narrow structure

TL;DR

This paper uses QCD sum rules to calculate the mass of a potential molecular meson state, finding results consistent with the observed Y(4140) particle, suggesting it could be a $D_s^*ar{D}_s^*$ molecule.

Contribution

The study provides a QCD sum rule calculation supporting the interpretation of Y(4140) as a $D_s^*ar{D}_s^*$ molecular state, including detailed condensate contributions.

Findings

Calculated mass of $D_s^*ar{D}_s^*$ state: 4.14 GeV

Calculated mass of $D^*ar{D}^*$ state: 4.13 GeV

Supports Y(4140) as a molecular state

Abstract

We use the QCD sum rules to evaluate the mass of a possible scalar mesonic state that couples to a molecular $D_{s}^{*}\bar{D}_s^{*}$ current. We find a mass $m_{D_s^*D_s^*}=(4.14\pm 0.09)$ GeV, which is in a excellent agreement with the recently observed Y(4140) charmonium state. We consider the contributions of condensates up to dimension eight, we work at leading order in $\alpha_s$ and we keep terms which are linear in the strange quark mass $m_s$. We also consider a molecular $D^{*}\bar{D}^{*}$ current and we obtain $m_{D^*{D}^*}=(4.13\pm 0.10)$, around 200 MeV above the mass of the Y(3930) charmonium state. We conclude that it is possible to describe the Y(4140) structure as a $D_s^*\bar{D}_s^*$ molecular state.