A possible partner state of the $Y(2175)$

TL;DR

This paper uses QCD sum rules to investigate the structure of the $Y(2175)$, proposing two different currents that may couple to two distinct states, one of which aligns with experimental observations.

Contribution

It introduces two new $ss\bar s\bar s$ interpolating currents with $J^{PC} = 1^{--}$ that may correspond to different physical states related to the $Y(2175)$.

Findings

One current couples to the $Y(2175)$.

The other current suggests a new state about 71 MeV higher.

Experimental evidence supports the existence of the second state.

Abstract

We study the $Y(2175)$ using the method of QCD sum rules. There are two independent $ss\bar s\bar s$ interpolating currents with $J^{PC} = 1^{--}$, and we calculate both their diagonal and off-diagonal correlation functions. We obtain two new currents which do not strongly correlate to each other, so they may couple to two different physical states: one of them couples to the $Y(2175)$, while the other may couple to another state whose mass is about $71 ^{+172}_{-~48}$ MeV larger. Evidences of the latter state can be found in the BaBar, BESII, Belle, and BESIII experiments.