A note on the newly observed Y(4220) resonance

TL;DR

This paper discusses the observation of the Y(4220) resonance, proposing it as a tetraquark state with specific quantum numbers, supported by experimental data and theoretical predictions.

Contribution

It identifies the Y(4220) as a diquark-antidiquark tetraquark resonance with L=1, linking two experimental observations and confirming heavy quark spin conservation.

Findings

Y(4220) likely the same state in different channels

Measured branching ratios match tetraquark predictions

Supports tetraquark interpretation of Y(4220)

Abstract

BES III Collaboration has recently observed a vector resonance in the chi_{c0} omega channel, at a mass of about 4220 MeV, named Y(4220). Hints of a similar structure appear in the h_c pi+ pi- channel. We find that the two observations are likely due to the same state, which we identify with one of the expected diquark-antidiquark resonances with orbital quantum number L = 1. This assignment fulfills heavy quark spin conservation. The measured branching fractions ratio into chi_{c0} omega and h_c pi+ pi- is compatible with the prediction for such a tetraquark state.