P-wave Quarkonium Decays to Meson Pairs

TL;DR

This paper investigates P-wave quarkonium decays into meson pairs using non-relativistic QCD and light cone distribution amplitudes, explaining observed violations of helicity rules and predicting measurable decay rates.

Contribution

It introduces the significance of higher twist contributions in P-wave quarkonium decays and explains experimental anomalies with a novel theoretical approach.

Findings

Higher twist effects explain helicity rule violations.

Predicted sizable branching ratio for $oldsymbol{ ext{chi}_{b1} o J/ ext{psi} J/ ext{psi}}$.

Theoretical framework matches recent experimental observations.

Abstract

The processes of P-wave Quarkonium exclusive decays to two mesons are investigated, in which the final state vector mesons with various polarizations are considered separately. In the calculation, the initial heavy quarkonia are treated in the framework of non-relativistic quantum chromodynamics, whereas for light mesons, the light cone distribution amplitudes up to twist-3 are employed. It turns out that the higher twist contribution is significant and provides a possible explanation for the observation of the hadron helicity selection rule violated processes $\chi_{c1}\rightarrow \phi\phi,\omega\omega$ by the BESIII collaboration in recently. We also evaluate the $\chi_{b1}\to J/\psi J/\psi$ process and find that its branching ratio is big enough to be measured at the B-factories.