Baryon decays $J/\psi\rightarrow B\bar{B}$ within the QCD factorisation framework

TL;DR

This paper analyzes $J/ar{J}$ decays into baryon pairs using QCD factorization, highlighting the role of twist-4 amplitudes and achieving a reasonable match with experimental polarization data.

Contribution

It introduces a detailed calculation of decay amplitudes within collinear QCD factorization, including subleading twist-4 contributions for the first time.

Findings

Polarization parameter $\alpha_B$ can be described within 10-30% accuracy.

pQCD contributions likely dominate the polarization observable.

Qualitative agreement with experimental data achieved.

Abstract

We investigate $J/\psi$ decays into octet baryon-antibaryons pairs. The decay amplitudes are computed within the collinear QCD factorisation framework. The subleading amplitude, which describes the decay of longitudinally polarised charmonium, is computed using twist-4 three-quark distribution amplitudes. The obtained results are used for a qualitative analysis of the experimental data. It is found that the polarisation parameter $\alpha_B$ can be described with an accuracy $10-30\%$, which may indicate that the pQCD contribution dominates this observable.