Psi' to J/Psi Ratio in Diffractive Photoproduction

TL;DR

This paper evaluates the Psi' to J/Psi ratio in diffractive photoproduction using a light-cone framework, revealing discrepancies with experimental data and suggesting a more compact charm-anticharm wave function.

Contribution

It introduces a light-cone approach with wave functions from potential models to analyze the ratio, challenging current assumptions and providing new predictions.

Findings

The estimated ratio is 2 to 5 times lower than experimental data.

The charm-anticharm wave function is more compact than potential models suggest.

The inelastic ratio exceeds the elastic ratio and matches hadroproduction measurements.

Abstract

We evaluate the Psi' to J/Psi ratio in diffractive photoproduction in a light-cone framework, using charmonium wave functions extracted from non-relativistic potential models. Contrary to current belief, we find that the best estimate for the ratio is a factor 2 to 5 below the data. The measured ratio constrains the distribution of the charm quark-antiquark component of the charmonium light-cone wave function and indicates that it is more compact than in potential models. We predict that the inelastic photoproduction ratio will be bigger than the elastic one, and will equal that measured in hadroproduction.