Measurement of Light-Cone Wave Functions by Diffractive Dissociation

TL;DR

This paper presents experimental measurements of the pion's light-cone wave function through diffractive dissociation, confirming the asymptotic form at high Q^2 and providing evidence for color transparency, with implications for photon wave functions.

Contribution

First experimental verification of the pion's light-cone wave function via diffractive di-jet production at Fermilab, supporting the asymptotic QCD model and observing color transparency effects.

Findings

The $|q\bar{q}>$ wave function fits data well at high Q^2.

Evidence for color transparency from A-dependence measurements.

Proposes similar studies for photon wave functions.

Abstract

Diffractive dissociation of particles can be used to study their light-cone wave function. Results from Fermilab experiment E791 for diffractive dissociation of 500 GeV/c $\pi^-$ mesons into di-jets are presented. The results show that the $|q\bar {q}>$ light-cone asymptotic wave function describes the data well for $Q^2 \sim 10 ~{\rm (GeV/c)^2}$ or more. Evidence for color transparency comes from a measurement of the $A$-dependence of the yield of the diffractive di-jets. It is proposed to carry out similar studies for the light-cone wave function of the photon.