Lorentz contraction, geometry and range in antiproton-proton annihilation into two pions

Abstract

We present a geometric interpretation of the so-called annihilation range in reactions of the type $\bar{p}p\to$ {\em two light mesons} based upon Lorentz effects in the highly relativistic final states ($\gamma =E_{\mathrm{cm}}/2m{c}^2\simeq 6.8-8.0$). Lorentz-boosted meson wave functions, within the framework of the constituent quark model, result in a richer angular dependence of the annihilation amplitudes and thus in higher partial wave contributions ($J>1$) than usually obtained. This approach sheds some light on what could be a "{\em short}" annihilation range and how it is influenced by the angular distribution of the final states.

Comments: LEAP05 (Bonn/Juelich) proceedings, 5 pages