Effects of Relativistic Dynamics in $pp\to pp{\pi }^0$ near Threshold

Abstract

The cross-section for threshold ${\pi }^0$ production in proton-proton collisions is evaluated in the framework of the covariant spectator description. The negative energy intermediate states are included non-perturbatively and seen to yield a considerably smaller contribution, when compared to perturbative treatments. A family of OBE-models with different off-shell scalar coupling is considered.

Comments: 10 pages, 3 figures, 1 table