A Consistent Meson-Field-Theoretical Description of PP-Bremsstrahlung
Abstract
Description
A parameter-free and relativistic extension of the RuhrPot meson-baryon model is used to define the dominant isoscalar meson-exchange currents. We compute pp-bremsstrahlung observables below the $π-$production threshold using a relativistic hadronic current density that includes impulse, wave function re-orthonormalization, meson-recoil, $\bar{\rm N}$N creation and annihilation, $ρπγ$ + $ωπγ$ + $ρηγ$ + $ωηγ$ vector-meson decay and N$Δγ(π,ρ)$ exchange currents. We obtain a good description of the available data. The N$Δγ(π)$ current is shown to dominate the large two-body contributions and closed-form expressions for various non-relativistic approximations are analyzed. An experimental sensitivity to the admixture of pseudo-scalar and pseudo-vector admixture of the NN$π$ interaction is demonstrated. We examine the Lorentz invariance of the NN$\rightleftharpoons$NN $t$-matrices and show a dominantly pseudo-vector NN$π$ coupling renders impulse approximation calculations without boost operators to be essentially exact. Conversely, a similar analysis of the $Δ{\rm N}\rightleftharpoons$NN transitions shows that boost operators and the two-body $NΔγ$ wave function re-orthonormalization meson-recoil currents are required in NN, $Δ$N and $ΔΔ$ coupled channel $t$-matrix applications. The need for additional data is stressed.
34 pages of uuencoded REVTeX using multicol.sty with 21 figures inlined using epsf.sty. This revision adds section IV.H
34 pages of uuencoded REVTeX using multicol.sty with 21 figures inlined using epsf.sty. This revision adds section IV.H