Half off-shellT-matrix studies with pp-Bremsstrahlung

Abstract

Two nucleon t-matrices, on-and half off-shell, of experiment and theory are used to put expectations into new Bremsstrahlung experiments on a realistic basis. A report is given about comprehensive studies of pp Bremsstrahlung which includes a reanalysis of TRIUMF data and other data of non coplanar geometry experiments. The Bremsstrahlung amplitudes associated with external, rescattering and exchange currents, by exact treatment of the Coulomb potential in on-and half-off-shell t-matrices, and the relativistic spin corrections were all computed and for both coplanar and non coplanar geometries.

Pauli principle in the soft-photon approach to proton-proton bremsstrahlung

“…) is a suitable amplitude to use in describing the ppγ process, because it meets all theoretical requirements. As we have noted above, even though the amplitude M T uT ts 2µ does not satisfy the Pauli principle at the order K, its numerical predictions are close to the results calculated from the amplitude M T uT ts µ , potential models [7][8][9][10][11], and the OBE model [12], for most cases. That is, the violation of the Pauli principle is not serious, and the amplitude describes the ppγ cross sections rather well.…”

The Δ-isobar and proton-proton bremsstrahlung

“…The nucleon-nucleon bremsstrahlung (NN~,) reaction as a tool for investigating the off-shell behaviour of the nucleon-nucleon (NN) interaction has recently regained increasing attention both experimentally and theoretically [1][2][3][4][5][6][7][8]. With the development of modern facilities to perform the necessary detailed experiments combined with more sophisticated theoretical models than were available in the past, we are now in a much better position to investigate off-shell effects.…”

“…Most of the modern NN interactions, although they may be based on quite different NN potential models, differ only slightly in their predictions for observables in the bremsstrahlung reaction [4][5][6][7][8]. They are, however, based on purely phenomenological and/or meson exchange descriptions that include either nucleon or nucleon and meson degrees of freedom only.…”

“…Moreover, the present status of the bremsstrahlung theory, within the framework of nucleon and meson degrees of freedom, leaves relatively little room for higher order corrections. Apart from the two-body current contribution beyond the Soft-Photon Approximation (SPA), most of the higher order corrections which are believed to be most important have been considered in recent calculations [4][5][6][7].…”

Novel soft-photon analysis of ppγ below pion-production threshold

“…The amplitude M T sT ts µ (s i , s f ; t q , t p ) can be formally obtained from the amplitude M T uT ts µ (u 1 , u 2 ; t q , t p ) given by Eqs. (2), (3), and (4) by making the following substitutions: [13] and a Paris-potential calculation [14].…”