Many-body exchange currents and the tri- and four-nucleon charge form factors

Abstract

We find that the three-body two-pion-exchange currents lead to an effect very similar to that of the two-body one-pion-exchange currents on the charge form factors of $^{3}\mathrm{H}$, $^{3}\mathrm{He}$, and $^{4}\mathrm{He}$. Most of this effect is, however, canceled by similar $\ensuremath{\rho}$-meson-exchange currents. The four-body three-meson-exchange currents are of negligible importance for the \ensuremath{\alpha}-particle charge form factor.NUCLEAR REACTIONS $^{3}\mathrm{He}$, $^{3}\mathrm{H}$, $^{4}\mathrm{He}(e,e)$; calculated charge form factors with 2-, 3-, and 4-body meson-exchange operators; pion exchange with/without $\ensuremath{\rho}$ exchange; simple wave functions; effects of correlations, vertex factors.