Separation of current and spin contributions to isovector $M1\mathrm{}$ excitations by means of the ($e$,$e^{\prime }$) and ($p$,$n$) reactions

The orbital current and spin contributions to isovector $M1\mathrm{}$ excitations in light nuclei are studied microscopically by combining information from inelastic electron scattering at small momentum transfers with that obtained from recent measurements of ($p$,$n$) cross sections at forward angles. The ($p$,$n$) reaction is studied within the distorted-wave approximation using a $G$-matrix interaction and shell model wave functions and the ($e$,$e^{\prime }$) scattering is calculated in a plane wave approximation.