Effective Masses and Sizes of N(939), $Δ\!\!\mbox{\boldmath(1232)}$ and N(1440) in Nuclear Medium

Hiroko Ichie, Arata Hatashigaki, Akira Suzuki, Masahiro Kimura

Published 1993-08-20Version 1

The effective masses and sizes of N(939), $\Delta(1232)$ and N(1440) in nuclear medium are calculated for a model in which quarks are subjected to a confinement force quenched by the scalar part of nuclear interactions. At the nuclear matter density, the nucleon swells by 50\% relative to the free nucleon. The masses of $\Delta(1232)$ and N(1440) decrease in nuclear medium more than the nucleon, so that the pion requires less energy to excite them in nuclear medium than it does for a free nucleon.