The influence of $\delta$ meson on the isospin splitting of in-medium $NN\to N\Delta$ cross sections

Abstract

The isospin splitting of the in-medium $NN\to N\Delta$ cross sections in asymmetric nuclear medium are investigated in the framework of the one-boson exchange model by including $\delta$ and $\rho$ mesons. Our results show that the medium correction factors $R={\sigma }_{NN\to N\Delta }^{\ast }/{\sigma }_{NN\to N\Delta }^{\text{free}}$ have $R_{pp\to n{\Delta }^{++}}<R_{nn\to p{\Delta }^{-}}$ and $R_{NN\to N{\Delta }^{+}}<R_{NN\to N{\Delta }^0}$ by using the without-$\delta$ sets. By including the $\delta$ meson, it appears the totally opposite results in the $R$ for different channels, i.e., $R_{pp\to n{\Delta }^{++}}>R_{nn\to p{\Delta }^{-}}$ and $R_{NN\to N{\Delta }^{+}}>R_{NN\to N{\Delta }^0}$.

Comments: 15 pages, 4 figures