Effect of energy conservation on in-medium $\mbox{NN}\to \mbox{N}Δ$ cross section in isospin-asymmetric nuclear matter

Abstract

In this paper, the in-medium $NN\to N\Delta$ cross section is calculated in the framework of the one-boson exchange model by including the isovector mesons, i.e. $\delta$ and $\rho$ mesons. Due to the isospin exchange in the $NN\to N\Delta$ process, the vector self-energies of the outgoing particles are modified relative to the incoming particles in isospin asymmetric nuclear matter, and it leads to the effective energies of the incoming $NN$ pair being different from the outgoing $N\Delta$ pair. This effect is investigated in the calculation of the in-medium $NN\to N\Delta$ cross section. With the corrected energy conservation, the cross sections of the ${\Delta }^{++}$ and ${\Delta }^{+}$ channels are suppressed, and the cross sections of the ${\Delta }^0$ and ${\Delta }^{-}$ channels are enhanced relative to the results obtained without properly considering the potential energy changes. Our results further confirm the dependence of medium correction factor, $R={\sigma }_{NN\to N\Delta }^{\ast }/{\sigma }_{NN\to N\Delta }^{\text{free}}$, on the charge state of $NN\to N\Delta$ especially around the threshold energy, but the isospin splitting of medium correction factor $R$ becomes weak at high beam energies.

arXiv comment8 pages, 5 figures, accepted by Phys.Rev.c

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Cited by in corpus (8)

• Progress of Quantum Molecular Dynamics model and its applications in Heavy Ion Collisions
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• In-medium $\mbox{NN}\to \mbox{N}Δ$ cross section and its dependence on effective Lagrange parameters in isospin-asymmetric nuclear matter
• Pion production and absorption in heavy-ion collisions
• The influence of $\delta$ meson on the isospin splitting of in-medium $NN\to N\Delta$ cross sections
• Probing in-medium nucleon-nucleon inelastic scattering cross section by using energetic n/p ratio
• Nucleon-$\Delta$ elastic cross section in isospin-asymmetric nuclear medium with inclusion of scalar-isovector $\delta$ meson field
• In-medium pion dispersion relation and medium correction of $N\pi \leftrightarrow \Delta$ near the threshold energy of pion production