$\Sigma$-nuclear spin-orbit coupling from two-pion exchange

Abstract

Using SU(3) chiral perturbation theory we calculate the density-dependent complex-valued spin-orbit coupling strength $U_{\Sigma ls}(k_f)+i{W}_{\Sigma ls}(k_f)$ of a $\Sigma$ hyperon in the nuclear medium. The leading long-range $\Sigma N$ interaction arises from iterated one-pion exchange with a $\Lambda$ or a $\Sigma$ hyperon in the intermediate state. We find from this unique long-range dynamics a sizeable ``wrong-sign'' spin-orbit coupling strength of $U_{\Sigma ls}(k_{f0})\simeq -20$ MeVfm${}^2$ at normal nuclear matter density ${\rho }_0=0.16$fm${}^{-3}$. The strong $\Sigma N\to \Lambda N$ conversion process contributes at the same time an imaginary part of $W_{\Sigma ls}(k_{f0})\simeq -12$ MeVfm${}^2$. When combined with estimates of the short-range contribution the total $\Sigma$-nuclear spin-orbit coupling becomes rather weak.

7 pages, 2 figures, submitted to Phys. Rev. C

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Cited by in corpus (6)

• $\bar{\mathrm{D}}$ and $\mathrm{B}$ mesons in nuclear medium
• A study of hyperons in nuclear matter based on chiral effective field theory
• Probing gluon dynamics by charm and bottom mesons in nuclear medium from heavy meson effective theory with 1/M-corrections
• Note on spin-orbit interactions in nuclei and hypernuclei
• Bound states of spin-orbit coupled cold atoms in a Dirac delta-function potential
• Discrimination of $\Sigma$-nucleus potentials in the angular distribution of elastic scattering of ${\Sigma }^{-}$ hyperons from nuclei