The propagation of a $\Lambda$ hyperon in nuclear matter is studied within the Green’s function formalism. The probability density for adding a $\Lambda$ hyperon with momentum $k$ to the correlated nuclear matter ground state is obtained from the complete energy dependence of the real and imaginary parts of the $\Lambda$ self-energy. This self-energy incorporates the effects of short-range correlations induced by the hyperon-nucleon interaction and the strong coupling between $\Lambda N$ and $\Sigma N$ states which is known to be crucial for a correct determination of the $\Lambda$ binding energy. The calculated spectral functions and quasi-particle parameters for the $\Lambda$ are found to be qualitatively similar to corresponding results for correlated nucleons. In general, the $\Lambda$ is less strongly correlated with the nuclear matter environment at $k_F=1.36{\mathrm{fm}}^{-1}$ than a nucleon, in agreement with empirical information from finite nuclei.

• Received 20 April 2004

DOI:https://doi.org/10.1103/PhysRevC.70.044301