High momentum protons in superdense neutron matter

Abstract

Recent observations of strong dominance of pn as compared to pp and nn short range correlations (SRCs) in nuclei indicate on possibility of unique new condition for asymmetric high density nuclear matter, in which the pp and nn interactions are suppressed while the pn interactions are enhanced due to tensor interaction. We demonstrate that, due to this enhancement, in high density neutron matter containing small portion of proton component the momentum distribution of protons is strongly deformed towards the high momentum states. This result is obtained by extracting the probabilities of two-nucleon (2N) SRCs from the analysis of the experimental data on high momentum transfer A(e,′e)X reactions and fitting them as a function of nuclear density and asymmetry. Using this fit we estimated that starting at three nuclear saturation densities the protons with fractional densities xp = 19 will populate mostly the high momentum tail of the momentum distribution while only few% of the neutrons will do so. We discuss the possible implications of this result for neutron stars.