Three-body force effect on off-shell mass operator and spectral functions in nuclear matter

TL;DR

This paper investigates how three-body forces influence the off-shell behavior of the nucleon mass operator and spectral functions in nuclear matter within the Brueckner theory, revealing density-dependent effects.

Contribution

It introduces the inclusion of nuclear three-body forces into the off-shell analysis of the mass operator and spectral functions in nuclear matter.

Findings

TBF effects are negligible at saturation density.

At twice saturation density, TBF significantly affects spectral functions.

TBF may enhance depletion of hole states at high density.

Abstract

Within the framework of the Brueckner theory, the off-shell behaviors of the mass operator $M(k,\omega)=V(k,\omega)+iW(k,\omega)$, i.e., its dependence upon the momentum $k$ and upon the nucleon frequency $\omega$, are investigated by including nuclear three-body force (TBF). The first two terms of the hole-line expansion of the mass operator are taken into account. The TBF effects on their off-shell properties are discussed. A comparison is made between the on-shell and off-shell values of $M_{1}$. The nucleon spectral function and nucleon momentum distribution are also calculated, and the calculation shows that they are hardly affected by the TBF effect at the saturation density. At a high density two times greater than the saturation density, inclusion of the TBF may lead to a visible effect on the spectral function and may enhance the depletion of the hole states.