37 research outputs found
Pion Exchange Interaction in Bonn Potential and Relativistic and Non-relativistic Framework in Nuclear Matter
As the residual interaction of quantum chromodynamics in low-energy region,
the nucleon-nucleon (NN) potential can only be exactly described by the model
picture now. In the Bonn potential, one of the most well-known NN interaction
models, the nucleons interact with each other through exchanging the pion and
several heavier mesons, where the pion plays an essential role. It provides a
partial contribution of tensor force in the intermediate-range region and the
main component in the long-range region in NN potential. However, it is very
difficult to be treated in the nuclear many-body system due to its pseudovector
or pseudoscalar property. Recently, three high-precision charge-dependent Bonn
potentials were proposed with pseudovector coupling types and different
pion-nucleon coupling strengths and applied them to study the properties of
nuclear matter and neutron stars in the non-relativistic and relativistic
frameworks. Furthermore, to properly deal with the strong short-range repulsion
and tensor force of the NN potential, some new relativistic {\it ab initio}
methods have also been developed in the past decade to discuss the role of pion
and relativistic effects in nuclear matter.Comment: 29 pages, 12 figures, 6 tables. Contribution to the "Handbook of
Nuclear Physics", Springer Nature, 2022, Eds. I. Tanihata, H. Toki and T.
Kajin
Nuclear matter properties with nucleon-nucleon forces up to fifth order in the chiral expansion
The properties of nuclear matter are studied using state-of-the-art
nucleon-nucleon forces up to fifth order in chiral effective field theory. The
equations of state of symmetric nuclear matter and pure neutron matter are
calculated in the framework of the Brueckner-Hartree-Fock theory. We discuss in
detail the convergence pattern of the chiral expansion and the regulator
dependence of the calculated equations of state and provide an estimation of
the truncation uncertainty. For all employed values of the regulator, the
fifth-order chiral two-nucleon potential is found to generate nuclear
saturation properties similar to the available phenomenological high precision
potentials. We also extract the symmetry energy of nuclear matter, which is
shown to be quite robust with respect to the chiral order and the value of the
regulator.Comment: 10 pages, 3 figures, 3 table