Quantitative measure of the isospin splitting of the effective nucleon mass

The effective nucleon mass splits into two components, one for the proton and another for the neutron, in the case of adding the isovector coupling channel of the nuclear interaction, while being the same in the case of considering only the isoscalar coupling. A quantitative measure of the splitting is defined by the root mean square (RMS) value of the effective nucleon mass splitting and applied to the effective nucleon mass splitting in lead and tin isotopes. The isospin splitting of the effective nucleon mass is found to increase almost linearly with the asymmetry parameter.

The influence of δ meson on the isospin splitting of in-medium NN → NΔ cross-sections

The isospin splitting of the in-medium [Formula: see text] cross-sections in asymmetric nuclear medium is investigated in the framework of the one-boson exchange model by including [Formula: see text] and [Formula: see text] mesons. Our results show that the medium correction factors [Formula: see text] have [Formula: see text] and [Formula: see text] by using the without-[Formula: see text] sets. By including the [Formula: see text] meson, there appear the totally opposite results in the [Formula: see text] for different channels, i.e., [Formula: see text] and [Formula: see text].

A tmQCD mixed-action approach to flavour physics

We discuss a mixed-action approach in which sea quarks are regularised using non-perturbatively O(a) improved Wilson fermions, while a fully-twisted tmQCD action is used for valence quarks. In this setup, automatic O(a) improvement is preserved for valence observables, apart from small residual O(a) effects from the sea. A strategy for matching sea and valence is set up, and carried out for Nf = 2 + 1 CLS ensembles with open boundary conditions at several simulation points. The scaling of basic light-quark observables such as the pseudoscalar meson decay constant is studied, as well as the isospin splitting of pseudoscalar meson masses.

Holographic estimate of isospin splitting in hadron mass

We present the calculations of isospin splitting mass of pions and nucleons in the Sakai–Sugimoto model of holographic QCD. We find that [Formula: see text] and the electromagnetic mass difference of nucleons, [Formula: see text], taking the Kaluza–Klein scale, [Formula: see text].