K +–nucleus elastic scattering revisited from the perspective of partial restoration of chiral symmetry

Kenji Aoki,Daisuke Jido

doi:10.1093/ptep/ptx133

Abstract

The $K^{+}$ meson properties in the nuclear medium are investigated by considering the wavefunction renormalization as a first step to reveal the in-medium properties of the $K^{+}$ meson in the context of partial restoration of chiral symmetry. The $K^{+}N$ elastic scattering amplitude is constructed using chiral perturbation theory up to the next-to-leading order. Using the constructed amplitude, we calculate the wavefunction renormalization in the Thomas-Fermi approximation. We obtained a good description of the $K^{+}N$ elastic scattering amplitude. The obtained wavefunction renormalization factor suggests the 2 to 6% enhancement of the $K^{+}N$ interaction at the saturation density. We conclude that the wavefunction renormalization could be one of the important medium effects for the $K^{+}$ meson.

Highlights

The strong interaction properties of hadron in the nuclear medium has attracted considerable interests, in particular, for the purpose of proving the spontaneous breaking of chiral symmetry from the experimental facts
The aim of this paper is to describe the role of the wavefunction renormalization in the in-medium K+ self-energy, that is the optical potential for K+ in the nuclear medium
We describe the K+N scattering amplitude based on chiral perturbation theory and see whether the wavefunction renormalization explains the enhancement of the K+N interaction in the nuclear medium

Summary

Introduction

The strong interaction properties of hadron in the nuclear medium has attracted considerable interests, in particular, for the purpose of proving the spontaneous breaking of chiral symmetry from the experimental facts. We do not know whether the partial restoration of chiral symmetry systematically occurs in other systems than the pion-nucleus system For this purpose, we would like to consider the NG bosons with strangeness. Once partial restoration of chiral symmetry takes places in nuclear matter by reduction of the chiral order parameters, it changes the energy scale of the vacuum and renormalizes the NG boson field. For these reasons, we would like to examine the wavefunction renormalization of the inmedium K+ using the in-vacuum K+N elastic scattering amplitude calculated from chiral perturbation theory and its unitarization.

Wavefunction renormalization

Chiral perturbation theory

Coulomb corrections

Summarry and Conclusion

Findings

Unitarization