Antikaon absorption in the nuclear medium: the role of hadron self-energies and implications for kaonic atoms

TL;DR

This study develops a comprehensive microscopic model of $K^-$-nuclear interactions incorporating in-medium effects, hadron self-energies, and absorption processes, successfully explaining kaonic atom data and absorption channels.

Contribution

It introduces a detailed in-medium $K^-$-nuclear potential model with hadron self-energies and absorption processes, achieving the best fit to experimental kaonic atom data to date.

Findings

Lowest $ ilde{ ext{chi}}^2/d.p$ value of 1.5 among models

Good agreement with experimental energy shifts and widths

Accurate branching ratios for absorption channels

Abstract

A systematic study of all relevant in-medium effects on the total $K^-$-nuclear potential is presented in this work. The $K^-N$ scattering amplitudes, including Pauli blocking effects and hadron self-energies (hyperons, nucleons, pions and kaons), are derived within a next-to-leading order chiral meson-baryon coupled-channel interaction model. These amplitudes are employed in a microscopic model of the $K^-$-nuclear potential in symmetric nuclear matter that includes one-, two- and, when the kaons and pions are dressed, also multinucleon absorption processes. The potential is then applied in calculations of the strong energy shifts and widths of 64 measured kaonic atom levels. The comparison of the results of the full model that includes Pauli correlations and hadron self-energies with data provides $\chi^2 /d.p=1.5$, the lowest value obtained by a theoretical model to date and comparable with that of the best fitted phenomenological potentials. Furthermore, the calculated branching ratios for mesonic and non-mesonic absorption channels in kaonic carbon and kaonic neon are in good agreement with available data.