Variational calculation of the ppK^- system based on chiral SU(3) dynamics

TL;DR

This study uses a variational approach with chiral SU(3) dynamics to investigate the ppK^- system, concluding it is not deeply bound and providing estimates for its binding energy and decay width.

Contribution

It introduces a variational method combined with chiral SU(3) derived interactions to analyze the ppK^- system, accounting for theoretical uncertainties and additional effects.

Findings

ppK^- is not deeply bound, with a binding energy around 20 MeV.

Decay width involving KbarN -> πY ranges from 40 to 70 MeV.

Including additional effects, the width can reach up to 100 MeV.

Abstract

The ppK^- system, as a prototype for possible quasibound Kbar nuclei,is investigated using a variational approach. Several versions of energy dependent effective KbarN interactions derived from chiral SU(3) dynamics are employed as input, together with a realistic NN potential (Av18). Taking into account theoretical uncertainties in the extrapolations below the KbarN threshold, we find that the antikaonic dibaryon ppK^- is NOT deeply bound. With the driving s-wave KbarN interaction the resulting total binding energy is B(ppK^-) = 20 $\pm$ 3 MeV and the mesonic decay width involving KbarN -> \pi Y is expected to be in the range 40 - 70 MeV. Properties of this quasibound ppK^- system (such as density distributions of nucleons and antikaon) are discussed. The \Lambda(1405), as an I=0 quasi-bound state of Kbar and a nucleon, appears to survive in the ppK^- cluster. Estimates are given for the influence of p-wave KbarN interactions and for the width from two-nucleon absorption (KbarNN -> YN) processes. With inclusionof these effects and dispersive corrections from absorption, the ppK^- binding energy is expected to be in the range 20 - 40 MeV, while the total decay width can reach 100 MeV but with large theoretical uncertainties.