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arXiv · 1511.05859

Strangeness S=-2 baryon-baryon interaction at next-to-leading order in chiral effective field theory

J. Haidenbauer·Ulf-G. Meißner·S. Petschauer
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Abstract

The strangeness $S=-2$ baryon-baryon interaction is studied in chiral effective field theory up to next-to-leading order. The potential at this order consists of contributions from one- and two-pseudoscalar-meson exchange diagrams and from four-baryon contact terms without and with two derivatives. SU(3) flavor symmetry is imposed for constructing the interaction in the $S=-2$ sector. Specifically, the couplings of the pseudoscalar mesons to the baryons are fixed by SU(3) symmetry and, in general, also the contact terms are related via SU(3) symmetry to those determined in a previous study of the $S=-1$ hyperon-nucleon interaction. The explicit SU(3) symmetry breaking due to the physical masses of the pseudoscalar mesons ($π$, $K$, $η$) is taken into account. It is argued that the $ΞN$ interaction has to be relatively weak to be in accordance with available experimental constraints. In particular, the published values and upper bounds for the $Ξ^- p$ elastic and inelastic cross sections apparently rule out a somewhat stronger attractive $ΞN$ force and, specifically, disfavor any near-threshold deuteron-like bound states in that system.

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J. Haidenbauer, Ulf-G. Meißner, S. Petschauer. 2015-11-18. Strangeness S=-2 baryon-baryon interaction at next-to-leading order in chiral effective field theory. https://doi.org/10.1016/j.nuclphysa.2016.01.006

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