A Deeply Bound Dibaryon is Incompatible with Neutron Stars and Supernovae

TL;DR

The study shows that a deeply bound dibaryon would destabilize neutron stars and contradict supernova observations unless its production cross section is extremely suppressed.

Contribution

It demonstrates that the existence of a deeply bound dibaryon is incompatible with neutron star stability and supernova data under typical conditions.

Findings

Dibaryons can rapidly equilibrate in neutron star conditions.

Such dibaryons would destabilize neutron stars and contradict supernova observations.

Suppression of S dibaryon production is necessary for compatibility.

Abstract

We study the effect of a dibaryon, S, in the mass range 1860 MeV < m_S < 2054 MeV, which is heavy enough not to disturb the stability of nuclei and light enough to possibly be cosmologically metastable. Such a deeply bound state can act as a baryon sink in regions of high baryon density and temperature. We find that the ambient conditions encountered inside a newly born neutron star are likely to sustain a sufficient population of hyperons to ensure that a population of S dibaryons can equilibrate in less than a few seconds. This would be catastrophic for the stability of neutron stars and the observation of neutrino emission from the proto-neutron star of Supernova 1987A over ~ O(10)s. A deeply bound dibaryon is therefore incompatible with the observed supernova explosion, unless the cross section for S production is severely suppressed.