Aspects of strange matter

Journal Article · Thu Jul 20 04:00:00 EDT 1995 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.48708· OSTI ID:239343

Dover, C B ^[1]

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1. Department of Physics, Brookhaven National Laboratory, Upton, New York 11973 (United States)

We discuss the stability of multiply strange baryonic systems, in the context of a mean field approach obtained from an underlying set of phenomenological meson--baryon interactions. The coupling parameters which determine the conventional {sigma}+{omega} mean fields (Hartree potentials) seen by various baryon species ({ital N}, {Lambda}, {Xi}) in the many-body system are constrained by reproducing the trend of observed binding energies of single particle ({ital N}, {Lambda}, {Xi}) states, as well as the energy per particle and density of non-strange nuclear matter. We also consider additional scalar ({sigma}*) and vector ({phi}) fields which couple strongly to strange baryons. The couplings of these fields are adjusted to produce strong hyperon-hyperon interactions, as suggested by the data on {Lambda}{Lambda} hypernuclei. Extrapolating this approach to systems of large strangeness {ital S}, we find a broad class of objects composed of neutrons, protons, {Lambda}`s and {Xi}`s, which are stable against strong decay. In these systems, the presence of filled {Lambda} orbitals blocks the strong decay {Xi}{ital N} {r_arrow} {Lambda}{Lambda}, leading to a strangeness fraction {ital f}{sub {ital s}}={vert_bar} {ital S} {vert_bar}/{ital A}{approx}1, density {rho}{approx}(2{minus}3){rho}{sub 0}, and charge fraction {ital f}{sub {ital q}} in the range {minus}0.1{lt}{ital q}/{ital A}{lt}0.1, comparable to that of hypothetical stable strange quark matter (``strangelets``), but with a low binding energy per particle {ital E}{sub {ital B}}/{ital A}{approx}{minus}10 to {minus}20 MeV. Such weakly bound multi-strange objects can be stable for very large {ital A}, unlike ordinary nuclei, since the Coulomb repulsion generated by the protons is largely cancelled by the presence of a comparable number of {Xi}`s, leading to a small net charge (positive or negative) of order {ital A}{sup 1/3}. {copyright} 1995 {ital American} {ital Institute} {ital of} {ital Physics}.

• Research Organization: Brookhaven National Laboratory
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 239343
• Report Number(s): CONF-950172--
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 340; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BARYONS
DEEP INELASTIC HEAVY ION REACTIONS
NUCLEAR MATTER
PARTICLE PRODUCTION
SIGMA MODEL
STABILITY
STRANGENESS