Aspects of strange matter
- 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 Lab. (BNL), Upton, NY (United States)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 239343
- Report Number(s):
- CONF-950172-; ISSN 0094-243X; TRN: 96:012952
- Journal Information:
- AIP Conference Proceedings, Vol. 340, Issue 1; Conference: Strangeness in hadronic matter conference, Tucson, AZ (United States), 3-7 Jan 1995; Other Information: PBD: 20 Jul 1995
- Country of Publication:
- United States
- Language:
- English
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