Chiral SU(3) dynamics and {lambda} hyperons in the nuclear medium{sup 1}

Journal Article · Sat Jan 01 04:00:00 EST 2005 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PhysRevC.71.015203· OSTI ID:20695902

Kaiser, N; Weise, W ^[1]

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1. Physik-Department, Technische Universitaet Muenchen, D-85747 Garching (Germany)

We present a novel approach to the density-dependent mean field and the spin-orbit interaction of a {lambda} hyperon in a nuclear many-body system, based on flavor-SU(3) in-medium chiral perturbation theory. The leading long-range {lambda}N interaction arises from kaon exchange and from two-pion exchange with a {sigma} hyperon in the intermediate state. The empirical {lambda}-nucleus potential depth of about -28 MeV is well reproduced with a single cutoff scale, {lambda}=0.7 GeV, effectively representing all short-distance (high-momentum) dynamics not resolved at scales characteristic of the nuclear Fermi momentum. This value of {lambda} is remarkably consistent with the one required to reproduce the empirical saturation point of isospin-symmetric nuclear matter in the same framework. The smallness of the {lambda}-nuclear spin-orbit interaction finds a natural (yet novel) explanation in terms of an almost complete cancellation between short-range contributions (properly rescaled from the known nucleonic spin-orbit coupling strength) and long-range terms generated by iterated one pion exchange with intermediate {sigma} hyperons. The small {sigma}{lambda}-mass difference figures prominently in this context.

• OSTI ID: 20695902
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 1 Vol. 71; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
CHIRALITY
GEV RANGE
INTERMEDIATE STATE
ISOSPIN
KAONS
L-S COUPLING
LAMBDA BARYONS
MANY-BODY PROBLEM
MASS DIFFERENCE
MEAN-FIELD THEORY
MEV RANGE
NUCLEAR MATTER
NUCLEAR POTENTIAL
PERTURBATION THEORY
PIONS
SIGMA BARYONS
SU-3 GROUPS