{sigma}-nuclear spin-orbit coupling from two-pion exchange

Journal Article · Sat Dec 15 04:00:00 EST 2007 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.76.068201· OSTI ID:21068020

Kaiser, N ^[1]

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1. Physik-Department T39, Technische Universitaet Muenchen, D-85747 Garching (Germany)

Using SU(3) chiral perturbation theory we calculate the density-dependent complex-valued spin-orbit coupling strength U{sub {sigma}}{sub ls}(k{sub f})+iW{sub {sigma}}{sub ls}(k{sub f}) of a {sigma} hyperon in the nuclear medium. The leading long-range {sigma}N interaction arises from iterated one-pion exchange with a {lambda} or a {sigma} hyperon in the intermediate state. We find from this unique long-range dynamics a sizable ''wrong-sign'' spin-orbit coupling strength of U{sub {sigma}}{sub ls}(k{sub f0}){approx_equal}-20 MeV fm{sup 2} at normal nuclear matter density {rho}{sub 0}=0.16 fm{sup -3}. The strong {sigma}N{yields}{lambda}N conversion process contributes at the same time an imaginary part of W{sub {sigma}}{sub ls}(k{sub f0}){approx_equal}-12 MeV fm{sup 2}. When combined with estimates of the short-range contribution the total {sigma}-nuclear spin-orbit coupling becomes rather weak.

• OSTI ID: 21068020
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 6 Vol. 76; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
CHIRALITY
COMPLEXES
INTERMEDIATE STATE
L-S COUPLING
LAMBDA BARYONS
MEV RANGE
NUCLEAR MATTER
NUCLEON-HYPERON INTERACTIONS
PERTURBATION THEORY
PIONS
SIGMA BARYONS
SU-3 GROUPS