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Title: Chiral dynamics of {sigma} hyperons in the nuclear medium

Abstract

Using SU(3) chiral perturbation theory, we calculate the density-dependent complex mean field U{sub {sigma}}(k{sub f})+i W{sub {sigma}}(k{sub f}) of a {sigma} hyperon in isospin-symmetric nuclear matter. The leading long-range {sigma}N interaction arises from one-kaon exchange and from two-pion exchange with a {sigma} or a {lambda} hyperon in the intermediate state. We find from the {sigma}N{yields}{lambda}N conversion process at nuclear matter saturation density {rho}{sub 0}=0.16 fm{sup -3} an imaginary single-particle potential of W{sub {sigma}}(k{sub f0})=-21.5 MeV, in fair agreement with existing empirical determinations. The genuine long-range contributions from iterated (second order) one-pion exchange with an intermediate {sigma} or {lambda} hyperon sum to a moderately repulsive real single-particle potential of U{sub {sigma}}(k{sub f0})=59 MeV. Recently measured ({pi}{sup -},K{sup +}) inclusive spectra related to {sigma}{sup -} formation in heavy nuclei give evidence for a {sigma}-nucleus repulsion of similar size. Our results suggest that the net effect of the short-range {sigma}N interaction on the {sigma} nuclear mean field could be small.

Authors:
 [1]
  1. Physik-Department T39, Technische Universitaet Muenchen, D-85747 Garching (Germany)
Publication Date:
OSTI Identifier:
20698793
Resource Type:
Journal Article
Journal Name:
Physical Review. C, Nuclear Physics
Additional Journal Information:
Journal Volume: 71; Journal Issue: 6; Other Information: DOI: 10.1103/PhysRevC.71.068201; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0556-2813
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; CHIRAL SYMMETRY; CHIRALITY; HEAVY NUCLEI; HYPERNUCLEI; INTERMEDIATE STATE; ISOSPIN; KAONS PLUS; MEAN-FIELD THEORY; MEV RANGE; NUCLEAR MATTER; NUCLEAR POTENTIAL; NUCLEON-HYPERON INTERACTIONS; PERTURBATION THEORY; PION-NUCLEON INTERACTIONS; PIONS MINUS; QUANTUM FIELD THEORY; SIGMA MINUS PARTICLES; SU-3 GROUPS

Citation Formats

Kaiser, N. Chiral dynamics of {sigma} hyperons in the nuclear medium. United States: N. p., 2005. Web. doi:10.1103/PhysRevC.71.068201.
Kaiser, N. Chiral dynamics of {sigma} hyperons in the nuclear medium. United States. https://doi.org/10.1103/PhysRevC.71.068201
Kaiser, N. Wed . "Chiral dynamics of {sigma} hyperons in the nuclear medium". United States. https://doi.org/10.1103/PhysRevC.71.068201.
@article{osti_20698793,
title = {Chiral dynamics of {sigma} hyperons in the nuclear medium},
author = {Kaiser, N},
abstractNote = {Using SU(3) chiral perturbation theory, we calculate the density-dependent complex mean field U{sub {sigma}}(k{sub f})+i W{sub {sigma}}(k{sub f}) of a {sigma} hyperon in isospin-symmetric nuclear matter. The leading long-range {sigma}N interaction arises from one-kaon exchange and from two-pion exchange with a {sigma} or a {lambda} hyperon in the intermediate state. We find from the {sigma}N{yields}{lambda}N conversion process at nuclear matter saturation density {rho}{sub 0}=0.16 fm{sup -3} an imaginary single-particle potential of W{sub {sigma}}(k{sub f0})=-21.5 MeV, in fair agreement with existing empirical determinations. The genuine long-range contributions from iterated (second order) one-pion exchange with an intermediate {sigma} or {lambda} hyperon sum to a moderately repulsive real single-particle potential of U{sub {sigma}}(k{sub f0})=59 MeV. Recently measured ({pi}{sup -},K{sup +}) inclusive spectra related to {sigma}{sup -} formation in heavy nuclei give evidence for a {sigma}-nucleus repulsion of similar size. Our results suggest that the net effect of the short-range {sigma}N interaction on the {sigma} nuclear mean field could be small.},
doi = {10.1103/PhysRevC.71.068201},
url = {https://www.osti.gov/biblio/20698793}, journal = {Physical Review. C, Nuclear Physics},
issn = {0556-2813},
number = 6,
volume = 71,
place = {United States},
year = {2005},
month = {6}
}