92 research outputs found
The baryon-decuplet in the chiral dynamics of Lambda-hyperons in nuclear matter
We study the long range part of the -hyperon optical potential in
nuclei using Quantum Many Body techniques and flavor-SU(3) Chiral Lagrangians
as starting point. More precisely, we study the contributions to the
-hyperon optical potential due to the long-range two-pion exchange,
with and baryons in the internal baryonic lines and
considering Nh and h excitations. We also consider the contribution to
the spin-orbit potentials that comes out from these terms. Our results support
a natural explanation of the smallness of the -nuclear spin-orbit
interaction and shows the importance of the and degrees of
freedom for the hyperon-nucleus interactions.Comment: 8 pages, 5 figure
Electromagnetic properties of baryons
We discuss the chiral behavior of nucleon and Delta(1232) electromagnetic
properties within the framework of a SU(2) covariant baryon chiral perturbation
theory. Our one-loop calculation is complete to the order p^3 and p^4/Delta
with Delta as the Delta(1232)-nucleon energy gap. We show that the magnetic
moment of a resonance can be defined through the linear energy shift only when
an additional relation between the involved masses and the applied magnetic
field strength is fulfilled. Singularities and cusps in the pion mass
dependence of the Delta(1232) electromagnetic moments reflect a
non-fulfillment. We show results for the pion mass dependence of the nucleon
iso-vector electromagnetic quantities and present results for finite volume
effects on the iso-vector anomalous magnetic moment.Comment: 4 pages, 3 figures, prepared for Proceedings of the International
Conference on the Structure of Baryons (BARYONS'10), Osaka, Japan, Dec. 7-11,
201
Properties of the ground-state baryons in chiral perturbation theory
We review recent progress in the understanding of low-energy baryon structure
by means of chiral perturbation theory. In particular, we discuss the
application of this formalism to the description of various properties such as
the baryon-octet magnetic moments, the electromagnetic structure of decuplet
resonances and the hyperon vector coupling . Moreover, we present the
results on the chiral extrapolation of recent lattice QCD results on the
lowest-lying baryon masses and we predict the corresponding baryonic
sigma-terms.Comment: 6 pages; shortened version to appear in the proceedings of QCD1
The lowest-lying baryon masses in covariant SU(3)-flavor chiral perturbation theory
We present an analysis of the baryon-octet and -decuplet masses using
covariant SU(3)-flavor chiral perturbation theory up to next-to-leading order.
Besides the description of the physical masses we address the problem of the
lattice QCD extrapolation. Using the PACS-CS collaboration data we show that a
good description of the lattice points can be achieved at next-to-leading order
with the covariant loop amplitudes and phenomenologically determined values for
the meson-baryon couplings. Moreover, the extrapolation to the physical point
up to this order is found to be better than the linear one given at
leading-order by the Gell-Mann-Okubo approach. The importance that a reliable
combination of lattice QCD and chiral perturbation theory may have for hadron
phenomenology is emphasized with the prediction of the pion-baryon and
strange-baryon sigma terms.Comment: Typos in formulas correcte
- …