Chiral expansion of Baryon masses and {sigma}-terms

Journal Article · Sat Feb 01 04:00:00 EST 1997 · Annals of Physics (New York)

DOI:https://doi.org/10.1006/aphy.1996.5630· OSTI ID:544336

Borasoy, B ^[1]; Meissner, U ^[1]

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1. Universituet Bonn, Institut fuer Theoretische Kernphysik, Nussallee 14-16, D-53115 Bonn (Germany)

We analyze the octet baryon masses and the pion/kaon-nucleon {sigma}-terms in the framework of heavy baryon chiral perturbation theory. We include {ital all} terms up-to-and-including quadratic order in the light quark masses, m{sub q}. We develop a consistent scheme to estimate low-energy constants related to scalar-isoscalar operators in the framework of resonance exchange involving one-loop graphs. The pertinent low-energy constants can only be estimated up to some finite coefficients. Including contributions from loop graphs with intermediate spin-3/2 decuplet and spin-1/2 octet states and from tree graphs including scalar mesons, we use the octet baryon masses and the pion-nucleon {sigma}-term to fix all but one of these coefficients. Physical results are insensitive to this remaining parameter. It is also demonstrated that two-loop corrections only modify some of the subleading low-energy constants. We find for the baryon mass in the chiral limit, m=770{plus_minus}110MeV. While the corrections of order m{sub q}{sup 2} are small for the nucleon, they are still sizeable for the {Lambda}, the {Sigma} and the {Xi}. Therefore a definitive statement about the convergence of three-flavor baryon chiral perturbation cannot yet be made. The strangeness content of the nucleon is y=0.21{plus_minus}0.20. We also estimate the kaon-nucleon {sigma}-terms and some two-loops contributions to the nucleon mass. {copyright} 1997 Academic Press, Inc.

• OSTI ID: 544336
• Journal Information: Annals of Physics (New York), Journal Name: Annals of Physics (New York) Journal Issue: 1 Vol. 254; ISSN APNYA6; ISSN 0003-4916
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BARYONS
CHIRAL SYMMETRY
GOLDSTONE BOSONS
KAON-NUCLEON INTERACTIONS
MASS
MESON-BARYON INTERACTIONS
OCTET MODEL
PARTICLE MULTIPLETS
PERTURBATION THEORY
PION-NUCLEON INTERACTIONS
QUARK MODEL
RENORMALIZATION