498 research outputs found
Scalar strangeness content of the nucleon and baryon sigma terms
The scalar strangeness content of the nucleon, characterized by the so-called
strangeness-nucleon sigma term, is of fundamental importance in understanding
its sea-quark flavor structure. We report a determination of the octet baryon
sigma terms via the Feynman-Hellmann theorem by analyzing the latest
high-statistics lattice QCD simulations with covariant baryon chiral
perturbation theory up to next-to-next-to-next-to-leading order. In particular,
we predict MeV and MeV, while
the first error is statistical and the second systematic due to different
lattice scales. The predicted is consistent with the latest LQCD
results and the results based on the next-to-next-to-leading order chiral
perturbation theory. Several key factors in determining the sigma terms are
systematically taken into account and clarified for the first time, including
the effects of lattice scale setting, systematic uncertainties originating from
chiral expansion truncations, and constraint of strong-interaction isospin
breaking effects.Comment: 6 pages, 2 figures; version to appear in Physical Review
Octet baryon masses and sigma terms in covariant baryon chiral perturbation theory
We report an analysis of the octet baryon masses using the covariant baryon
chiral perturbation theory up to next-to-next-to-next-to-leading order with and
without the virtual decuplet contributions. Particular attention is paid to the
finite-volume corrections and the finite lattice spacing effects on the baryon
masses. A reasonable description of all the publicly available
lattice QCD data is achieved.Utilyzing the Feynman-Hellmann theorem, we
determine the nucleon sigma terms as MeV and
MeV.Comment: 4 pages; presented by Xiu-Lei Ren at The Seventh International
Symposium on Chiral Symmetry in Hadrons and Nuclei (Chiral 2013), October
27-30, 2013, Beijing, Chin
- …