Zusammenfassung
By using lattice QCD computations we determine the sigma terms and strangeness content of all octet baryons by means of an application of the Hellmann-Feynman theorem. In addition to polynomial and rational expressions for the quark-mass dependence of octet members, we use SU(3) covariant baryon chiral perturbation theory to perform the extrapolation to the physical up and down quark masses. Our ...
Zusammenfassung
By using lattice QCD computations we determine the sigma terms and strangeness content of all octet baryons by means of an application of the Hellmann-Feynman theorem. In addition to polynomial and rational expressions for the quark-mass dependence of octet members, we use SU(3) covariant baryon chiral perturbation theory to perform the extrapolation to the physical up and down quark masses. Our Nf = 2 + 1 lattice ensembles include pion masses down to about 190 MeV in large volumes (M pi L greater than or similar to 4), and three values of the lattice spacing. Our main results are the nucleon sigma term sigma(pi N) = 39(4)((+18)(-7)) and the strangeness content y(N) = 0.20(7)((+13)(-17)). Under the assumption of validity of covariant baryon chi PT in our range of masses one finds y(N) = 0.276(77)((+90)(-62)).
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