The nucleon mass and pion-nucleon sigma term from a chiral analysis of Nf = 2 lattice QCD world data

Autor: Alvarez-Ruso L., Ledwig T., Martin Camalich J., Vicente Vacas M. J.
Jazyk: angličtina
Rok vydání: 2014
Předmět:
Zdroj: EPJ Web of Conferences, Vol 66, p 06001 (2014)
Druh dokumentu: article
ISSN: 2100-014X
DOI: 10.1051/epjconf/20146606001
Popis: We investigate the pion-mass dependence of the nucleon mass within the covariant SU(2) baryon chiral perturbation theory up to order p4 with and without explicit Δ (1232) degrees of freedom. We fit lattice QCD data from several collaborations for 2 and 2+1 flavor ensembles. Here, we emphasize our Nf = 2 study where the inclusion the Δ (1232) contributions stabilizes the fits. We correct for finite volume and spacing effects, set independently the lattice QCD scale by a Sommer-scale of r0 = 0.493(23) fm and also include one σπN lQCD data point at Mπ ≈ 290 MeV. We obtain low-energy constants of natural size which are compatible with the rather linear pion-mass dependence observed in lattice QCD. We report a value of σπN = 41(5)(4) MeV for the 2 flavor case and σπN = 52(3)(8) MeV for 2+1 flavors.
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