TY  - JOUR
AU  - Alvarez-Ruso, L.
AU  - Ledwig, T.
AU  - Martin Camalich, J.
AU  - Vicente Vacas, M. J.
PY  - 2013
DA  - 2013//
TI  - Nucleon mass and pion-nucleon sigma term from a chiral analysis of lattice QCD data
T2  - Phys. Rev. D
JO  - Physical Review D
SP  - 054507
EP  - 20pp
VL  - 88
IS  - 5
PB  - Amer Physical Soc
AB  - The pion mass dependence of the nucleon mass within the covariant SU(2) baryon chiral perturbation theory both without and with explicit Delta(1232) degrees of freedom up to order p(4) is investigated. By fitting to a comprehensive set of lattice QCD data in 2 and 2 + 1 flavors from several collaborations, for pion masses M-pi < 420 MeV, we obtain low energy constants of natural size that are compatible with pion-nucleon scattering data. Our results are consistent with the rather linear pion mass dependence showed by lattice QCD. In the 2 flavor case we have also performed simultaneous fits to nucleon mass and sigma(pi N) data. As a result of our analysis, which encompasses the study of finite volume corrections and discretization effects, we report a value of sigma(pi N) = 41(5)(4) MeV in the 2 flavor case and sigma(pi N) = 52(3)(8) MeV for 2 + 1 flavors, where the inclusion of the Delta(1232) resonance changes the results by around 9 MeV. In the 2 flavor case we are able to set independently the scale for lattice QCD data, given by a Sommer scale of r(0) = 0.493(23) fm.
SN  - 1550-7998
UR  - http://arxiv.org/abs/1304.0483
UR  - https://doi.org/10.1103/PhysRevD.88.054507
DO  - 10.1103/PhysRevD.88.054507
LA  - English
N1  - WOS:000324636100005
ID  - Alvarez-Ruso_etal2013
ER  -