https://doi.org/10.1051/epjconf/20147304015
Nucleon mass and pion-nucleon sigma term from a chiral analysis of lattice QCD world data
1 Instituto de Física Corpuscular (IFIC), Centro Mixto Universidad de Valencia-CSIC, Valencia, Spain
2 Departamento de Física Teórica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Valencia, Spain
3 Department of Physics and Astronomy, University of Sussex, Brighton, UK
a e-mail: ledwig@ific.uv.es
Published online: 9 June 2014
The chiral behavior of the nucleon mass is studied within the covariant SU(2) baryon chiral perturbation theory up to order p4. Lattice QCD data for the ensembles of 2 and 2 + 1 flavors are separately fitted, paying special attention to explicit Δ(1232) degrees of freedom, finite volume corrections and finite spacing effects. In the case of the 2 flavor ensemble, we fit simultaneously nucleon mass data together with new and updated data for the σπN term both in their dimensionless forms and determine a Sommer-scale of r0 = 0.493(23) fm. We obtain low-energy constants of natural size that are compatible with the rather linear pion-mass dependence observed in lattice QCD and report a preliminary updated value of σπN = 43(5)(4) MeV for the 2 flavor case and σπN = 52(3)(8) MeV for 2 + 1 flavor case.
© Owned by the authors, published by EDP Sciences, 2014
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
