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arXiv · 1206.7034

Nucleon mass and sigma term from lattice QCD with two light fermion flavors

G. S. Bali·P. C. Bruns·S. Collins·M. Deka·B. Gläßle·M. Göckeler·L. Greil·T. R. Hemmert·R. Horsley·J. Najjar·Y. Nakamura·A. Nobile·D. Pleiter·P. E. L. Rakow·A. Schäfer·R. Schiel·G. Schierholz·A. Sternbeck·J. Zanotti
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Abstract

We analyze Nf=2 nucleon mass data with respect to their dependence on the pion mass down to mpi = 157 MeV and compare it with predictions from covariant baryon chiral perturbation theory (BChPT). A novel feature of our approach is that we fit the nucleon mass data simultaneously with the directly obtained pion-nucleon sigma-term. Our lattice data below mpi = 435 MeV is well described by O(p^4) BChPT and we find sigma=37(8)(6) MeV for the sigma-term at the physical point. Using the nucleon mass to set the scale we obtain a Sommer parameter of r_0=0.501(10)(11) fm.

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G. S. Bali, P. C. Bruns, S. Collins, M. Deka, B. Gläßle, M. Göckeler, L. Greil, T. R. Hemmert, R. Horsley, J. Najjar, Y. Nakamura, A. Nobile, D. Pleiter, P. E. L. Rakow, A. Schäfer, R. Schiel, G. Schierholz, A. Sternbeck, J. Zanotti. 2012-06-29. Nucleon mass and sigma term from lattice QCD with two light fermion flavors. https://doi.org/10.1016/j.nuclphysb.2012.08.009

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