6533b834fe1ef96bd129e2ca
RESEARCH PRODUCT
The nucleon mass and pion-nucleon sigma term from a chiral analysis ofNf= 2 lattice QCD world data
J. Martin CamalichLuis Alvarez-rusoM. J. Vicente VacasT. Ledwigsubject
PhysicsParticle physicsChiral perturbation theoryPhysicsQC1-999High Energy Physics::LatticeHigh Energy Physics::PhenomenologyLattice field theoryDegrees of freedom (physics and chemistry)Lattice QCDBaryonPionNucleonSpecial unitary groupdescription
We investigate the pion-mass dependence of the nucleon mass within the covariant SU (2) baryon chiral perturbation theory up to order p 4 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 N f = 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 r 0 = 0.493(23) fm and also include one σ π N lQCD data point at M π ≈ 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 σ π N = 41(5)(4) MeV for the 2 flavor case and σ π N = 52(3)(8) MeV for 2+1 flavors.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2014-03-01 | EPJ Web of Conferences |