High statistics analysis using anisotropic clover lattices: IV. Volume dependence of light hadron masses

The volume dependence of the octet baryon masses and relations among them areexplored with Lattice QCD. Calculations are performed with n_f=2+1 cloverfermion discretization in four lattice volumes, with spatial extent L ~ 2.0,2.5, 3.0 and 3.9 fm, with an anisotropic lattice spacing of b_s ~ 0.123 fm inthe spatial direction, and b_t = b_s/3.5 in the time direction, and at a pionmass of m_pi ~ 390 MeV. The typical precision of the ground-state baryon massdetermination is ~0.2%, enabling a precise exploration of the volume dependenceof the masses, the Gell-Mann--Okubo mass relation, and of other masscombinations. A comparison of the volume dependence with the predictions ofheavy baryon chiral perturbation theory is performed in both the SU(2)_L XSU(2)_R and SU(3)_L X SU(3)_R expansions. Predictions of the three-flavorexpansion for the hadron masses are found to describe the observed volumedependences reasonably well. Further, the Delta-N-pi axial coupling constant isextracted from the volume dependence of the nucleon mass in the two-flavorexpansion, with only small modifications in the three-flavor expansion from theinclusion of kaons and etas. At a given value of m_pi L, the finite-volumecontributions to the nucleon mass are predicted to be significantly smaller atm_pi ~ 140 MeV than at m_pi ~ 390 MeV due to a coefficient that scales as ~m_pi^3. This is relevant for the design of future ensembles of latticegauge-field configurations. Finally, the volume dependence of the pion and kaonmasses are analyzed with two-flavor and three-flavor chiral perturbationtheory.Comment: 34 pages, 45 figure