2026-04-17T06:57:33Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/1316882025-12-05T16:59:01Zcom_2072_1057col_2072_478823col_2072_478904col_2072_478917

00925njm 22002777a 4500 dc Detmold, William author Savage, Martin J. author Torok, Aaron author Beane, Silas R. author Luu, Thomas C. author Orginos, Kostas author Parreño García, Assumpta author NPLQCD Collaboration author 2019-04-05T14:13:24Z 2019-04-05T14:13:24Z 2008-07-18 2019-04-05T14:13:24Z The ground-state energies of systems containing up to 12 π + 's in a spatial volume V ∼ ( 2.5     fm ) 3 are computed in dynamical, mixed-action lattice QCD at a lattice spacing of ∼ 0.125     fm for four different values of the light-quark masses. Clean signals are seen for each ground-state, allowing for a precise extraction of both the π + π + scattering length and π + π + π + interaction from a correlated analysis of systems containing different numbers of π + 's. This extraction of the π + π + scattering length is consistent with that from the π + π + system alone. The large number of systems studied here significantly strengthens the arguments presented in our earlier work and unambiguously demonstrates the presence of a low energy π + π + π + interaction. The equation of state of a π + gas is investigated using our numerical results and the density dependence of the isospin chemical potential for these systems agrees well with the theoretical expectations of leading order chiral perturbation theory. The chemical potential is found to receive a substantial contribution from the π + π + π + interaction at the lighter pion masses. An important technical aspect of this work is the demonstration of the necessity of performing propagator contractions in greater than double precision to extract the correct results. Física de partícules Hadrons Particle physics Hadrons Multipion states in lattice QCD and the charged-pion condensate