出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We determine the strong-isospin violating component of the neutron-proton mass difference from
fully-dynamical lattice QCD and partially-quenched QCD calculations of the nucleon mass, constrained
by partially-quenched chiral perturbation theory at one-loop level. The lattice calculations
were performed with domain-wall valence quarks on MILC lattices with rooted staggered
sea-quarks at a lattice spacing of b 0:125 fm, lattice spatial size of L 2:5 fm and pion masses
ranging from mp 290 MeV to 350 MeV. At the physical value of the pion mass, we predict
MnMpj(du) =2:260:570:420:10MeV where the rst error is statistical, the second error
is due to the uncertainty in the ratio of light-quark masses, h = mu=md, determined by MILC [1],
and the third error is an estimate of the systematic due to chiral extrapolation.
