出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We calculate the electromagnetic contribution to the pion mass difference, Dm2p = m2 p+ −m2p0 ,
in the chiral limit through the VV −AA type vacuum polarization using Das-Guralnik-Mathur-
Low-Young (DGMLY) sum rule. The calculation is made with two-flavors of dynamical overlap
fermions on a 163 × 32 lattice at a ∼0.12 fm. The exact chiral symmetry of the overlap
fermion is essential to control the systematic error in the difference VV −AA. We obtain
Dm2p = 1024(100)MeV2 combining the lattice data with the perturbative contribution in the high
momentum region evaluated by the operator product expansion. By analyzing the momentum dependence
of the vacuum polarization, we also obtain pion decay constant fp and the low-energy
constants Lr
10 in the chiral limit.
