title: Hadronic light-by-light contribution to muon g - 2 in chiral perturbation theory.
abstract: We compute the hadronic light-by-light scattering contributions to the muon anomalous magnetic moment, a(LL)(mu)(had), in chiral perturbation theory that are enhanced by large logarithms and a factor of N(C). They depend on a low-energy constant constrained by eta-->mu(+) mu(-) and pi(0)-->e(+)e(-) branching ratios. However, the dependence of a(LL)(mu)(had) on nonlogarithmically enhanced effects cannot be constrained except through the measurement of the anomalous moment itself.
authors.affiliation: California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Ramsey-Musolf
authors.forename: Mark B
authors.initials: MB
authors.lastname: Wise