ar X iv : h ep - p h / 02 01 29 7 v 1 3 1 Ja n 20 02
نویسنده
چکیده
We compute the hadronic light-by-light scattering contributions to the muon anomalous magnetic moment, a μ (had), in chiral perturbation theory. We obtain the model-independent, leading and subleading logarithmic contributions to this quantity, whose sum depends on a low-energy constant entering pseudoscalar meson decay into a charged lepton pair. The uncertainty introduced by this constant is comparable in magnitude to the uncertainty entering the leading-order vacuum polarization contributions to the anomalous moment. It may be reduced to some extent through an improved measurement of the π → ee branching ratio. However, the dependence of a μ (had) on non-logarithmically enhanced effects cannot be constrained except through the measurement of the anomalous moment itself. The extraction of information on new physics would require a future experimental value for the anomalous moment differing significantly from the result originally reported by the E821 collaboration. Typeset using REVTEX
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