Muon anomalous magnetic moment and leptoquark solutions - art. no. 033001

The recent measurement of the muon anomalous magnetic moment a(mu) shows a 2.6 sigma deviation from the standard model value. We show that it puts an interesting bound on the mass of the second generation leptoquarks. To acco unt for the data the leptoquark must have both left- and right-handed coupl ings to the muon. Assuming that the couplings have electromagnetic strength , the mass is restricted in the range 0.7 TeV<M-LQ<2.2 TeV at 95% C.L. We a lso discuss constraints coming from other low energy and high energy experi ments. If first-second-generation universality is assumed, constraints come from atomic-parity violation and charged-current universality. We show tha t the coexistence with other leptoquarks can satisfy these additional const raints and at the same time does not affect a(<mu>).