The weak-magnetic moment of heavy quarks

With initial and final particles on-shell, the anomalous weak-magnetic dipole moments of b and c quarks are electroweak gauge invariant quantities of the effective couplings Zbb and Zcc, respectively, and good candidates to test the Standard Model and/or new physics. Here we present a complete computation of these quantities within the Standard Model. We show that decoupling properties with respect to heavy particles do take place in the weak magnetic moment. The obtained values, ab(MZ2) = (2.98 − 1.56i) × 10−4 and ac(MZ2) = (−2.80 + 1.09i) × 10−5 are dominated by one-gluon exchange diagrams. The electroweak corrections are less than 1% of the total magnitude.