We calculate distributions for ττγ production at LEP 1 taking into account a potentially existing anomalous magnetic moment aτ of the τ lepton. The existing upper limits for |aτ | are known from the dependence of the decay Z → ττγ on a2τ and are of the order of (1− 5)%. We show that such limits are also sensitive to linear terms in aτ , which are of equal importance at |aτ | ∼ (1− 2)% and domin...

We study the muon anomalous magnetic dipole moment in supersymmetric theories. The impact of the recent Brookhaven E821 experimental measurement on both modelindependent and model-dependent supersymmetric parameter spaces is discussed in detail. We find that values of tanβ as low as 3 can be obtained while remaining within the E821 one-sigma bound. This requires a light smuon; however, we show ...

We compute the three-loop QCD corrections to the quark chromomagnetic moment and thus obtain the matching coefficient and the anomalous dimension of the chromomagnetic interaction in HQET. As a byproduct we obtain the three-loop corrections to the quark anomalous magnetic moment.

We study the naturalness, dark matter, and muon anomalous magnetic moment in the Supersymmetric Standard Models (SSMs) with a pseudo-Dirac gluino (PDGSSMs) from hybrid F− and D−term supersymmetry (SUSY) breakings. To obtain the observed dark matter relic density and explain the muon anomalous magnetic moment, we find that the low energy fine-tuning measures are larger than about 200 due to stro...

We study the effects of extra dimensions on the muon anomalous magnetic moment with brane fluctuation. Since the coupling is naturally suppressed if brane fluctuation is considered by exponential softening factor for heavier states, the contribution from the whole Kaluza-Klein graviton tower is shown to be finite. The recent BNL E821 result is accomodated with D = 4 + δ dimensional gravitationa...

The recent measurement of the muon anomalous magnetic moment am shows a 2.6s deviation from the standard model value. We show that it puts an interesting bound on the mass of the second generation leptoquarks. To account for the data the leptoquark must have both leftand right-handed couplings to the muon. Assuming that the couplings have electromagnetic strength, the mass is restricted in the ...

We compute the contributions to the electron and muon anomalous magnetic moment induced by heavy leptons up to four-loop order. Asymptotic expansion is applied to obtain three analytic expansion terms which show rapid convergence. PACS numbers: 12.20.-m 14.60.Cd 14.60.Ef

The E821 experiment at Brookhaven National Laboratory is designed to measure the muon magnetic anomaly, aμ, to an ultimate precision of 0.4 parts per million (ppm). Because theory can predict aμ to 0.6 ppm, and ongoing efforts aim to reduce this uncertainty, the comparison represents an important and sensitive test of new physics. At the time of this Workshop, the reported experimental result f...