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arXiv · hep-ph/9612363

Supersymmetric contributions to electroweak precision observables: QCD corrections

A. Djouadi·P. Gambino·S. Heinemeyer·W. Hollik·C. Jünger·G. Weiglein
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Abstract

We calculate the two-loop QCD correction to the scalar quark contributions to the electroweak gauge-boson self-energies at zero momentum-transfer in the supersymmetric extension of the Standard Model. We then derive the $O(α_s)$ correction to the contribution of the scalar top and bottom quark loops to the rho parameter, which is the most sizable supersymmetric contribution to the electroweak mixing angle and the W-boson mass. The two-loop corrections modify the one-loop contribution by up to 30%; the gluino decouples for large masses. Contrary to the SM case where the QCD corrections are negative and screen the one-loop value, the corresponding corrections in the supersymmetric case are in general positive, increasing the sensitivity in the search for scalar quarks through their virtual effects in high-precision electroweak observables.

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A. Djouadi, P. Gambino, S. Heinemeyer, W. Hollik, C. Jünger, G. Weiglein. 1996-12-14. Supersymmetric contributions to electroweak precision observables: QCD corrections. https://doi.org/10.1103/physrevlett.78.3626

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