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Leading QCD Corrections to Scalar Quark Contributions to Electroweak Precision Observables

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

In the supersymmetric extension of the Standard Model we derive the two-loop QCD corrections to the scalar quark contributions to the electroweak precision observables entering via the rho parameter. A very compact expression is derived for the gluon-exchange contribution. The complete analytic result for the gluino-exchange contribution is very lengthy; we give expressions for several limiting cases that were derived from the general result. The two-loop corrections, generally of the order of 10 to 30% of the one-loop contributions, canbe very significant. Contrary to the Standard Model case, where the QCD corrections are negative and screen the one-loop value, the corresponding corrections in the supersymmetric case are in general positive, therefore 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. 1997-10-22. Leading QCD Corrections to Scalar Quark Contributions to Electroweak Precision Observables. https://doi.org/10.1103/physrevd.57.4179

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