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 (SM) and derive the associated O(αs) correction to the ρ parameter. 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.

Supersymmetric Contributions to Electroweak Precision Observables: QCD Corrections

GAMBINO, Paolo;
1997-01-01

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 (SM) and derive the associated O(αs) correction to the ρ parameter. 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.
1997
78
3626
3629
http://prl.aps.org/abstract/PRL/v78/i19/p3626_1
A. Djouadi; P. Gambino; S. Heinemeyer; W. Hollik; C. Jünger; G. Weiglein
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/105052
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