Precision Observables in the MSSM: Leading Electroweak Two-loop Corrections

الأصل · EN

The leading electroweak MSSM two-loop corrections to the ρ-parameter are calculated. They are obtained by evaluating the two-loop self-energies of the Z and the W boson at O(Gf² mₜ⁴) in the limit of heavy scalar quarks. A very compact expression is derived, depending on the ratio of the CP-odd Higgs boson mass, Mₐ, and the top quark mass, mₜ. Expressions for the limiting cases Mₐ >> mₜ and Mₐ << mₜ are also given. The decoupling of the non-SM contribution in the limit Mₐ -> oo is verified at the two-loop level. The numerical effect of the leading electroweak MSSM two-loop corrections is analyzed in comparison with the leading corrections of O(Gf² mₜ⁴) in the SM and with the O(alpha alphaₛ) corrections in the MSSM.