Dominik Stöckinger

Electroweak and supersymmetric two-loop corrections to (g−2)μ

Abstract We present the up to now most precise evaluation of electroweak and supersymmetric contributions to the anomalous magnetic moment of the muon a μ , describing in detail also the calculational techniques. We calculate the bosonic two-loop contributions in the Standard Model without the approximation of a heavy Higgs-boson mass, finding corrections up to 0.2 × 10 − 10 for a light Higgs boson. In the Minimal Supersymmetric Standard Model the corresponding two-loop contributions from the two-Higgs-doublet model part differ from the Standard Model result by up to 0.3 × 10 − 10 . Finally, we evaluate the diagrams where a loop of charginos or neutralinos, the superpartners of gauge and Higgs bosons, is inserted into a two-Higgs-doublet one-loop diagram. These corrections can amount up to 10 × 10 − 10 , which is almost 2 σ of the current experimental uncertainty.

Two-Loop SUSY Corrections to the Anomalous Magnetic Moment of the Muon

Abstract We calculate supersymmetric two-loop corrections to the anomalous magnetic moment of the muon, consisting of diagrams with a closed scalar fermion or fermion loop and gauge and/or Higgs boson exchange. We discuss the numerical impact of each subclass of diagrams and determine the leading contributions. We analyze in detail constraints from experimental information on the Higgs boson mass, Δ ρ , and the branching ratios of B → X s γ and B s → μ + μ − . If these constraints are taken into account, the largest possible effect of our two-loop corrections is reduced from more than 3 σ (in terms of the current experimental error) to ∼0.5 σ , such that the influence on the total supersymmetric prediction is smaller than previously estimated. However, exceptions arise in rather extreme parameter scenarios with a strong non-universality between the soft breaking parameters in the stop and sbottom sectors.

Regularization by dimensional reduction: consistency, quantum action principle, and supersymmetry

It is proven by explicit construction that regularization by dimensional reduction can be formulated in a mathematically consistent way. In this formulation the quantum action principle is shown to hold. This provides an intuitive and elegant relation between the D-dimensional lagrangian and Ward or Slavnov-Taylor identities, and it can be used in particular to study to what extent dimensional reduction preserves supersymmetry. We give several examples of previously unchecked cases.It is proven by explicit construction that regularization by dimensional reduction can be formulated in a mathematically consistent way. In this formulation the quantum action principle is shown to hold. This provides an intuitive and elegant relation between the D-dimensional lagrangian and Ward or Slavnov-Taylor identities, and it can be used in particular to study to what extent dimensional reduction preserves supersymmetry. We give several examples of previously unchecked cases.It is proven by explicit construction that regularization by dimensional reduction can be formulated in a mathematically consistent way. In this formulation the quantum action principle is shown to hold. This provides an intuitive and elegant relation between the D-dimensional Lagrangian and Ward or Slavnov-Taylor identities, and it can be used in particular to study to what extent dimensional reduction preserves supersymmetry. We give several examples of previously unchecked cases.

The electroweak contributions to

The Higgs boson mass used to be the only unknown input parameter of the electroweak contributions to (g-2)_\mu\ in the Standard Model. It enters at the two-loop level in diagrams with e.g. top loops, W- or Z-exchange. We re-evaluate these contributions, providing analytic expressions and exact numerical results for the Higgs boson mass recently measured at the LHC. Our final result for the full Standard Model electroweak contributions is (153.6\pm1.0)*10^{-11}, where the remaining theory error comes from unknown three-loop contributions and hadronic uncertainties.

(g-2)_\mu

We present the currently most accurate evaluation of the W boson mass, MW, in the Minimal Supersymmetric Standard Model (MSSM). The full complex phase dependence at the one-loop level, all available MSSM two-loop corrections as well as the full Standard Model result have been included. We analyse the impact of the different sectors of the MSSM at the one-loop level with a particular emphasis on the effect of the complex phases. We discuss the prediction for MW based on all known higher-order contributions in representative MSSM scenarios. Furthermore we obtain an estimate of the remaining theoretical uncertainty from unknown higher-order corrections.

after the Higgs boson mass measurement

We present the currently most accurate evaluation of the W boson mass, MW, in the Minimal Supersymmetric Standard Model (MSSM). The full complex phase dependence at the one-loop level, all available MSSM two-loop corrections as well as the full Standard Model result have been included. We analyse the impact of the different sectors of the MSSM at the one-loop level with a particular emphasis on the effect of the complex phases. We discuss the prediction for MW based on all known higher-order contributions in representative MSSM scenarios. Furthermore we obtain an estimate of the remaining theoretical uncertainty from unknown higher-order corrections.

Precise prediction for M(W) in the MSSM

The renormalization of the Minimal Supersymmetric Standard Model is discussed. In particular we focus on the soft-supersymmetry breaking sector of the MSSM and comment on non-renormalization theorems.

Precise prediction for MW in the MSSM

A bstractWe complete the two-loop calculation of β-functions for vacuum expectation values (VEVs) in gauge theories by the missing

Renormalization of the minimal supersymmetric standard model

\mathcal{O}

Renormalization of vacuum expectation values in spontaneously broken gauge theories: two-loop results

(g4)-terms. The full two-loop results are presented for generic and supersymmetric theories up to two-loop level in arbitrary Rξ -gauge. The results are obtained by means of a scalar background field, identical to our previous analysis. As a by-product, the two-loop scalar anomalous dimension for generic supersymmetric theories is presented. As an application we compute the β-functions for VEVs and tan β in the MSSM, NMSSM, and E6SSM.