Hard supersymmetry-breaking “wrong-Higgs” couplings of the MSSM

In the minimal supersymmetric extension of the standard model (MSSM), if the two-Higgs doublets are lighter than some subset of the superpartners of the standard model particles, then it is possible to integrate out the heavy states to obtain an effective broken-supersymmetric low-energy Lagrangian. This Lagrangian can contain dimension-four gauge-invariant Higgs interactions that violate supersymmetry (SUSY). The wrong-Higgs Yukawa couplings generated by one-loop radiative corrections are a well-known example of this phenomenon. In this paper, we examine gauge-invariant gaugino-higgsino-Higgs boson interactions that violate supersymmetry. Such wrong-Higgs gaugino couplings can be generated in models of gauge-mediated SUSY-breaking in which some of the messenger fields couple to the MSSM Higgs bosons. In regions of parameter space where the messenger scale is low and $\tan \beta$ is large, these hard SUSY-breaking operators yield $\tan \beta$-enhanced corrections to tree-level supersymmetric relations in the chargino and neutralino sectors that can be as large as 56%. We demonstrate how physical observables in the chargino sector can be used to isolate the $\tan \beta$-enhanced effects derived from the wrong-Higgs gaugino operators.

Figure 1

One-loop diagrams contributing to the wrong-Higgs-Yukawa effective operators. In (a), the cross ($\times$) corresponds to a factor of the gluino mass $M_3$. In (b), the cross corresponds to a factor of the higgsino Majorana mass parameter $\mu$. Field labels correspond to annihilation of the corresponding particle at each vertex of the triangle.

Figure 2

One-loop diagrams contributing to the wrong-Higgs gaugino effective operators. The cross ($\times$) indicates the two-component fermion propagator that is proportional to the corresponding Dirac mass. In (a) and (b) the solid dot indicates an insertion of the Higgs vacuum expectation value. Field labels correspond to annihilation at each vertex of the triangle.

Figure 3

One-loop diagrams with internal lines consisting of scalar and fermionic messenger fields. The cross ($\times$) indicates the two-component fermion propagator that is proportional to the corresponding Dirac mass. The solid dot indicates an $F_Z$ mass-insertion on the scalar messenger line.