Higgs alignment from extended supersymmetry

Abstract

We consider the effective type-II two-Higgs doublet model originating from Dirac gaugino models with extended supersymmetry in the gauge sector, which is automatically aligned in the simplest realisations. We show that raising the scale at which the extended supersymmetry is manifest and including quantum corrections actually improves the alignment. Using an effective field theory approach including new threshold corrections and two-loop RGEs, plus two-loop corrections to the Higgs mass in the low-energy theory, we study the implications from the Higgs mass and other experimental constraints on the scale of superpartners. We contrast the results of the minimal Dirac gaugino model, where alignment is automatic, with the hMSSM and the MRSSM, where it is not, also providing an hMSSM-inspired analysis for the new models.

LHC limits on gluinos and squarks in the minimal Dirac gaugino model

“…An N = 2 SUSY in turn leads automatically to alignment [12] due to the SU (2) R-symmetry of the two Higgs doublets (which form an N = 2 hypermultiplet) [13]. This alignment is surprisingly robust under quantum corrections, where there is an accidental cancellation of N = 2 breaking effects [12]. Moreover, it has been found that the R-symmetry also prevents chiralityflip diagrams, which significantly relaxes flavour constraints [14][15][16] and suppresses squark production at the LHC, rendering DG models "supersafe" [17][18][19][20].…”

R-symmetry for Higgs alignment without decoupling

“…These results also allow us to understand why the simple identification of couplings in the Higgs couplings with their N = 2 expected values, as it was attempted for the MRSSM in [3], fails to achieve alignment. There, the integration out of the additional doublets breaks the SU (2) R R-symmetry explicitly at tree level.…”

Predicting Alignment in a Two Higgs Doublet Model

“…as given in [4,6]. Again, restricting to the case of CP conserving Lagrangian, the two CP even scalars have squared-mass matrix (2.10) with…”

“…Such an alignment without decoupling [1] was realized in [2] ( see the discussion of the spectrum in Section 3 of [2], the model was not engineered for this purpose but as a scenario for supersymmetry breaking, and therefore we can consider the alignment there as a "prediction" of the model) and discussed later in [3,4]. In particular, it was shown in [4] that the alignment survives with an impressive precision when radiative corrections are taken into account. The mechanisms behind this successful alignment are a combination of a global SU (2) R symmetry of the quartic potential and diverse cancellations due to supersymmetry as discussed in [5] and will be reviewed here.…”

“…We find that the misalignment comes from the squark corrections are compensated by the effect of running λ S , λ T . The numerical results are shown inFigure 1, taken from[4]. Z 6 (Q) at the low energy scale Q against tan β for the N = 2 scale M N =2 = M SUSY , 10 10 GeV and 10 16 GeV[4].…”