Quantum effects on $t\rightarrow H^{+}\,b$ in the MSSM: a window to “virtual” supersymmetry?

Abstract

We analyze the one-loop effects (strong and electroweak) on the unconventional top quark decay mode t → H + b within the MSSM. The results are presented in the on-shell renormalization scheme with a physically well motivated definition of tan β. The study of this process at the quantum level is useful to unravel the potential supersymmetric nature of the charged Higgs emerging from that decay. As compared with the standard mode t → W + b, the corrections to t → H + b are large, slowly decoupling and persist at a sizeable level even for all sparticle masses well above the LEP 200 discovery range. As a matter of fact, the potential size of the SUSY effects, which amount to corrections of several ten percent, could counterbalance the standard QCD corrections and even make them to appear with the "wrong" sign. Therefore, if the charged Higgs decay of the top quark is kinematically allowed -a possibility which is not excluded by the recent measurements of the branching ratio BR(t → W + b) at the Tevatron -it could be an invaluable laboratory to search for "virtual" supersymmetry. While a first significant test of these effects could possibly be performed at the upgraded Tevatron, a more precise verification would most likely be carried out in future experiments at the LHC.

On MSSM charged Higgs-boson production in association with an electroweak W boson at electron–positron colliders

“…[16], the application of which to W ± -H ∓ self-energies is discussed in detail in Ref. [17]. In the MSSM no new types of divergent vertex functions occur.…”

Detecting heavy charged Higgs bosons at the LHC with triple b-tagging

“…(Of course this has no significant impact on the signal since this branching fraction amounts to > ∼ 80% over most of the parameter space of our interest.) The effects of SUSY QCD corrections may be larger, depending on the SUSY parameters [17]. We shall neglect this by assuming a large SUSY mass scale ∼ 1 TeV.…”

Neutral Higgs-pair production at linear colliders within the general two-Higgs-doublet model: Quantum effects and triple Higgs boson self-interactions

“…In contrast, the general 2HDM accommodates trilinear Higgs couplings with great potential enhancement. The full list is displayed in Table II. As can be seen, the couplings in this table depend on the 7 free parameters (9). In the particular case where λ 5 = λ 6 , this table reduces to Table 1 of Ref.…”

“…The bulk of the enhancing capabilities of the MSSM Lagrangian is concentrated, instead, in the rich structure of Yukawa-like couplings between Higgs bosons and quarks or between Higgs boson and squarks, or even between squarks and chargino-neutralinos, as it was shown long ago in plentiful phenomenological scenarios involving quantum effects on the gauge boson masses [6,7] and gauge boson and top quark widths [8], as well as in many other processes and observables (see e.g. [9][10][11][12][13]. For the present state of the art, cf.…”