One loop radiative corrections to $e^+e^-\to H^+ H^-$ are considered at future linear collider energies, in the general type II Two Higgs Doublet Model (THDM) and in the Minimal Supersymmetric Standard Model-like (MSSM) Higgs sector. To make the comparison between THDM and MSSM tractable, we have introduced a quasi-SUSY parameterization which preserves all the tree-level Higgs mass-sum-rules of the MSSM, and involves just 3 free parameters in the Higgs sector (instead of 7 in the general THDM) and comprises the MSSM as a particular case. The model-independent soft photon contribution is isolated and shown to be substantial. Important effects come also from the contribution of the model dependent $h^0 H^+ H^-$ and $H^0 H^+ H^-$ vertices to the final state. In the MSSM, the contribution of the Higgs sector is moderate (a few percent) while in the THDM and both for small and large $\tan β$ important effects ($\sim +30%$) can be found.
Recently, the Higgs boson masses in the Minimal Supersymmetric Standard Model (MSSM) and their mixing have been calculated using the complex Two-Higgs-DoubletModel (cTHDM) as an effective field theory (EFT) of the MSSM. Here, we discuss the implementation of this calculation, which we improve in several aspects, into the hybrid framework of FeynHiggs by combing the cTHDM-EFT calculation with the existing fixed-order calculation. This combination allows accurate predictions also in the intermediate regime where some SUSY particles are relatively light, some relatively heavy and some in between.…
We study the loop induced production of charged Higgs boson associated with W-boson via photon-photon collisions at linear colliders (LC). The investigation is carried out under the two-Higgs-doublet model(THDM) and the minimal supersymmetric model (MSSM) using full on-mass-shell renormalization scheme. The numerical analysis of their production rates is presented with some typical parameter sets. The results show that the total cross sections in frame of the MSSM at linear colliders(LC) can reach 0.1 femto barn quantitatively. The contributions from supersymmetric sector can lead to an order …
Possible models of Yukawa interaction are discussed in the two Higgs doublet model (THDM) under the discrete symmetry imposed to avoid the flavor changing neutral current at the leading order. It is known that there are four types of such models corresponding to the possible different assignment of charges for the discrete symmetry on quarks and leptons. We first examine decay properties of Higgs bosons in each type of the models, and summarize constraints on the models from current experimental data. We then shed light on the differences among these models in collider phenomenology. In partic…
We present results of a calculation of the cross section for the production of a charged Higgs boson in association with an electron and a neutrino at electron-positron colliders (e+ e- -> H+ e- nu_e-bar, H- e+ nu_e). We study predictions for the cross section in the Minimal Supersymmetric Standard Model (MSSM) and the Two Higgs Doublet Model (THDM), highlighting possible differences. The process is effectively loop-induced in both models. Hence, the cross section is expected to be strongly model-dependent. Most notably, due to the presence of superpartners, the MSSM amplitude contains Feynman…
We study the associated production of the A^0 neutral CP-odd Higgs boson with a neutral gauge boson Z in high energy e^+ e^- collisions at the one loop level. We present a detailed discussion for the total cross-section predicted in the context of the Minimal Supersymmetric Standard Model (MSSM) and make a comparison with the non-SUSY Two Higgs Doublet Model (THDM). We show that the MSSM cross-section may be enhanced compared to that for the THDM.
We discuss the associated W+/- H-/+ production at the CERN Large Hadron Collider. The dependence of the hadronic cross section on the Higgs sector parameters is investigated in detail in the framework of the general Two Higgs Doublet Model (THDM). We study the possible enhancement of the THDM prediction for the cross section compared to the prediction of the Minimal Supersymmetric Standard Model (MSSM). We find regions in the THDM parameter space where the THDM prediction can exceed the one of the MSSM by two orders of magnitude. These regions of large cross section are in agreement with theor…
We discuss quantum corrections of new physics to the triple coupling of the lightest CP-even Higgs boson in the Two Higgs Doublet Model (THDM) and also in the Minimal Supersymmetric Standard Model (MSSM). In the THDM, quartic contributions of the mass of heavy particles in the loop can appear, which are not absorbed by renormalization of the Higgs boson mass. Such non-decoupling effects on the self-coupling can give corrections of ${\cal O}(100%)$, even when all measured Higgs couplings with gauge bosons and fermions are consistent with the Standard Model prediction. In the MSSM, the loop-corr…
We present a calculation of the cross section for the process e+ e- --> W+/- H-/+ in the minimal supersymmetric standard model (MSSM) and the Two Higgs Doublet Model (THDM). We study the basic features of the MSSM prediction for some distinctive parameter scenarios. We find large effects from virtual squarks for scenarios with large mixing in the stop sector which can lead to a cross section vastly different from a THDM with identical Higgs sector parameters. We investigate this interesting behaviour in more detail by thoroughly scanning the MSSM parameter space for regions of large cross sect…
Precise predictions for Higgs boson masses in the Minimal Supersymmetric Standard Model can be obtained by combining fixed-order calculations with effective field theory (EFT) methods for the resummation of large logarithms in case of heavy superpartners. This hybrid approach is implemented in the computer code FeynHiggs and has been applied in previous studies for calculating the mass of the lightest CP-even Higgs boson for low, intermediate and high SUSY scales. In these works it was assumed that the non-standard Higgs bosons share a common mass scale with the supersymmetric squark particles…
The Higgs sectors of supersymmetric extensions of the Standard Model have two doublets in the minimal version (MSSM), and two doublets plus a singlet in two others: with (UMSSM) and without (NMSSM) an extra U(1)'. A very concise comparison of these three models is possible if we assume that the singlet has a somewhat larger breaking scale compared to the electroweak scale. In that case, the UMSSM and the NMSSM become effectively two-Higgs-doublet models (THDM), like the MSSM. As expected, the mass of the lightest CP-even neutral Higgs boson has an upper bound in each case. We find that in the …
We study the 1-loop corrections to the charged Higgs production both in the Minimal Supersymmetric Standard Model (MSSM) and in a more general type II two-Higgs-doublet model (THDM-II). We consider the full set of corrections (including soft photon contributions as well as box diagrams), and define a parametrization that allows a comparison between the two models. Besides the soft photon radiation there can be prominent model-dependent effects.
We discuss the phenomenology of the lightest stops in models where R-parity is broken by bilinear terms. In this class of models we consider scenarios where the R-parity breaking two-body decay stop_1 -> tau + b competes with the leading three-body decays stop_1 -> W^+ + b + neutralino_1, H^+ + b + neutralino_1, b slepton^+_i neutrino_l, b sneutrino_l l^+ (l=e, mu, tau). We demonstrate that the R-parity violating decay can be the dominant one. In particular we focus on the implications for a future electron posistion Linear Collider.
We revisit the production of a single Higgs boson from direct γγ-scattering at a photon collider. We compute the total cross section σ(γγ\to h) (for h=h0, H0, A0), and the strength of the effective g_{h γγ} coupling normalized to the Standard Model (SM), for both the general Two-Higgs-Doublet Model (2HDM) and the Minimal Supersymmetric Standard Model (MSSM). In both cases the predicted production rates for the CP-even (odd) states render up to 10^4 (10^3) events per 500 \invfb of integrated luminosity, in full consistency with all the theoretical and phenomenological constraints. Depending on …
We investigate the general question of implementing a chiral MSSM like D-brane sector in Type IIB orientifold models with complete moduli stabilisation via F-terms induced by fluxes and space-time instantons, respectively gaugino condensates. The prototype examples are the KKLT and the so-called large volume compactifications. We show that the ansatz of first stabilising all moduli via F-terms and then introducing the Standard Model module is misleading, as a chiral sector notoriously influences the structure of non-perturbative effects and induces a D-term potential. Focusing for concreteness…
In this paper, we investigate sizeable interference effects between a heavy charged Higgs boson signal produced via $gg\to t\bar b H^-$ (+ c.c.) followed by the decay $H^-\to b\bar t$ (+ c.c.) and the irreducible background given by $gg\to t\bar t b \bar b$ topologies at the Large Hadron Collider (LHC). We show how such effects could spoil current $H^\pm$ searches where signal and background are normally treated separately. The reason for this is that a heavy charged Higgs boson can have a large total width, in turn enabling such interferences, altogether leading to very significant alteration…
One of the challenging tasks at future experiments is the clear identification of the underlying new physics model. In this study we concentrate on the distinction between different supersymmetric models, the MSSM and the NMSSM, exploring the gaugino/higgsino sector as an alternative to the Higgs sector. Under the assumption that only the light chargino and neutralino masses and polarized cross sections $e^+e^-\to \tildeχ^0_i\tildeχ^0_j$, $\tildeχ^+_i\tildeχ^-_j$ have been measured, we perform a fit of the fundamental MSSM parameters $M_1$, $M_2$, $μ$ and $\tanβ$ and study whether a model dist…
We quantify and examine the uncertainties in predictions of the lightest $CP$ even Higgs boson pole mass $M_h$ in the Minimal Supersymmetric Standard Model (MSSM), utilising current spectrum generators and including some three-loop corrections. There are two broadly different approximations being used: effective field theory (EFT) where an effective Standard Model (SM) is used below a supersymmetric mass scale, and a fixed order calculation, where the MSSM is matched to QCD$\times$QED at the electroweak scale. The uncertainties on the $M_h$ prediction in each approach are broken down into loga…
The signal strength of the recently discovered Higgs boson-like particle in the diphoton channel seemingly constrains physics beyond the standard model to a severe degree. However, the reported signal strength is prone to possible underestimation of uncertainties. We propose a discriminant that is relatively free of many of the theoretical uncertainties, and use this to gauge the impact on the phenomenological MSSM. A Bayesian global fit to all the pre-LHC data results in posterior distributions for the masses that are neither very restrictive, nor sufficiently prior-independent (except for th…
The production of triple Higgs $(H^+H^-H^0)$, $(H^+H^-h^0)$ and pair wise charged Higgs boson $(H^+H^-)$ is studied in the context of future linear colliders within the Two-Higgs Doublet Model (2HDM) type II. The aim is to compare sources of charged Higgs pair through the above processes, i.e., double and triple Higgs production. Cross-sections are calculated at the leading order in 2HDM type II and Minimal Supersymmetric Standard Model (MSSM). Several orders of magnitude ($\sim 10^{4}$) enhancement is observed in 2HDM compared to MSSM, while no sizable enhancement is seen in muon collider ver…
Assuming that the axion mechanism of solving the strong CP problem does not exist and the vanishing of theta at tree level is achieved by some model-building means, we study the naturalness of having large CP-violating sources in the leptonic sector. We consider the radiative mechanisms which transfer a possibly large CP-violating phase in the leptonic sector to the theta parameter. It is found that large theta cannot be induced in the models with one Higgs doublet as at least three loops are required in this case. In the models with two or more Higgs doublets the dominant source of theta is t…
We present an updated overview on the phenomenology of one-loop Higgs boson production at Linear Colliders within the general Two-Higgs-Doublet Model (2HDM). First we report on the Higgs boson pair production, and associated Higgs-Z boson production, at O(alpha^3_{ew}) from e+e- collisions. These channels furnish cross-sections in the range of 10-100 fb for Ecm=0.5 TeV and exhibit potentially large radiative corrections (of order 50%), whose origin can be traced back to the genuine enhancement capabilities of the triple Higgs boson self-interactions. Next we consider the loop-induced productio…
We consider the possibility that after operations at the LHC and e^+e^- Linear Colliders a Higgs boson will be discovered, but no signal of New Physics will be found (Standard-Model-like scenario). This can occur in the Standard Model (SM) as well as in other models, including the Two-Higgs-Doublet Model (2HDM), the MSSM, etc. Experiments at a Photon Collider can resolve these cases. In this paper we compare the SM and the 2HDM~(II). In the analysis we use as independent quantities the ratios, to the SM values, of couplings of the observed Higgs boson to gauge bosons, and to up and down-type q…
The Triplet extension of the MSSM (TMSSM) alleviates the little hierarchy problem and provides a significant enhancement of the loop-induced diphoton rate of the lightest CP-even Higgs h. In this paper we pursue the analysis of the TMSSM Higgs phenomenology by computing for the first time the h into Z + gamma decay. Interestingly we find that the rates of loop-induced decays are correlated and their signal strengths can rise up to 40% - 60% depending on the channel. We furthermore study the dark matter phenomenology of the TMSSM. The lightest neutralino is a good dark matter candidate in two r…
Assuming that a non-standard neutral Higgs with an enhanced Yukawa coupling to a bottom quark is observed at future hadron experiments, we propose a method for a better understanding of the Higgs sector. Our procedure is based on "counting" the number of events with heavy jets (where "heavy" stands for a c or b jet) versus b jets, in the final state of processes in which the Higgs is produced in association with a single high p_T c or b jet. We show that an observed signal of the type proposed, at either the Tevatron or the LHC, will rule out the popular two Higgs doublet model of type II as w…
