Natural Two-Higgs-Doublet Model (original) (raw)
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4 Prepared for submission to JHEP Higgs Phenomenology in the Two-Singlet Model
2016
We study the phenomenology of the Standard Model (SM) Higgs sector extended by two singlet scalars. The model predicts two CP-even scalars h 1,2 which are a mixture of doublet and singlet components as well as a pure singlet scalar S 0 which is a dark matter candidate. We show that the model can satisfy the relic density and direct detection constraints as well as all the recent ATLAS and CMS measurements. We also discuss the effect of the extra Higgs bosons on the different Higgs triple couplings h i h j h k , i, j, k = 1, 2. A particular attention is given to the triple self-coupling of the SM-like Higgs where we found that the one loop corrections can reach 150% is some cases. We also discuss some production mechanisms for h 1 and h 2 at the LHC as well as at the future International Linear Collider. It is found that the production cross section of a pair of SM-like Higgs bosons could be much larger than the corresponding one in the SM and would reveal physics beyond the SM if observable. We also show that in this model the branching ratio of the SM-like Higgs decaying to two singlet scalars could be of the order of 20%, therefore the production of the SM Higgs followed by its decay to a pair of singlets would be an important source of production of singlet scalars.
Proceedings of 41st International Conference on High Energy physics — PoS(ICHEP2022)
Extensions of the Two Higgs Doublet model with a complex scalar singlet (2HDMS) can accommodate all current experimental constraints and are highly motivated candidates for Beyond Standard Model Physics. It can successfully provide a dark matter candidate as well as explain baryogenesis and provides gravitational wave signals. In this work, we focus on the dark matter phenomenology of the 2HDMS with the complex scalar singlet as the dark matter candidate. We study variations of dark matter observables with respect to the model parameters and present representative benchmark points in the light and heavy dark matter mass regions allowed by existing experimental constraints from dark matter, flavour physics and collider searches. We also compare real and complex scalar dark matter in the context of 2HDMS. Further, we discuss the discovery potential of such scenarios at the HL-LHC and at future e + e − colliders.
Higgs phenomenology in the two-singlet model
Journal of High Energy Physics, 2014
We study the phenomenology of the Standard Model (SM) Higgs sector extended by two singlet scalars. The model predicts two CP-even scalars h 1,2 which are a mixture of doublet and singlet components as well as a pure singlet scalar S 0 which is a dark matter candidate. We show that the model can satisfy the relic density and direct detection constraints as well as all the recent ATLAS and CMS measurements. We also discuss the effect of the extra Higgs bosons on the different Higgs triple couplings h i h j h k , i, j, k = 1, 2. A particular attention is given to the triple self-coupling of the SM-like Higgs where we found that the one loop corrections can reach 150% is some cases. We also discuss some production mechanisms for h 1 and h 2 at the LHC as well as at the future International Linear Collider. It is found that the production cross section of a pair of SM-like Higgs bosons could be much larger than the corresponding one in the SM and would reveal physics beyond the SM if observable. We also show that in this model the branching ratio of the SM-like Higgs decaying to two singlet scalars could be of the order of 20%, therefore the production of the SM Higgs followed by its decay to a pair of singlets would be an important source of production of singlet scalars.
Natural multi-Higgs model with dark matter and CP violation
Physical Review D - Particles, Fields, Gravitation and Cosmology, 2009
We explore an extension of the Inert Doublet Model which allows also for CP violation in the Higgs sector. This necessitates two non-inert doublets. The lightest neutral scalar of the inert doublet is a candidate for dark matter. Scanning over parameters we preserve the abundance of the dark matter in agreement with the WMAP data. We also impose all relevant collider and theoretical constraints to determine the allowed parameter space for which both the dark matter is appropriate and CP is violated. In addition we find regions where the cutoff of the model originating from naturality arguments can be substantially lifted compared to its Standard Model value, reaching ∼ 2 − 3 TeV.
Journal of Physics: Conference Series, 2010
We consider a Two-Higgs-Doublet Model (2HDM) constrained by the condition that assures cancellation of quadratic divergences up to the leading two-loop order. Regions in the parameter space consistent with existing experimental constraints and with the cancellation condition are determined. The possibility for CP violation in the scalar potential is discussed and regions of tan β − M H ± with substantial amount of CP violation are found. The model allows to ameliorate the little hierarchy problem by lifting the minimal scalar Higgs boson mass and by suppressing the quadratic corrections to scalar masses. The cutoff originating from the naturality arguments is therefore lifted from ∼ 0.6 TeV in the Standard Model to ∼ > 2.5 TeV in the 2HDM, depending on the mass of the lightest scalar.
Journal of High Energy Physics, 2012
We consider a simple extension of the Standard Model by the addition of N real scalar gauge singlets ϕ that are candidates for Dark Matter. By collecting theoretical and experimental constraints we determine the space of allowed parameters of the model. The possibility of ameliorating the little hierarchy problem within the multisinglet model is discussed. The Spergel-Steinhardt solution of the Dark Matter density cusp problem is revisited. It is shown that fitting the recent CRESST-II data for Dark Matter nucleus scattering implies that the standard Higgs boson decays predominantly into pairs of Dark Matter scalars. It that case discovery of the Higgs boson at LHC and Tevatron is impossible. The most likely mass of the dark scalars is in the range 15 GeV < ∼ m ϕ < ∼ 50 GeV with BR(h → ϕ ϕ) up to 96%.
Higgs Dark Matter from a Warped Extra-Dimension – the truncated-inert-doublet model
We construct a 5D Z 2 -symmetric model with three D3-branes: two IR ones with negative tension located at ends of an extra-dimensional interval and one UV-brane with positive tension placed in the middle of the interval. Within this setup we investigate the low-energy effective theory for the bulk SM bosonic sector. The Z 2 -even zero-modes correspond to known standard degrees of freedom, whereas the Z 2 -odd zero modes might serve as dark sector. We discuss two scenarios for spontaneous breaking of the gauge symmetry, one based on expansion of the bulk Higgs field around extra-dimensional vev with non-trivial profile and the second in which the symmetry breaking is triggered by a vev of Kaluza-Klein modes of the bulk Higgs field. It is shown that they lead to the same low-energy effective theory. The effective low-energy scalar sector contains a scalar which mimics the Standard Model (SM) Higgs boson and a second stable scalar particle (dark-Higgs) that is a dark matter candidate; the latter is a component of the zero-mode of Z 2 -odd Higgs doublet. The model that results from the Z 2 -symmetric background geometry resembles the Inert Two Higgs Doublet Model. The effective theory turns out to have an extra residual SU (2)×U (1) global symmetry that is reminiscent of an underlying 5D gauge transformation for odd degrees of freedom. At tree level the SM Higgs and the dark-Higgs have the same mass; however, when leading radiative corrections are taken into account the dark-Higgs turns out to be heavier than the SM Higgs. Implications for dark matter are discussed; it is found that the dark-Higgs can provide only a small fraction of the observed dark matter abundance.
Constraints on and future prospects for Two-Higgs-Doublet Models in light of the LHC Higgs signal
2015
We analyze the Two-Higgs-Doublet Models (2HDMs) of Type I and II for consistency with the latest measurements of the ~125.5 GeV Higgs-like signal at the LHC. To this end, we perform scans of the 2HDM parameter space taking into account all relevant pre-LHC constraints as well as the most recent limits coming from searches for heavy Higgs-like states at the LHC. The current status of the 2HDMs of Type I and II is discussed assuming that the observed 125.5 GeV state is one of the two CP-even Higgs bosons, either the lighter h or the heavier H. Implications for future experiments, including expectations regarding other lighter or heavier Higgs bosons are given. The possible importance of heavier Higgs bosons feeding the signals for the 125.5 GeV state is also evaluated.