Lepton collider indirect signatures of dark CP-violation (original) (raw)

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.

CP violation and BSM Higgs bosons

Proceedings of Prospects for Charged Higgs Discovery at Colliders — PoS(CHARGED2016)

We study extensions of the Standard Model (SM) in which copies of the SM scalar SU(2) doublet are added to the Higgs sector. These scalar doublets either acquire a Vacuum Expectation Value (VEV) and hence are active or do not develop a VEV and are inert. We consider CP-violation (CPV) in both the active and inert sector. As an example of a model with CPV in the active sector, we present a Type-I 2-Higgs-Doublet Model (2HDM) with two active doublets and show Large Hadron Collider (LHC) signals of such a scenario. The amount of CPV in this case is very limited due to constraints coming from Electric Dipole Moment experiments. Moreover, 2HDMs with only active doublets do not provide a Dark Matter (DM) candidate. As a result, we turn to 3-Higgs-Doublet Models (3HDMs) where unbounded CPV and viable DM candidates could be introduced simultaneously in the inert sector. We investigate DM phenomenology of such models.

CP violating Two-Higgs-Doublet Model: constraints and LHC predictions

Journal of High Energy Physics

Two-Higgs-Doublet Models (2HDMs) are amongst the simplest extensions of the Standard Model. Such models allow for tree-level CP Violation (CPV) in the Higgs sector. We analyse a class of CPV 2HDM (of Type-I) in which only one of the two Higgs doublets couples to quarks and leptons, avoiding dangerous Flavour Changing Neutral Currents. We provide an up to date and comprehensive analysis of the constraints and Large Hadron Collider (LHC) predictions of such a model. Of immediate interest to the LHC Run 2 is the golden channel where all three neutral Higgs bosons are observed to decay into gauge boson pairs, W W and ZZ, providing a smoking gun signature of the CPV 2HDM.

Exploring collider signatures of the inert Higgs doublet model

We revisit the multilepton (ml) + E / T signatures of the Inert Doublet Model of dark matter in future LHC experiments for m = 3,4 and simulate, for the first time, the m = 5 case. In addition to the usual constraints like unitarity, perturbativity, the precision electroweak data, the observed dark matter relic density of the Universe, we take into account the stringent constraints from the post Higgs (h) discovery era like the measured M h and the upper bound on the width of h decay which were not included in the earlier analyses. We find that the IDM model embedded in a grand dessert scenario so that the unitarity constraint holds up to a very high scale, the entire parameter space allowed by the above constraints can be probed by the LHC via the 3l for an integrated luminosity ∼ 3000 fb −1. On the other hand if any new physics shows up at a scale ∼ 10 TeV only a part of the enlarged allowed parameter space can be probed. The 4l and 5l signals can help to discriminate among different IDM scenarios as and when sufficient integrated luminosity accumulates.

Measuring CP violation in two-Higgs-doublet models in light of the LHC Higgs data

Journal of High Energy Physics, 2014

In Two-Higgs-Doublet models, the conditions for CP violation can be expressed in terms of invariants under U(2) rotations among the two SU(2) Higgs doublet fields. In order to design a strategy for measuring the invariants we express them in terms of observables, i.e., masses and couplings of scalar bosons. We find amplitudes directly sensitive to the invariants. Observation of the Standard-Model-like Higgs boson at the LHC severely constrains the models. In particular, in the model with Z 2 symmetry imposed on dimension-4 terms (in order to eliminate tree-level flavour-changing neutral currents), CP violation is strongly suppressed. On the other hand, the most general Two-Higgs-Doublet model (without Z 2 symmetry) is compatible with the LHC data, and would still allow for CP violation to be present in the model. Consequently, also flavour-changing neutral currents would in general be expected. We briefly sketch a strategy for measuring the remaining CP violation.

CP violating scalar Dark Matter

Journal of High Energy Physics

We study an extension of the Standard Model (SM) in which two copies of the SM scalar SU(2) doublet which do not acquire a Vacuum Expectation Value (VEV), and hence are inert, are added to the scalar sector. We allow for CP-violation in the inert sector, where the lightest inert state is protected from decaying to SM particles through the conservation of a Z 2 symmetry. The lightest neutral particle from the inert sector, which has a mixed CP-charge due to CP-violation, is hence a Dark Matter (DM) candidate. We discuss the new regions of DM relic density opened up by CP-violation, and compare our results to the CP-conserving limit and the Inert Doublet Model (IDM). We constrain the parameter space of the CP-violating model using recent results from the Large Hadron Collider (LHC) and DM direct and indirect detection experiments.

Pseudo-Goldstone dark matter model with CP violation

Journal of High Energy Physics

We consider an explicitly CP-violating model with two Higgs doublets and one complex singlet scalar. The singlet S is charged under a global U(1) symmetry which is softly broken by a mass term μ2S2 + H.c.. Imaginary part of S is a stable dark matter candidate which at the tree level, in the limit of zero momentum transfer, decouples from nucleons naturally satisfying all existing direct detection limits on dark matter scattering cross-section. It is explicitly shown that within this framework in the alignment limit CP violation is still present in contrast to a popular version of a 2-Higgs doublet model with softly broken Z2 symmetry. In this context, we investigate dark matter implications of the model both with and without CP violation in the scalar sector. In particular, dark matter relic abundance is calculated and the possibility for its indirect detection is discussed.

Exploring the CP-violating Inert-Doublet Model

Journal of High Energy Physics, 2011

We have explored properties of an extension of the Inert Doublet Model by the addition of an extra non-inert scalar doublet. The model offers a possibility of CP violation in the scalar sector and a candidate for the Dark Matter. Allowed regions in the plane spanned by the mass of the Dark-Matter particle and the lightest neutral Higgs particle have been identified, and constraints from direct-detection experiments have been studied. For favorable parameter regions one may observe long-lived charged particles produced at the LHC.