The inert two-Higgs-doublet model (i2HDM) is a theoretically well-motivated example of minimal consistent dark matter (DM) which provides monojet, mono-$Z$, mono-Higgs, and vector-boson-$\mathrm{fusion}+{\mathbit{E}}_{\mathrm{T}}^{\mathrm{miss}}$ signatures at the LHC, complemented by signals in direct indirect DM search experiments. In this paper we have performed detailed analysis constraints full five-dimensional parameter space i2HDM, coming from perturbativity, unitarity, electroweak...

We obtain tree-level unitarity constraints for the most general Two-Higgs-Doublet Model (2HDM) with explicit $CP$-violation. briefly discuss correspondence between possible violation of limitation and physical content theory.

The Higgs potential of 2HDM keeps its generic form under the group transformation $GL(2,C)$, which is larger than usually considered reparametrization $SU(2)$. This symmetry induces Minkowski space structure in orbit 2HDM. Exploiting this property, we present a geometric analysis number and properties stationary points most general potential. In particular, prove that charge-breaking neutral vacua never coexist establish conditions when explicitly $CP$-conserving has spontaneously...

We continue to explore the consequences of recently discovered Minkowski space structure Higgs potential in two-Higgs-doublet model. Here, we focus on vacuum properties. The search for extrema is reformulated terms 3-quadrics $3+1$-dimensional space. prove that 2HDM cannot have more than two local minima orbit and a twice-degenerate minimum can arise only via spontaneous violation discrete symmetry potential. Investigating topology 3-quadrics, give concise criteria existence noncontractible...

Photons carrying non-zero orbital angular momentum (twisted photons) are well-known in optics. Recently, it was suggested to use Compton backscattering boost optical twisted photons high energies. Twisted electrons the intermediate energy range have also been produced recently. Thus, collisions involving energetic particles seem be feasible and represent a new tool high-energy physics. Here we discuss some generic features of scattering processes initial and/or final state. In order avoid...

The Mott scattering of high-energetic twisted electrons by atoms is investigated within the framework first Born approximation and Dirac's relativistic equation. Special emphasis placed on angular distribution longitudinal polarization scattered electrons. In order to evaluate these properties we consider two experimental setups in which electron beam collides with either a single well-localized atom or macroscopic atomic target. Detailed calculations have been performed for both kinetic...

N-Higgs doublet models (NHDMs) are a popular framework to construct electroweak symmetry breaking mechanisms beyond the standard model. Usually, one builds an NHDM scalar sector which is invariant under certain group. Although several such groups have been used, no general analysis of symmetries possible in exists. Here, we make first step toward this goal by classifying elementary building blocks, namely Abelian groups, with special emphasis on finite groups. We describe strategy that...

An attractive feature of New Physics models with multiple Higgs fields is that they are equipped discrete symmetry groups in the and flavour sectors. These often broken at global minimum potential, either completely or to a proper subgroup, certain phenomenological consequences. Here, we systematically explore these breaking patterns scalar sector three-Higgs-doublet model (3HDM). We use full list allowed 3HDM, for each group find all possible ways it can break by vacuum expectation value...

Within two Higgs doublet models, it is possible that the current vacuum not global minimum, in which case could possibly decay at a later stage. We discuss tree-level conditions must be obeyed by most general scalar potential order to preclude possibility. propose new procedure only more but also easier implement than previously published one, including CP conserving as well violating sectors. illustrate these within context of Z2 model, softly broken complex, parameter.

When building dark matter (DM) models, one often imposes conserved discrete symmetries to stabilize DM candidates. The simplest choice is ${\mathbb Z}_2$ but models with larger stabilizing groups have also been explored. Can a non-abelian group lead viable model? Here, we address this question within the three-Higgs-doublet model based on $\Sigma(36)$, in which stabilization by not only possible inevitable. We show that tight connections between Higgs, fermion, and sectors repeatedly drive...

High-energy photons and other particles carrying nonzero orbital angular momentum (OAM) emerge as a new tool in high-energy physics. Recently, it was suggested to generate with OAM (twisted photons) by the Compton backscattering of twisted optical on relativistic electron beams. Twisted electrons intermediate energy range have also been demonstrated experimentally; protons can, principle, be created similar way. Collisions energetic states can offer look at particle properties interactions....

N-Higgs-doublet models (NHDM) are among the most popular examples of electroweak symmetry breaking mechanisms beyond Standard Model. Discrete symmetries imposed on NHDM scalar potential play a pivotal role in shaping phenomenology model, and various groups have been studied so far. However, spite all efforts, classification finite Higgs-family realizable for any N>2 is still missing. Here, we solve this problem three-Higgs-doublet model by making use Burnside's theorem other results from...

Electromagnetic radiation can be emitted not only by particle charges but also magnetic moments and higher electric multipoles. However, experimental proofs of this fundamental fact are extremely scarce. In particular, the moment contribution has never been observed in any form polarization radiation. Here, we propose to detect it using vortex electrons carrying large orbital angular momentum ℓ. The relative momentum-induced moment, ℓℏω/Ee, becomes much larger than spin-induced ℏω/E...

Models beyond the Standard Model (bSM) often involve elaborate Higgs sectors, which can be a source of CP-violation. It brings up question recognizing in an efficient way whether model is CP-violating. There diffuse belief that issue explicit CP invariance linked to existence basis all coefficients are real; with even theorem proposed decade ago claiming scalar sector any multi-Higgs doublet explicitly CP-conserving if and only its made real by change. This compounded fact specific multi...

A bstract When parametrizing multi-Higgs potentials, it is desirable to express its coefficients via observables. This routinely done for the 2HDM, but this approach often fails in more elaborate models. Here, we show that scalar sector of CP4 3HDM, an intriguing model based on order-4 CP symmetry, can also be parametrized observable-driven manner. The key feature makes work very special tridiagonal form 5 × neutral Higgs mass matrix. We propose a set input observables and present algorithm...

Collision of ultra-intense optical laser and X-ray free electron (XFEL) pulses is a promising approach to detecting nonlinear vacuum polarization (VP), long-standing prediction quantum electrodynamics remaining be tested. Identifying the signals induced by polarized relies on purifying poses significant challenges due strongly reduced signal low signal-to-noise ratio (SNR). Here we propose an that allows one directly detect VP without need for polarizer. We identify new effect in collision...

When building dark matter (DM) models, one often imposes conserved discrete symmetries to stabilize DM candidates. The simplest choice is <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msub><a:mi mathvariant="double-struck">Z</a:mi><a:mn>2</a:mn></a:msub></a:math> but models with larger stabilizing groups have also been explored. Can a non-Abelian group lead viable model? Here, we address this question within the three-Higgs-doublet model based on <d:math...