## What is/are Scalar Singlet?

Scalar Singlet - We find that the minimal framework compatible with the neutrino option requires the Standard Model to be extended by two real scalar singlet fields in addition to right-handed neutrinos.^{[1]}As other gains, the scalar content required by the implementation of the mechanism provides contribution to rare lepton decays, may accommodate the $g-2$ of the muon and poses a scalar singlet that may drive inflation through Higgs inflation mechanism without problem with loss of unitarity.

^{[2]}Global fits with GAMBIT have been carried out on a variety of models including supersymmetric models, scalar singlet dark matter, fermionic and vector Higgs portal dark matter and axions.

^{[3]}We assume a heavy SUSY spectrum with multi-TeV squarks and SU(2) scalar singlets as well as the decoupling limit in the SUSY Higgs sector.

^{[4]}Namely, we consider models containing a new (leptophobic) neutral gauge boson Zt and two scalar singlets, plus extra matter required to cancel the U(1)t anomalies.

^{[5]}Our prediction of WIMP DM relic density in each model is due to a $\sim$ TeV mass matter-parity odd real scalar singlet ($\subset {16}_H \subset$ SO(10)) verifiable by LUX and XENON1T experiments.

^{[6]}Scalar singlet dark matter in anomaly-free composite Higgs models is accompanied by exotic particles to which the dark matter annihilates.

^{[7]}We perform a global fit within the pseudo-Nambu-Goldstone Dark Matter (DM) model emerging from an additional complex scalar singlet with a softly broken global U (1) symmetry.

^{[8]}The latter feature follows from an underlying unconventional CP symmetry of order 4 imposed in the sectors beyond the SM composed of only two vector-like quarks of charge −1/3 and one complex scalar singlet.

^{[9]}We study the one-loop corrections to the $Zb\bar{b}$ vertex in extensions of the Standard Model with arbitrary numbers of scalar doublets, neutral scalar singlets, and charged scalar singlets.

^{[10]}We then specialize to the $O(2)$ model and extract rigorous bounds on the three-point function coefficient of two currents and the unique relevant scalar singlet, as well as those of two currents and the stress tensor.

^{[11]}We investigate the prospective reach of the 14 TeV HL-LHC for resonant production of a heavy Higgs boson that decays to two SM-like Higgs bosons in the $4b$ final state in the scalar singlet extended Standard Model.

^{[12]}Our most general conformally invariant scalar potential generates the electroweak symmetry breaking via the Coleman-Weinberg mechanism, and the new scalar singlet acquires its mass through radiative corrections of the SM particles and the scalar dark matter.

^{[13]}Upcoming PBHs searches have in particular the potential to rule out almost the entire parameter space of popular theories such as the minimal supersymmetric standard model and scalar singlet Dark Matter.

^{[14]}Our analysis shows that the low mass dark matter regime (Mρ1$$ {M}_{\rho_1} $$ ≲ 60 GeV) is still allowed by the experiments like XENON1T, LHC (via Higgs invisible branching) and Fermi-LAT, making the dark matter phenomenology drastically different from the standard Inert Doublet and the Scalar Singlet models.

^{[15]}We show how the spontaneous breaking of the Peccei-Quinn symmetry by a scalar singlet can provide us with solutions not only to the strong CP and dark matter problems but can also help to generate naturally suppressed off-diagonal CKM elements and small neutrino masses via the inverse seesaw mechanism.

^{[16]}We propose a multiscalar singlet extension of the singlet-triplet Higgs model capable of explaining the SM fermion mass spectrum and mixing parameters.

^{[17]}A recent study [1] has shown that a simplified model predicting a heavy scalar of mass 270 GeV ($H$) that decays to a Standard Model (SM) Higgs boson in association with a scalar singlet of mass 150 GeV ($S$) can accommodate several anomalous multi-lepton results in proton-proton collisions at the Large Hadron Collider (LHC).

^{[18]}This additional scalar singlet mixes with SM Higgs and on diagonalisation of the mass matrix two CP even scalar eigenstates are obtained one of which is attributed to the physical Higgs (with mass 125.

^{[19]}We assume that lepton number is broken dynamically due to a lepton number carrier scalar singlet which acquires a non-zero vacuum expectation value.

^{[20]}It can feature a large visible Higgs sector in the broken phase, behave like a 2HDM with scalar singlet dark matter in the dark singlet phase, or, in the inert doublet phase, extend an inert doublet model by mixing a singlet with the SM Higgs boson.

^{[21]}In particular, we consider the singlet-like heavy mass eigenstate of a mixed two Higgs doublet and scalar singlet model in the $U(1)_{B-L}$ extension of the Standard Model.

^{[22]}In such models, a two-step phase transition can be obtained with the scalar singlet acquiring a vacuum expectation value at intermediate temperatures.

^{[23]}Author(s): Altmannshofer, Wolfgang; Maddock, Brian; Profumo, Stefano | : We consider a framework where the Standard Model is augmented by a second SU(2) scalar doublet and by a real scalar singlet that, protected by a Z2 symmetry, provides a particle Dark Matter candidate.

^{[24]}We also show a physics application of BubbleProfiler in the scalar singlet extension of the Standard Model of particle physics by calculating the action as a function of model parameters during the electroweak phase transition.

^{[25]}A bstractWe reconsider complex scalar singlet dark matter stabilised by a ℤ3 symmetry.

^{[26]}We introduce $U(1)_X$ gauge symmetry with a new charge $X$ in the dark sector in order to stabilize the mass of the scalar singlet with a new gauge boson.

^{[27]}Such signatures are predicted in a number of extensions of the standard model (SM), including next-to-minimal supersymmetry and two-Higgs-doublet models with an additional scalar singlet.

^{[28]}We illustrate a simple two component DM model, consisting of one inert SU(2) L scalar doublet and a scalar singlet, both stabilised by additional Z 2 × Z 2 ′ $$ {\mathcal{Z}}_2\times {\mathcal{Z}}_2^{\prime } $$ symmetry, which also aid to vacuum stability.

^{[29]}Meanwhile, the gauged $U(1)_{L_\mu-L_\tau}$ symmetry is broken spontaneously by the scalar singlet $S$, resulting to the massive gauge boson $Z'$.

^{[30]}This work investigates a simple, representative extension of the Standard Model with a real scalar singlet and spontaneous $Z_2$ breaking, which allows for a strongly first-order phase transition, as required by electroweak baryogenesis.

^{[31]}We study both the CP-even and CP-odd effective chiral Lagrangians of next minimal composite Higgs model {with symmetry breaking pattern depicted by the coset $SO(6)/SO(5)$} through the sigma/omega decomposition, in which the Goldstone matrix of the coset is decomposed in terms of the standard model Higgs doublet and an additional scalar singlet $s$ at the electroweak scale.

^{[32]}We consider both freeze-out and freeze-in mechanisms for producing the observed DM abundance in a model where the DM consists of scalar singlet particles coupled to the Standard Model sector via the Higgs portal.

^{[33]}Focusing on two simplified scenarios, an higgsed U(1) and a two scalar singlet model, we show the impact of friction effects acting on the bubble walls on the gravitational wave spectra and on the consequences for present and future interferometer experiments.

^{[34]}Similarly to other versions, the theory consists of a Two-Higgs-Doublet Model plus a scalar singlet embedded into the SM ⊗ U (1)X gauge group, and introduces small modifications to the Z -boson interactions.

^{[35]}

## Real Scalar Singlet

We find that the minimal framework compatible with the neutrino option requires the Standard Model to be extended by two real scalar singlet fields in addition to right-handed neutrinos.^{[1]}Our prediction of WIMP DM relic density in each model is due to a $\sim$ TeV mass matter-parity odd real scalar singlet ($\subset {16}_H \subset$ SO(10)) verifiable by LUX and XENON1T experiments.

^{[2]}Author(s): Altmannshofer, Wolfgang; Maddock, Brian; Profumo, Stefano | : We consider a framework where the Standard Model is augmented by a second SU(2) scalar doublet and by a real scalar singlet that, protected by a Z2 symmetry, provides a particle Dark Matter candidate.

^{[3]}This work investigates a simple, representative extension of the Standard Model with a real scalar singlet and spontaneous $Z_2$ breaking, which allows for a strongly first-order phase transition, as required by electroweak baryogenesis.

^{[4]}

## Complex Scalar Singlet

We perform a global fit within the pseudo-Nambu-Goldstone Dark Matter (DM) model emerging from an additional complex scalar singlet with a softly broken global U (1) symmetry.^{[1]}The latter feature follows from an underlying unconventional CP symmetry of order 4 imposed in the sectors beyond the SM composed of only two vector-like quarks of charge −1/3 and one complex scalar singlet.

^{[2]}A bstractWe reconsider complex scalar singlet dark matter stabilised by a ℤ3 symmetry.

^{[3]}

## Additional Scalar Singlet

This additional scalar singlet mixes with SM Higgs and on diagonalisation of the mass matrix two CP even scalar eigenstates are obtained one of which is attributed to the physical Higgs (with mass 125.^{[1]}Such signatures are predicted in a number of extensions of the standard model (SM), including next-to-minimal supersymmetry and two-Higgs-doublet models with an additional scalar singlet.

^{[2]}We study both the CP-even and CP-odd effective chiral Lagrangians of next minimal composite Higgs model {with symmetry breaking pattern depicted by the coset $SO(6)/SO(5)$} through the sigma/omega decomposition, in which the Goldstone matrix of the coset is decomposed in terms of the standard model Higgs doublet and an additional scalar singlet $s$ at the electroweak scale.

^{[3]}

## Two Scalar Singlet

Namely, we consider models containing a new (leptophobic) neutral gauge boson Zt and two scalar singlets, plus extra matter required to cancel the U(1)t anomalies.^{[1]}Focusing on two simplified scenarios, an higgsed U(1) and a two scalar singlet model, we show the impact of friction effects acting on the bubble walls on the gravitational wave spectra and on the consequences for present and future interferometer experiments.

^{[2]}

## scalar singlet dark

Global fits with GAMBIT have been carried out on a variety of models including supersymmetric models, scalar singlet dark matter, fermionic and vector Higgs portal dark matter and axions.^{[1]}Scalar singlet dark matter in anomaly-free composite Higgs models is accompanied by exotic particles to which the dark matter annihilates.

^{[2]}Upcoming PBHs searches have in particular the potential to rule out almost the entire parameter space of popular theories such as the minimal supersymmetric standard model and scalar singlet Dark Matter.

^{[3]}It can feature a large visible Higgs sector in the broken phase, behave like a 2HDM with scalar singlet dark matter in the dark singlet phase, or, in the inert doublet phase, extend an inert doublet model by mixing a singlet with the SM Higgs boson.

^{[4]}A bstractWe reconsider complex scalar singlet dark matter stabilised by a ℤ3 symmetry.

^{[5]}

## scalar singlet model

Our analysis shows that the low mass dark matter regime (Mρ1$$ {M}_{\rho_1} $$ ≲ 60 GeV) is still allowed by the experiments like XENON1T, LHC (via Higgs invisible branching) and Fermi-LAT, making the dark matter phenomenology drastically different from the standard Inert Doublet and the Scalar Singlet models.^{[1]}In particular, we consider the singlet-like heavy mass eigenstate of a mixed two Higgs doublet and scalar singlet model in the $U(1)_{B-L}$ extension of the Standard Model.

^{[2]}Focusing on two simplified scenarios, an higgsed U(1) and a two scalar singlet model, we show the impact of friction effects acting on the bubble walls on the gravitational wave spectra and on the consequences for present and future interferometer experiments.

^{[3]}

## scalar singlet extension

We propose a multiscalar singlet extension of the singlet-triplet Higgs model capable of explaining the SM fermion mass spectrum and mixing parameters.^{[1]}We also show a physics application of BubbleProfiler in the scalar singlet extension of the Standard Model of particle physics by calculating the action as a function of model parameters during the electroweak phase transition.

^{[2]}