Related papers: Have We Observed the Higgs (Imposter)?
The Higgs Triplet Model (HTM) is one of important examples for extended Higgs sectors, because tiny neutrino masses can be simply explained. Unlike the canonical type-I seesaw model, a scale of new particles can be taken as…
The observation of a new particle in the search for the Standard Model (SM) Higgs boson at the LHC, reported by the ATLAS and CMS collaborations, is a milestone in the quest to understand electroweak symmetry breaking. The evidence at the…
We consider present constraints on Two Higgs Doublet Models, both from the LHC at Run 1 and from other sources in order to explore the possibility of constraining a neutral scalar or pseudo-scalar particle lighter than the 125 GeV Higgs…
We present and explore the Higgs physics of a model that in addition to the Standard Model fields includes a lepton number violating singlet scalar field. Based on the fact that the only experimental data we have so far for physics beyond…
In the search for a light Higgs boson, the ATLAS and CMS experiments have observed excesses in both the diphoton ($\gamma\gamma$) and di-tau-pair ($\tau^+\tau^-$) decay channels at about $95$ GeV. The LEP collaboration has also previously…
The analysis of the Higgs boson data by the ATLAS and CMS Collaborations appears to exhibit an excess of h --> gamma\gamma events above the Standard Model (SM) expectations; whereas no significant excess is observed in h --> ZZ* --> {four…
After the observation in 2012 of a new scalar particle closely resembling the Higgs boson of the Standard Model of particle physics, there is a general consensus that there must be Physics Beyond the Standard Model, with present experiments…
In the framework of strongly interacting dynamics for electroweak symmetry breaking, heavy composite particles may arise and cause observable effects, as they should couple strongly to the resulting Higgs boson and affect the signals that…
In many extensions of the standard model, there exist a few extra Higgs bosons. Suppose a heavy neutral Higgs boson H is discovered at the LHC, one could then investigate CP and CPT~ properties of its couplings to a pair of $Z$ bosons…
We investigate the phenomenology of the Standard Model extended by a real gauge-singlet scalar field, focusing on exotic Higgs decay channels. For a light scalar mass in the range \(0 < m_{\phi} < 40\) GeV, the Higgs boson can decay to both…
The usual range of new particle masses, up to a few TeV, searched for at the LHC may be substantially extended if ultraheavy diquark particles exist. A diquark scalar, $S_{uu}$, that interacts perturbatively with two up quarks may be as…
In light of the discovery of a Higgs-like particle at the LHC, we revisit the status of the precision electroweak data, focusing on two discrepant observables: 1) the long-standing 2.4 sigma deviation in the forward-backward asymmetry of…
The discovery made at the Large Hadron Collider (LHC) has revealed that the spontaneous symmetry breaking mechanism is realised in a gauge theory such as the Standard Model (SM) by at least one Higgs doublet. However, the possible existence…
In a number of Higgs-portal models, an $SU(2)$ isospin-singlet scalar boson generically appears at the electroweak scale and can mix with the Standard Model (SM) Higgs boson with a mixing angle $\alpha$. This singlet scalar boson can have…
A search for a new heavy scalar particle $X$ decaying into a Standard Model (SM) Higgs boson and a new singlet scalar particle $S$ is presented. The search uses a proton-proton ($pp$) collision data sample with an integrated luminosity of…
The Real Higgs Triplet model, known as the $\Delta$SM, is a minimal extension of the Standard Model (SM) obtained by adding a hypercharge 0 triplet ($\Delta$). This simple model is motivated by the multi-lepton anomalies and excesses in…
We demonstrate how probes of CP-violating observables in Higgs di-tau decays at prospective future lepton colliders could provide a test of weak scale baryogenesis with significant discovery potential. Measurements at the Circular Electron…
ATLAS and CMS recently show the first results from run 2 of the Large Hadron Collider (LHC) at $\sqrt{s}=13$ TeV. A resonant bump at a mass of around 750 GeV in the diphoton invariant mass spectrum is indicated and the corresponding…
Within models containing a very light scalar particle coupled to the 125 GeV Higgs boson, we present the first detailed study of Higgs decays into three of these light scalars. We determine model-independent conditions which the scalar…
The discovery at the LHC of a scalar particle with properties that are so far consistent with the SM Higgs boson is one of the most important advances in the history of particle physics. The challenge of future collider experiments is to…