Related papers: Hunting for Vectorlike Quarks
We consider multi-Higgs-doublet models which, for symmetry reasons, have a universal Higgs-Yukawa (HY) coupling, $g$. This is identified with the top quark $g=g_t\approx 1$. The models are concordant with the quasi-infrared fixed point, and…
A search for the production of a Higgs boson in association with a single top quark (tH) is performed using the decay $\text{H} \to \text{b}\bar{\text{b}}$. This Higgs boson production mode is sensitive to the coupling modifiers of the…
A search is performed for Higgs bosons produced in association with top quarks using the diphoton decay mode of the Higgs boson. Selection requirements are optimized separately for leptonic and fully hadronic final states from the top quark…
This paper presents a search for Higgs bosons decaying to four leptons, either electrons or muons, via one or two light exotic gauge bosons $Z_d$, $H\to Z Z_d \to 4\ell$ or $H\to Z_d Z_d \to 4\ell$. The search was performed using $pp$…
We study the phenomenology of charged Higgs bosons ($H^\pm$) and Vector-Like Quarks (VLQs), denoted as $T$, the latter possessing a charge identical to the top quark one, within the framework of the Two Higgs Doublet Model Type-II…
A search for a pseudoscalar $a$ produced in association with a top-quark pair, or in association with a single top quark plus a $W$ boson, with the pseudoscalar decaying into $b$-quarks ($a\rightarrow b\bar{b}$), is performed using the full…
We analyze the advantages of a linear-collider program for testing a recent theoretical proposal where the Higgs-boson Yukawa couplings are radiatively generated, keeping unchanged the standard-model mechanism for electroweak-gauge-symmetry…
We show that the branching ratio R_{b/tau}=BR(h^0->bb)/BR(h^0->tau tau) of the Higgs boson h^0 may usefully differentiate between the Higgs sectors of the Minimal Supersymmetric Standard Model (MSSM) and non-supersymmetric models such as…
In the CMSSM the heaviest scalar and pseudo-scalar Higgs bosons decay largely into b-quarks and tau-leptons because of the large $\tan\beta$ values favored by the relic density. In the NMSSM the number of possible decay modes is much…
A search is presented for a heavy vector resonance decaying into a Z boson and the standard model Higgs boson, where the Z boson is identified through its leptonic decays to electrons, muons, or neutrinos, and the Higgs boson is identified…
The presence of a new singlet scalar particle a can open up new decay channels for the Higgs boson, through cascades of the form h -> 2a -> X, possibly making discovery through standard model channels impossible. If a is CP-odd, its decay…
Top quark production offers the unique opportunity to search for a charged Higgs boson ($H^\pm$), as the contribution from $t\to H^+b\to \tau^+\nu b$ can be large in extensions of the Standard Model. We use results from a search for top…
We perform a detailed study of the decays of the lighter top and bottom squarks (t~_1 and b~_1) in the Minimal Supersymmetric Standard Model (MSSM). We show that the decays into Higgs or gauge bosons, i.e. t~_1 -> b~_1 + (H^+ or W^+) and…
A search for the standard model Higgs boson is performed in a data sample corresponding to an integrated luminosity of 1.1 fb$^{-1}$, recorded by the CMS detector in proton-proton collisions at the LHC with a 7 TeV center-of-mass energy.…
A direct search for the standard model Higgs boson, H, produced in association with a vector boson, V (W or Z), and decaying to a charm quark pair is presented. The search uses a data set of proton-proton collisions corresponding to an…
A search for exotic decays of the Higgs boson $H$ into new scalar or pseudoscalar particles that subsequently decay into $b$-quarks is presented. The search considers $ZH$ production with several decay scenarios for the Higgs boson: first…
Extensions of the Standard Model that include vector-like quarks commonly also include additional particles that may mediate new production or decay modes. Using as example the minimal linear $\sigma$ model, that reduces to the minimal…
A search is presented for the pair production of heavy vector-like $B$ quarks, primarily targeting $B$ quark decays into a $W$ boson and a top quark. The search is based on $36.1$ $fb^{-1}$ of $pp$ collisions at $\sqrt{s}$ = 13 TeV recorded…
After many years of searches, the Higgs boson was observed by the ATLAS and CMS collaborations in July 2012. Since then, its properties have been measured using primarily the bosonic decay channels: $H \to \gamma\gamma $, $H \to Z Z$, $H…
Vector-like fermions charged under both the Standard Model and a new dark gauge group arise in many theories of new physics. If these fermions include an electroweak doublet and singlet with equal dark charges, they can potentially connect…