Related papers: Detecting Fourth Generation Quarks at Hadron Colli…
We study the implications of a large degree of compositeness for the light generation quarks in composite pseudo-Nambu-Goldstone-boson Higgs models. We focus in particular on viable scenarios where the right-handed up-type quarks have a…
We pursue a scenario where the lighter top squark (stop) mass is accessible for the Large Hadron Collider (LHC) in the near future, while gluinos and first two generation squarks are heavier. At $\sqrt{s} = 8$ TeV, we investigate the…
This paper presents a search for a new heavy particle produced in association with a top or antitop quark. Two models in which the new heavy particle is a color singlet or a color triplet are considered, decaying respectively to tbarq or…
The associated production of $Z$ boson and a pair of new quarks at the Large Hadron Collider (LHC) is studied. The cross sections for both sequential fermions and vector-like fermions are presented. It is found that for sequential fermions…
We present a search for pair production of a fourth generation t' quark and its antiparticle, followed by their decays to a W boson and a jet, based on an integrated luminosity of 5.3/fb of proton-antiproton collisions at sqrt{s}=1.96 TeV…
We point out that events with 6 or more top quarks may be observed at the LHC if certain particles exist at the TeV scale. In a model where a vectorlike quark of charge 2/3 decays into a top quark and a pseudoscalar particle, which…
The results of a search for the pair production of a fourth-generation up-type quark (t') in proton-proton collisions at sqrt(s) = 7 TeV are presented, using data corresponding to an integrated luminosity of about 5.0 inverse femtobarns…
We study the single production of the fourth family quarks through the process pp--> Q'jX at the Large Hadron Collider (LHC). We have calculated the decay widths and branching ratios of the fourth family quarks (b' and t') in the mass range…
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…
Metastable quarks of 4th generation are predicted in the framework of heterotic string phenomenology. Their presence in heavy stable hadrons are usually strongly constrained; however their hidden compositions in Heavy doubly charged baryons…
The LHC, with its seven-fold increase in energy over the Tevatron, is capable of probing regions of SUSY parameter space exhibiting qualitatively new collider phenomenology. Here we investigate one such region in which first generation…
A general search for the pair production of resonances, each decaying to two quarks, is reported. The search is conducted separately for heavier resonances (masses above 400 GeV), where each of the four final-state quarks generates a…
Vectorlike fermions are an important target for hadron collider searches. We show that the vectorlike quarks may predominantly decay via higher-dimensional operators into a quark plus a couple of other Standard Model fermions. Pair…
A search is performed for a vector-like heavy T quark that is produced in pairs and that decays to a top quark and a Higgs boson. The data analysed correspond to an integrated luminosity of 19.7 inverse femtobarns collected with the CMS…
A search for the production of a heavy B quark, having electric charge -1/3 and vector couplings to W, Z, and H bosons, is carried out using proton-proton collision data recorded at the CERN LHC by the CMS experiment, corresponding to an…
The pair production of heavy fourth-generation quarks, which are predicted under the hypothesis of flavor democracy, is studied using tree-level Monte Carlo generators and fast detector simulation. Two heavy-quark mass values, 500 and…
A search for pair production of massive vector-like T and B quarks in proton-proton collisions at sqrt(s) = 13 TeV is presented. The data set was collected in 2015 by the CMS experiment at the LHC and corresponds to an integrated luminosity…
A measurement of the jet mass distribution in hadronic decays of Lorentz-boosted top quarks is presented. The measurement is performed in the lepton+jets channel of top quark pair production ($\mathrm{t\bar{t}}$) events, where the lepton is…
We determine the masses of the sequential fourth generation quarks $b'$ and $t'$ in the extension of the Standard Model by solving the dispersion relations associated with the mixing between the neutral states $Q\bar q$ and $\bar Qq$, $Q$…
We analyse the impact of LHC and Tevatron Higgs data on the viability of the Standard Model with a sequential fourth generation (SM4), assuming Dirac neutrinos and a Higgs mass of 125 GeV. To this end we perform a combined fit to the signal…