Novel signatures for vector-like quarks

Abstract

Abstract:We consider supersymmetric extensions of the standard model with a vectorlike doublet (T B) of quarks with charge 2/3 and −1/3, respectively. Compared to nonsupersymmetric models, there is a variety of new decay modes for the vector-like quarks, involving the extra scalars present in supersymmetry. The importance of these new modes, yielding multi-top, multi-bottom and also multi-Higgs signals, is highlighted by the analysis of several benchmark scenarios. We show how the triangles commonly used to represent the branching ratios of the 'standard' decay modes of the vector-like quarks involving W , Z or Higgs bosons can be generalised to include additional channels. We give an example by recasting the limits of a recent heavy quark search for this more general case.

Next-to-leading-order predictions for single vector-like quark production at the LHC

“…Current searches mostly rely on signatures induced by both their pair and single production, although present bounds are mostly driven by the strong pair production mechanism, followed by a decay pattern in which each vector-like quark is assumed to decay into a Standard Model gauge or Higgs boson and a third-generation quark, both legs being potentially decaying differently. Taking into account an integrated luminosity of 35-36 fb −1 , vector-like quarks of about 1.2 TeV are conservatively excluded, regardless of the decay details [6][7][8][9][10], although such a bound can in principle be lowered when exotic decay modes into nonstandard particles exist [11] or if they decay into lighter Standard Model quark generations.…”

Vector-like quarks with non-renormalizable interactions

“…Second, it is possible to consider several vector-like quark multiplets, or other additional particles, like scalars or vector bosons. This may give rise to new production mechanisms [50] or new decay modes [22], in addition to the standard ones described above. Third, one can drop the assumption of renormalizability.…”

“…Experimental data determines an upper limit L exp on the sum of the cross-sections for the production and decay of a pair of heavy quarks, weighted by the efficiency for each decay channel (see ref. [22]):…”

Exotic vectorlike quark phenomenology in the minimal linear σ model

“…Non-standard VLQ top and bottom partner decays into a singlet scalar field like those in Eq. (2) have already been explored in the literature [55][56][57][58][59] (see also [60,61]). These studies mainly consider the singlet scalar σ being invisible at colliders [55,56,62], or decaying into Zγ, γγ final states [58], yet not focusing on the singlet scalar decays from Eq.…”