Search for vector-like quarks and excited quarks at CMS

We present the results of the latest searches for new hypothetical heavy quarks using proton-proton collisions data collected with the CMS detector at the CERN LHC at a center-of-mass energy of 13 TeV. Vector-like quarks are postulated to solve the hierarchy problem and stabilize the Higgs mass and they are not constrained by the Higgs discovery and electroweak measurements, as for the case of a fourth generation of fermions. They can either be produced singly or pair-wise and their decays result in a variety of final states, containing massive standard model quarks and bosons (Z, W, H). Being these new particles expected to be appearing at the TeV scale, they give rise to boosted topologies, in which jet substructures techniques play a fundamental role. An alternative type of heavy quark resonance are the excited quarks, which are predicted by the compositeness model, being their evidence a clear signature of the composite structure of the ordinary matter. Their decay leads to the corresponding ordinary quark and a gluon, but also radiative transitions and decay in electroweak bosons are possible. The search for these new particles relies on the identification of an eventual excess of data on top of steeply falling background; therefore an optimal control of the backgrounds is fundamental.Exclusions limits are set on the production cross sections for vector-like and excited quarks, considering several final signatures and multiple theoretical benchmarks.