Discovering the top partners at the LHC using same-sign dilepton final states

By Roberto Contino, G. Servant. 2008

220 citations recorded by the source corpus.

A natural, non-supersymmetric solution to the hierarchy problem generically requires fermionic partners of the top quark with masses not much heavier than 500GeV. We study the pair production and detection at the LHC of the top partners with electric charge Qe = 5/3 (T5/3) and Qe = −1/3 (B), that are predicted in models where the Higgs is a pseudo-Goldstone boson. The exotic T 5/3 fermion, in particular, is the distinct prediction of a LR custodial parity invariance of the electroweak symmetry breaking sector. Both kinds of new fermions decay to W t, leading to a tW final state. We focus on the golden channel with two same-sign leptons, and show that a discovery could come with less than 100pb −1 (less than 20fb −1 ) of integrated luminosity for masses M = 500GeV (M = 1TeV). In the case of the T5/3, we present a simple strategy for its reconstruction in the fully hadronic decay chain. Although no full mass reconstruction is possible for the B, we still find that the same-sign dilepton channel offers the best chances of discovery compared to other previous searches that used final states with one or two opposite-sign leptons, and hence suffered from the large tbackground.

Subfields: Artificial Intelligence, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/1c9d8a083e37865e45d8170a8892efd0e1e5c035

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Citations in the corpus

A first top partner hunter’s guide (2012, background): “for in the first thorough work on simplified top partner models [21] and in the following studies (see in particular [22, 28]).”
Non-resonant new physics in top pair production at hadron colliders (2010, background): “J H E P 0 3 ( 2 0 1 1 ) 1 2 5 Finally, note that a generic prediction of recent models of Higgs and top compositeness is the existence of fermionic top partners (“custodians”) whose mass is below the mass scale of the vector resonances mρ [48–50].”
Electroweak and QCD corrections to top-pair hadroproduction in association with heavy bosons (2015, background): “same-sign di-leptons or tri-leptons final states), including SUSY [1–3], extra dimensions [4], and models with heavy top-quark partners [5].”
Flavor and CP invariant composite Higgs models (2011, background): “Fermionic resonances can be singly [34] or doubly produced [35].”