Bounds and decays of new heavy vector-like top partners

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The ATLAS and CMS collaborations at the LHC have performed analyses on the existing data sets, studying the case of one vector-like fermion or multiplet coupling to the standard model Yukawa sector. In the near future, with more data available, these experimental collaborations will start to investigate more realistic cases. The presence of more than one extra vector-like multiplet is indeed a common situation in many extensions of the standard model. The interplay of these vector-like multiplet between precision electroweak bounds, flavour and collider phenomenology is a important question in view of establishing bounds or for the discovery of physics beyond the standard model. In this work we study the phenomenological consequences of the presence of two vector-like multiplets. We analyse the constraints on such scenarios from tree-level data and oblique corrections for the case of mixing to each of the SM generations. In the present work, we limit to scenarios with two top-like partners and no mixing in the down-sector.

“…The minimal set of VL multiplets that can mix with SM quarks and a SM (or SM-like) Higgs boson have been extensively studied in literature [23,28,32,[34][35][36]40].…”

Section: Vector-like Multipletsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Interplay of vector-like top partner multiplets in a realistic mixing set-up

Cacciapaglia

Deandrea

Gaur

et al. 2015

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“…Refs. [45][46][47][48] evaluates precision electroweak and flavor constraints on top-partner vector-like quarks, and studies direct LHC signatures.…”

Section: Jhep09(2014)130mentioning

confidence: 99%

Survey of vector-like fermion extensions of the Standard Model and their phenomenological implications

Ellis

Godbole

Gopalakrishna

et al. 2014

111

With the renewed interest in vector-like fermion extensions of the Standard Model, we present here a study of multiple vector-like theories and their phenomenological implications. Our focus is mostly on minimal flavor conserving theories that couple the vector-like fermions to the SM gauge fields and mix only weakly with SM fermions so as to avoid flavor problems. We present calculations for precision electroweak and vector-like state decays, which are needed to investigate compatibility with currently known data. We investigate the impact of vector-like fermions on Higgs boson production and decay, including loop contributions, in a wide variety of vector-like extensions and their parameter spaces.

“…By simply requiring the presence of a Yukawa-type coupling with the standard quarks, the allowed representations can contain both a top and bottom partner (t ′ and b ′ ), but also two exotic quarks with charges + 5 3 (X 5/3 ) and − 4 3 (Y −4/3 ) 1 . In [12] a complete list of the possible representations is presented, including the relevant bounds from precisely measured quantities in the Standard Model (SM). For earlier bounds see for example [13,14].…”

Section: Introductionmentioning

confidence: 99%

Heavy vector-like quark with charge 5/3 at the LHC

Cacciapaglia

Deandrea

Panizzi

et al. 2013

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We study the phenomenology at the Large Hadron Collider of an exotic vectorlike quark with charge +5/3. We relax the assumption of a 100% branching into W t and allow for an arbitrary rate into W plus light quarks, thus covering all possible scenarios. Sizeable decays into light quarks can be achieved, for instance, in a model where the X 5/3 quark is embedded in a doublet with hypercharge 7/6, which also contains a t ′ quark. We study the bounds on the parameter space of this model, and perform a detailed simulation of the X 5/3 pair production and decays. We show that the final state with W tW q, where q = u or c, contributes to the same sign dilepton searches, and that the reach can be improved with alternative cuts optimised on such final state.