Search for the Top Partner at the LHC using Multi-b-Jet Channels

TL;DR

This paper investigates the detection prospects of top partners at the LHC through multi-b-jet channels, focusing on the decay mode $t_p o th$ which is less explored but potentially enhanced by new physics.

Contribution

It introduces a novel search strategy for top partners via multi-b-jet events, emphasizing the importance of the $t_p o th$ decay mode in LHC experiments.

Findings

Multi-b-jet channels provide complementary sensitivity to existing searches.

The $t_p o th$ decay mode can be significantly enhanced by strong dynamics.

Analysis at 8 TeV shows promising detection prospects for top partners.

Abstract

Vector-like quarks are introduced in various new physics models beyond the standard model (SM) at the TeV scale. We especially consider the case that the quark is singlet (triplet) under the SU(2)$_L$ (SU(3)$_c$) gauge group and couples only to the third generation quarks of the SM. The vector-like quark of this kind is often called a top partner. The top partoner $t_p$ decays into $bW, tZ$ and $th$. In the ATLAS and CMS collaborations, the top partner has been searched in the final states of $bW$ and $tZ$, while the search based on the decay mode $t_p\to th$ has not been started yet. However, the decay into $th$ is important since it is significantly enhanced if some strong dynamics exists in the TeV scale. In the presence of a light higgs boson, the decay mode $t_p\to th$ followed by $h\to b\bar{b}$ produces three bottom quarks. We study the sensitivity for the top partner using multi-b-jet events at the 8 TeV run of the LHC experiment. The multi-b-jet eventss turn out to play a complementary role to the existing $t_p\rightarrow bW$ and $tZ$ searches by the ATLAS and CMS collaborations.