# Exotic decays of top partners with charge 5/3: bounds and opportunities

## TL;DR

This paper investigates exotic decay modes of charge-5/3 top partners in composite Higgs models, showing current experimental bounds and highlighting potential for future searches involving photons and top-rich final states.

## Contribution

It identifies new decay channels of top partners and analyzes their experimental constraints, proposing novel signatures for future collider searches.

## Key findings

- Existing same-sign lepton searches constrain exotic decays.
- New decay channels include color-sextet and scalar states.
- Opportunities for improved detection via photons and top-rich final states.

## Abstract

Exotic decays of top partners in new bosons are the norm in realistic models of a composite Higgs. We focus on the custodial charge-$5/3$ partner, which normally decays exclusively into $tW^+$. The new channels include a colour-sextet, $X_{5/3} \to \bar{b} \pi_6$, as well as singly and doubly charged scalars, $X_{5/3} \to t \phi^+$, $b \phi^{++}$. We use existing same-sign lepton searches to show that the new final states are constrained at the same level as the standard one. At the same time, exotic final states also offer opportunities for improvement: examples include a hard photon in $X_{5/3}\rightarrow t\phi^+\rightarrow tW^+\gamma$ decays, and top-rich channels which arise in several exotic $X_{5/3}$ decays.