Exotic Signals of Vectorlike Quarks

Vectorlike fermions are an important target for hadron collider searches. We show that the vectorlike quarks may predominantly decay via higher-dimensional operators into a quark plus a couple of other Standard Model fermions. Pair production of vectorlike quarks of charge 2/3 at the LHC would then lead to a variety of possible final states, including $t\bar{t}+4\tau$, $t\bar b\nu + 3\tau$,$t\bar t + 4\mu$,$t\bar b\nu + 3\mu$or$t\bar t + 4b$. Additional channels ($b\bar{b}+4\tau$, $6b$, etc.) arise in the case of a vectorlike quark of charge $-1\mathrm{/}3$. If the vectorlike quark decays into three light quarks, then the $(3j)(3j)$ signal is more difficult to observe, and the vectorlike quark mass is almost unconstrained by current searches.