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 $t\overline{t}+4\tau$, $t\overline{b}\nu +3\tau ,t\overline{t}+4\mu ,t\overline{b}\nu +3\mu$ or $t\overline{t}+4b$. Additional channels ($b\overline{b}+4\tau$, $4t+b\overline{b}$, $6b$, etc) arise in the case of a vectorlike quark of charge −1/3. 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. (letter)