Overview on pentaquarks

An overview of the exotic pentaquark states is provided, from early searches in $KN$ scattering experiments in the 1970’s to the now-debunked $\Theta^+(1540)$ in the early 2000’s, to the discovery two resonances consistent with pentaquark states by LHCb in 2015. We review the full angular analysis of $\Lambda^0_b \to J/ \psi K^-p$ that led to affirmation of the resonant nature of the $P^+_c (4450)$ and $P^+_c (4380)$ pentaquark candidates. We summarize the latest results, ongoing work and future prospects for other pentaquark searches at LHCb.