Pentaquarks: review of the experimental evidence

Pentaquarks, namely baryons made of four quarks and one antiquark, have been predicted and searched for since several decades without success. Theoretical and experimental advances in the last two years led to the observation of a number of pentaquark candidates. We review the experimental evidence for pentaquarks as well as their non-observations by some experiments, and discuss to which extent these sometimes contradicting information may lead to a consistent picture.