Abstract

Since invention of quark model for hadrons by Gell-Mann particle physics tries to understand why experimentally we see only mesons composed of a quark-antiquark pair or baryons composed of three quarks. Over the years, many candidates for hadrons composed of more quarks or other exotic candidates were observed, but the question whether they are indeed exotic proved difficult to answer. In my talk I will focus on one particular candidate, namely Z(4430)+, and will describe details of the experimental evidence we have for it. It will be shown, that the Z(4430)+ cannot be conventional state composed of quark-antiquark and that it indeed has to be exotic. With the Z(4430)+ established as exotic state, hadron spectroscopy is at start of new era with even more questions opened.