Exotic Hadrons with Heavy Flavors -X, Y, Z and Related States-

Understand

In the past decade, exotic hadrons with charm and bottom flavors have been extensively studied both in experiments and in theories.

• In this review, we provide topical discussions by selecting $X,Y,Z$ particles, to which Belle has made important contributions.
• These are $X(3872)$, $Y(4260)$, $Z_c(4430)^+$, $Z_c(3900)^+$, $Z_{b}(10610)^+$ and $Z_{b}(10650)^+$.
• Based on the current experimental observations, we discuss those states with emphasis on hadronic molecule whose dynamics is governed by chiral symmetry and heavy-quark symmetry of QCD.