Tetraquarks — and, by extension,
pentaquarks,
containing five quarks — are considered exotic because they have more than the usual allotment of two or three quarks.
Bound to charm: «Charmonium»
pentaquarks discovered at the Large Hadron Collider in Geneva, Switzerland, might
contain five quarks tightly bound together (as shown) or more loosely bound into a baryon,
containing three quarks, and a meson, consisting of t