Objects made of 4 quarks and one anti-quark called pentaquarks. Pentaquarks can reveal themselves as a compact multiquark states – “genuine pentaquarks” or as a meson-baryon molecule. In the latter case the meson and baryon form a bound/quasi-bound system utilizing long-range meson exchange (pi, eta, rho, omega). Objects with the same quantum numbers are allowed to mix, therefore pentaquarks can spend some fraction of time is a form of multiquark and also as a meson-baryon molecule or even a baryon.


Meson-Baryon molecule