Since all quarks have a spin of 1/2, all baryons have a spin of 1/2 or 3/2 (the spins can cancel out). 1/2 spin baryons have the lowest energy state. 3/2 spin baryons are extremely unstable, and only live for 10 seconds. After that, they jump down to a lower energy state by releasing photons containing energy. These 3/2 spin baryons are known as higher energy resonances.