In pairticle pheesics, a pion (short for pi meson, denotit wi π) is ony o three subatomic pairticles: π0, π+, an π−. Each pion consists o a quark an an antiquark an is tharefore a meson. Pions are the lichtest mesons an thay play an important role in explainin the law-energy properties o the strang nuclear force.
Pions are unstable, wi the charged pions π+ an π− decayin wi a mean life time o 26 nanoseconds an the neutral pion π0 decayin wi an even shorter lifetime. Charged pions tend tae decay intae muons an muon neutrinos, an neutral pions intae gamma rays.
Pions are nae produced in radioactive decay, but are produced commonly in heich energy accelerators in collisions atween hadrons. Aw types o pions are an aa produced in naitural processes when heich energy cosmic ray protons an ither hadronic cosmic ray components interact wi matter in the Yird's atmosphere. Recently, detection o characteristic gamma rays oreeginatin frae decay o neutral pions in twa supernova remant starns haes shawn that pions are produced copiously in supernovas, maist probably in conjunction wi production o heich energy protons that are detectit on Yird as cosmic rays.