Positron

Positron (antielectron)

Cloud chamber photograph by C. D. Anderson of the first positron ever identified. A 6 mm lead plate separates the chamber. The deflection and direction of the particle's ion trail indicate that the particle is a positron.
Composition	Elementary particle
Statistics	Fermionic
Generation	First
Interactions	Gravity, electromagnetic, weak
Symbol	e+ , β+
Antiparticle	Electron
Theorized	Paul Dirac (1928)
Discovered	Carl D. Anderson (1932)
Mass	me 9.1093837139(28)×10−31 kg[1] 5.485799090441(97)×10−4 Da[2] 0.51099895069(16) MeV/c2[3]
Mean lifetime	stable (same as electron)
Electric charge	+1 e +1.602176634×10−19 C[4]
Spin	1/2 ħ (same as electron)
Weak isospin	LH: 0, RH: 1/2

The positron or antielectron is the particle with an electric charge of +1e, a spin of 1/2 (the same as the electron), and the same mass as an electron. It is the antiparticle (antimatter counterpart) of the electron. When a positron collides with an electron, annihilation occurs. If this collision occurs at low energies, it results in the production of two or more photons.

Positrons can be created by positron emission radioactive decay (through weak interactions), or by pair production from a sufficiently energetic photon which is interacting with an atom in a material.