What quantities are conserved in pair production?

(c) Energy and momentum are conserved during pair production. State two other quantities that must also be conserved. Any two of: charge, lepton number, baryon number or strangeness.

What are particle antiparticle pairs?

For each particle of matter there exists an equivalent particle with opposite quantum characteristics, called an antiparticle. Particle and antiparticle pairs are created by large accumulations of energy. This is a manifestation of Einstein’s famous equivalence between mass and energy, E=mc2.

How many photons are required for pair production?

The positron excites and ionizes atoms as it travels through matter in the same way as an electron until it is finally brought to rest. Then the positron combines with one of the free electrons abundant in matter and is annihilated; two annihilation photons, each of 0.511 MeV, are finally produced.

What kind of photons are required to initiate pair production?

Pair production occurs only for gamma-rays of high energy. By that effect the gamma-ray is transformed to matter in the form of a pair of negatively and positively charged electrons (negatron and positron).

How is an electron-positron pair formed?

The formation of an electron-positron pair in a collision between a photon and a nucleus (Z + γ → Z + e− + e+) and electron–nucleus bremsstrahlung (Z + e− → Z + e− + γ) are two cross-channels of the same reaction.

What is pair production and pair annihilation?

The conversion of a photon into an electron-positron pair on its interaction with the strong electric field surrounding a nucleus is called pair production. The converse of pair production in which an electron and positron combine to produce two photons is known as annihilation of matter.

What is pair production & Anti pair production?

Pair production is the creation of a subatomic particle and its antiparticle from a neutral boson. Examples include creating an electron and a positron, a muon and an antimuon, or a proton and an antiproton. Pair production often refers specifically to a photon creating an electron–positron pair near a nucleus.

What is mass of positron?

The positron is the antiparticle of the electron. It has the same mass (9.109×10−31 kg), electric charge (1.602×10−19 C), and spin (1/2) as the electron, but the sign of the charge for the positron is positive, opposite to that of the electron.

How many particles are in a pair?

In a region of strong gravitational tidal forces, the two particles in a pair may sometimes be wrenched apart before they have a chance to mutually annihilate.