Nuclear & Particle Physics - Conservation Laws

The muon decays with a characteristic lifetime of about 10⁻⁶ second into an electron, a muon neutrino, and an electron antineutrino. The muon is forbidden from decaying into an electron and just a single neutrino by the law of conservation of

A. charge
B. mass
C. energy and momentum
D. baryon number
E. lepton number

(GR0177 #78)

Solution:

If  μ → e⁻ + ν

A. FALSE. Conservation of charge: − 1 → − 1 + 0 is not violated.

B. FALSE. Conservation of mass cannot be violated in any decay/interactions.

C. FALSE. Conservation of energy and momentum cannot be violated in any decay/interactions.

D. FALSE. Muon is a lepton. It follows the Conservation of Lepton Number, not Baryon Number.

E. TRUE. Lepton Numbers: 1 → 1 + 1 is violated.

Answer: E