A positively charged particle produced in a fixed-target experiment has momentum
PHYSICS · Multi-part · Fermi University Physics · Particle Physics & Quantum Fields · Particles, interactions and experiment · Particles, interactions and experiment
Particle Physics, Ch The particle zoo and the four interactions
Problem
A positively charged particle produced in a fixed-target experiment has momentum p=600MeV/c, from the curvature of its track, and speed β=0.450, from the ionisation density along the track. Many such tracks, all at this momentum, end in a decay after a mean distance of L=1.21cm in the laboratory.
((a)) Find the particle's rest mass m, and identify it from these candidates: K+ (493.7MeV/c2), proton (938.3MeV/c2), Σ+ (1189.4MeV/c2).
((b)) Find its mean lifetime τ in its own rest frame.
((c)) State which fundamental interaction is responsible for the decay.