A charged pion

PHYSICS · Multi-part · Fermi University Physics · Relativity & Gravitation · Relativistic dynamics and fields in flat spacetime · Relativistic dynamics and fields in flat spacetime

Particle Physics, Ch Scales, units and the four-momentum

Problem

A charged pion, rest mass mπ=139.6 MeV/c2m_\pi = 139.6\,\mathrm{MeV}/c^2, has momentum magnitude ∣p∣c=300 MeV|\mathbf p|c = 300\,\mathrm{MeV} in the laboratory frame. ((a)) Convert mπm_\pi to kilograms, using 1 eV=1.602176634×10−19 J1\,\mathrm{eV} = 1.602176634\times10^{-19}\,\mathrm{J} and c=2.99792×108 m s−1c = 2.99792\times10^8\,\mathrm{m\,s^{-1}}. ((b)) Find the pion's total energy EE, kinetic energy TT, speed parameter β\beta and Lorentz factor γ\gamma. ((c)) Form the invariant product p⋅pp\cdot p of the pion's four-momentum with itself, in MeV2/c2\mathrm{MeV^2}/c^2, and check it against mπ2c2m_\pi^2c^2.

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