Most elementary particles (see Chapter 14) are not stable, and physicists have measured...

Most elementary particles (see Chapter 14) are not stable, and physicists have measured their mean lifetime . Consider the uncertainty that this places on their mass-energy. The energy spread is the full width of the particle’s energy distribution at half its maximum value. (a) If we relate = Δt and = 2 ΔE, what is the relation in terms of the uncertainty principle? (b) What is the energy spread in the massenergy of the following particles with their mean lifetimes in parentheses: neutron (886 s), charged pion π^- or π⁺ (2.6 × 10^-8 s), and upsilon (1.2 × 10^-20 s)?