The tree-level result for muon-pair production,

PHYSICS · Subjective · Fermi University Physics · Particle Physics & Quantum Fields · Particles, interactions and experiment · Particles, interactions and experiment

Symmetry and Flavour, Ch From amplitude to rate: Lorentz-invariant phase space, widths and cross sections

Problem

The tree-level result for muon-pair production, σ(e+e−→μ+μ−)=4πα2/3s=86.8 nb/(s/GeV2)\sigma(e^+e^-\to\mu^+\mu^-) = 4\pi\alpha^2/3s = 86.8\,\mathrm{nb}/(s/\mathrm{GeV^2}), follows from the spin-averaged QED amplitude for massless leptons. Find the cross section at s=10.0 GeV\sqrt s = 10.0\,\mathrm{GeV} (typical of the CESR collider), and compare it with the value 75 pb75\,\mathrm{pb} quoted for PETRA at s=34 GeV\sqrt s = 34\,\mathrm{GeV} by checking the 1/s1/s scaling.

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