- #1

Uncle_John

- 15

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## Homework Statement

Calculate the ratio of scattering cross sections for hadron and muon production

[itex] \sigma(e^{+} e^{-} \rightarrow hadrons) / \sigma(e^{+} e^{-} \rightarrow \mu^{+}\mu{-})[/itex],

just underneath and just a bit above the treshold for quark production [itex]t \bar{t}[/itex]

(Note only the exchange of the photons)

## Homework Equations

Equation for cross section(i think):

[itex]\sigma = \frac{K}{(M_{invariant} - M)^2 c^4 + (\frac{\Gamma}{2})^2} [/itex]

What represents the [itex]\Gamma[/itex] in this equation?

How do i calculate the treshold for above productions

Any help appreciated