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unscientific
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Homework Statement
[/B]
(a) Find the ratio of cross sections.
(b) Find the cross section for electron-neutrino scattering by first writing down relevant factors.
Homework Equations
The Attempt at a Solution
Part (a)[/B]
These represent the neutral current scattering for the muon-neutrino and neutral/charged scattering for electron-neutrino. Feynman diagrams are given by
Given that there are 2 possibilities for the electronic case, I say ##R = 2##?
Part (b)
Propagator factor is given by ##\frac{1}{P \cdot P - m_w^2}## which in the zero-momentum frame is ##\approx \frac{1}{m_w^2}##.
There are two vertices, so another factor of ##g_w^2##.
Thus amplitude is ##\frac{g_w^2}{m_w^2}##.
By fermi's golden rule, ##\Gamma = 2\pi |M_{fi}|^2 \frac{dN}{dE_0}##.
Cross section is ##d\sigma = \frac{\Gamma}{v_e}##.
How do I proceed?