Formula for the differential cross-section is missing a factor

[fhagemann]

I just checked the formula for the differential cross section formula in Schwartz (2014):

Seems like this template is missing the |p|/ |k| in the docstring here:

HEPExampleProjectTemplate.jl/src/cross_section.jl

Line 24 in 1daa844

\\frac{\\mathrm{d}\\sigma}{\\mathrm{d}\\Omega} = \\frac{\\alpha^2}{16 E_{\\mathrm{in}}^6}\\left( E_{\\text{in}}^4 + \\rho_e^2 \\rho_\\mu^2 \\cos^2\\theta + E_{\\text{in}}^2 \\left( m_e^2 + m_\\mu^2 \\right) \\right)