Detailed Description

Center-of-mass energy of a quark threshold.

When used in the first argument of the cross section functions objects of this class represent the naive production threshold.

ttbar_xsection(threshold() + 0.5, mu, mt, width, order, options)

is equivalent to

double sqrt_s = ttbar_threshold(mu, mt, order, options) + 0.5;

ttbar_xsection(sqrt_s, mu, mt, width, order, options);