Demo of Vegas with Z->bbg

Tree level decay of Z->bbg with cuts in y1 and y2 (y1> yc and y2> yc). It computes the integral by Monte Carlo and then it generates unweighted events distributed as phase-space*amplitude (and keeps improving the integral). You can choose mb, yc and the number of events (in thousends). You can also choose to see the Vegas grid and also how the weighted events generated by Vegas are distributed. Finally you can also choose a regularized version of the integration (change of variables y1=yc**x1 and y2=yc**x2 to improve the performance).