This short piece of code takes in fixed laboratory angles and converts them to their corresponding center of mass frame angle. Written for converting angular distributions from lab to CM frame.
Given the kinematics for your reaction, this code converts lab angles (typically ranging from 15-60 degrees in 5 degree steps as the SE-SPS) and outputs their corresponding CM angle. Simply changing the mass inputs and updating lab angles by preference is all that is needed to use for other reactions of the type A(a,b)B.