# 2 -> 2 hadronic production cross section

by Safinaz
 P: 1,008 of course you must be doing something wrong... Be careful, when you compute the amplitude squared, you write: $\left|M\right|^{2}= M^{+}M$ with + I denote the dager/hermitian conjugate. So it's practically impossible (even if you define something "wrong" in your procedure) to get negative value out of it...Something you are doing wrong in your calculations. Also please give me to understand better what you did.... Did you work with dirac spinors for example?