Name: mariam Date: 12/03/08-02:37:57 PM Z


I am very badly in need of solvin the following problem.
I have combination of spinor chains in the amplitude with structures like e.g.
1)[(Spinor[P/2+-q,M].___. Spinor[P/2-+q],M)*(Spinor[k1,M].____.Spinor[k2,M])]

2) [(Spinor[P/2+-q,M].___. Spinor[anyk,M])*(Spinor[P/2-+q,M].____.Spinor[anyk,M])]

(Note that M is same in all)
I have a large number of diagrams. Now I want to read these chains like:

Spinor[anyk,M].___.Spinor[anyk,M]
Spinor[P/2+-q,M].___.Spinor[P/2-+q,M]
Spinor[P/2+-q,M].___.Spinor[anyk,M] or vice versa

I have successfully separated out the 1st chain (Spinor[anyk,M].___.Spinor[anyk,M]) but my if loop is not working for the rest of two.What I wrote is:

If[FreeQ[chain22[i1,i2,i5],Xor[Spinor[a_+b_,MC,___],Spinor[a_-b_,MC,___]]],
{condition1},{condition2}]

I mean Xor is true if the chain contains odd number of Spinor[P/2+-q,M].

Help out please……….