Name: V. Shtabovenko Date: 11/19/17-02:06:09 PM Z
Hi,
sorry for the late reply. SetMandelstam can do this
?SetMandelstam
SetMandelstam[x, {p1, p2, p3, p4, p5}, {m1, m2, m3, m4, m5}]
defines \
x[i, j] = (pi+pj)^2 and sets the pi on-shell. The pi satisfy: p1
SetMandelstam[x, {p1, p2, p3, p4, p5}, {m1, m2, m3, m4, m5}];
SP[p1 + p2] // ExpandScalarProduct
SP[p1 + p5] // ExpandScalarProduct
Cheers,
Vladyslav
Am 15.11.2017 um 19:59 schrieb Francesco:
> Hello,
> I need to compute a 2->4 amplitude within a model I created.
> In order to simplify the expression for the amplitude, is there a
way to use the generalised Mandelstam variables like
> s_{i1i2..i4}=(p_i1+…+p_i4)^2
> and the others possible combinations?
>
> thanks
>