different results of mirror sub-processes

Here there is asymmetry for pseudo-rapidity eta (Y in CalcHEP).
One should set symmetry cut for pseudo-rapidity
     -2.5 < Y(A) < 2.5

Please, improve cuts and let us know if difference still exists.

Best
    Alexander Pukhov

On 12/15/2017 05:12 AM, Shao-Feng Ge wrote:
> New question #661796 on CalcHEP:
> https://answers.launchpad.net/calchep/+question/661796
>
> I'm calculating the cross section of pp->AA. So there are several subprocesses, including the mirror processes:
>
> u,U -> A,A vs U,u -> A,A
>
> Since both u and U are from proton beams, say each with 6.5GeV, I would expect the mirror processes would have the same cross section:
>
> sigma(u,U -> A,A) = sigma(U,u -> A,A)
>
> However, what I get from CalcHEP is
>
> sigma(u,U -> A,A) = 2.68 fb
> sigma(U,u -> A,A) = 5.10 fb
>
> I obtained this in both GUI & batch modes. For clarity, I paste the batch code below.
>
> These numbers are also different MadGraph results: sigma(pp->AA) = 4.8fb, including all subprocesses.
>
> Any idea?
>
> ----------------------------------------------------------------------
>
> Model: Standard Model
> Model changed: False
> Gauge: Feynman
> Composite: p=u,U,d,D,c,C,s,S,b,B
> Process: p,p->A,A
>
> pdf1: cteq6l1 (proton)
> pdf2: cteq6l1 (proton)
>
> p1: 6500
> p2: 6500
>
> Cut parameter: M(A,A)
> Cut invert: False
> Cut min: 1000
> Cut max:
>
> Cut parameter: T(A)
> Cut invert: False
> Cut min: 10
> Cut max:
>
> Cut parameter: Y(A)
> Cut invert: False
> Cut min:
> Cut max: 2.5
>
> Dist parameter: M(A,A)
> Dist min: 1000
> Dist max: 13000
> Dist n bins: 24
> Dist title: pp->AA
> Dist x-title: M(AA) [GeV]
>
> Filename: SM
>

Yes, this does solve the problem. Thanks.