Wrong value of Crosssection is showing for a particular process and the plots are generating for infinite time.. need to do ctrl+C to finally stop

Hello,

since you did not apply the cut on the photon transevrse momentum or
energy, this process is divergent.

So it is not surprising that you are getting absurd numbers, since the
numbers without kinematical cut on the photon have no sense.

One of the indicators of the divergence is the accuracy for the MC
integration -- always keep an eye on it.

If the accuracy is bad -- the is a problem, typically related to the
absend of the kinematical cuts and(or) regularisation(s).

Regards,

Alexander

On 10/02/2020 14:23, Atanu Guha wrote:
> New question #688646 on CalcHEP:
> https://answers.launchpad.net/calchep/+question/688646
>
> Hi ...
> I am facing a strange issue regarding a particular process...
> If I look for the process... e- e+ > ne, Ne , calcHEP is running smoothly, producing all the relevant plots, giving the correct value of the crosssection and finally stopping automatically after complete execution.
>
> But in case I want to look for the process e- e+ > ne, Ne , A ; where I include a photon as ISR, calcHEP is giving some absurd value of the crosssection and the plots are not producing at all, finally I need to stop the process manually (ctrl+c).
>
> Please find my batch file below... please suggest me the possible solutions
> ***************************************************************************************************************
> #Model: SM(+hgg)
> Model: SM
> Model changed: False
> Gauge: Feynman
> Process: e,E->n,N,A
>
> Composite: n=ne,nm
> Composite: N=Ne,Nm
>
> Kinematics : 12 -> 34 , 5
> Kinematics : 34 -> 3 , 4
>
> pdf1: ISR & Beamstrahlung
> pdf2: ISR & Beamstrahlung
>
> Bunch x+y sizes (nm) : 480
> Bunch length (mm) : 0.3
> Number of particles : 2E+10
>
> p1: 500
> p2: 500
>
> Regularisation momentum: 12
> Regularization mass: MZ
> Regularization width: wZ
> Regularization power: 2
>
> Regularisation momentum: 34
> Regularization mass: MZ
> Regularization width: wZ
> Regularization power: 2
>
> Regularisation momentum: 13
> Regularization mass: MW
> Regularization width: wW
> Regularization power: 2
>
> Regularisation momentum: 24
> Regularization mass: MW
> Regularization width: wW
> Regularization power: 2
>
> Regularisation momentum: 24
> Regularization mass: MW
> Regularization width: wW
> Regularization power: 2
>
> Regularisation momentum: 14
> Regularization mass: MW
> Regularization width: wW
> Regularization power: 2
>
> Dist parameter: M(n,N)
> Dist min: 0
> Dist max: 600
> Dist n bins: 100
> Dist title: e,E->n,N,A
> Dist x-title: M(n,N) (GeV)
>
> Dist parameter: N(A)
> Dist min: -5
> Dist max: 5
> Dist n bins: 300
> Dist title: e,E->n,N,A
> Dist x-title: N(A)
>
> Dist parameter: T(A)
> Dist min: 0
> Dist max: 600
> Dist n bins: 100
> Dist title: e,E->n,N,A
> Dist x-title: T(A) (GeV)
>
> Dist parameter: J(n,N)
> Dist min: 0
> Dist max: 7
> Dist n bins: 300
> Dist title: e,E->n,N,A
> Dist x-title: J(n,N)
>
> Number of events (per run step): 10000
> Filename: ee_neNeA
>
> NTuple: False
> Cleanup: False
> Max number of cpus: 8
>
> nSess_1: 5
> nCalls_1: 100000
> nSess_2: 5
> nCalls_2: 100000
> ***************************************************************************************************************
> Regards.
>
> Atanu
>
>
--
______________________________________________________________________
Prof. Alexander S Belyaev (<email address hidden>)
https://www.hep.phys.soton.ac.uk/content/alexander-belyaev

School of Physics & Astronomy, University of Southampton
Office 5047, SO17 1BJ, TEL: +44 23805 98509, FAX: +44 23805 93910
.....................................................................
Particle Physics Department, Rutherford Appleton Laboratory
Didcot, OX11 0QX, TEL: +44 12354 45562, FAX: +44 12354 46733
.....................................................................
CERN, CH-1211 Geneva 23, Switzerland
Office 40/1-B20, Mailbox: E27910, TEL: +41 2276 71642
______________________________________________________________________

Thank you very much for pointing it out.
I am very new to use calcHEP.

Please help me with a one liner sample on how to apply the cut on the photon transevrse momentum, pT or
energy E.

Thanks Alexander Belyaev, that solved my question.