Analytical expression of cross-section for polarized beam in calchep

Asked by Sahabub Jahedi on 2020-09-27

Dear authors,
                         I am to trying to calculate the analytical cross-section of pair production of charged higgs at ILC(i.e electron-positron collison). Now, if I want to chose the electron beam to be +80% polarized and the positron beam to be -20% polarised then is it possible to calculate the analytical cross-section in calchep?

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Alexander Belyaev
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Sahabub Jahedi (sabuj27) said :
#1

I am to trying to calculate the analytical cross-section of pair production of charged higgs at ILC(i.e electron-positron collison) for Inert doublet model(IDM).

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Alexander Belyaev (alexander.belyaev) said :
#2

You did not ask any question here.
What is your question?

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Sahabub Jahedi (sabuj27) said :
#3

I apologize for incomplete information.

I am to trying to calculate the analytical cross-section of pair production of charged higgs(H^+) at ILC(i.e electron-positron collison) for Inert doublet model(IDM). The process is e^+e^- --> H^+ H^-$ with Photon and $Z$ mediation. Now, if I want to chose the electron beam to be +80% polarized and the positron beam to be -20% polarised then is it possible to calculate the analytical cross-section in calchep??

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Best Alexander Belyaev (alexander.belyaev) said :
#4

Hello,
yes it is possible.
If you use "%" in symbolic session, then
analytical results for for example this process
e%,E% --> H+, H-
will have "Helicity" in the matrix elements squared which controlls
electron(positron) polarisation:
Helicity ranges between -0.5 (100% Left polarised) and +0.5(100% riht polarised
So when you output symbolic results in , for example, Mathematica code
you will get what you are asking
Regards,
Alexander

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Sahabub Jahedi (sabuj27) said :
#5

Thanks Alexander Belyaev, that solved my question.