Changing Incoming State Momenta

On 2/7/24 08:55, Sayan Kr. Das wrote:
> New question #709228 on CalcHEP:
> https://answers.launchpad.net/calchep/+question/709228
>
> Hello. I am new to CalcHep and cannot figure out how to run a batch file where you change the incoming particle momenta.
##############################################
#  Momentum Info                              #
#    in GeV                                   #
###############################################
p1:        4000
p2:        4000

Also

pdf1:      PDT:cteq6l1(proton)
pdf2:      PDT:cteq6l1(proton)

has to be replace on

pdf1:      OFF
pdf2:      OFF

You also can use  par_scan    script

Best

     Alexander Pukhov

> To elaborate on this, I am studying the scattering ne + ne -> ne + ne + A. I need the differential cross-section wrt the photon energy for a large range of incoming particle energy. Any help would be appreciated. Thank you!
>

Hi! Thank you for your response. The par_scan script was just what I needed. However there is still a problem.

For each value of p_cm, I want a distribution (particularly cross section vs photon energy). In the CalcHep manual, it is written that there is an option for setting distributions and showing them. I don't know how to do this. Any hep would be appreciated.

On 2/9/24 05:10, Sayan Kr. Das wrote:
> Question #709228 on CalcHEP changed:
> https://answers.launchpad.net/calchep/+question/709228
>
> Status: Answered => Open
>
> Sayan Kr. Das is still having a problem:
> Hi! Thank you for your response. The par_scan script was just what I
> needed. However there is still a problem.
>
> For each value of p_cm, I want a distribution (particularly cross
> section vs photon energy). In the CalcHep manual, it is written that
> there is an option for setting distributions and showing them. I don't
> know how to do this. Any hep would be appreciated.

Just generate  numerical code for your processes and see which
distribution CalcHEP proposed for your incoming particles ( electrons).

I hope it is  just you need.

Best

     Alexander Pukhov

Dear Sayan,

you can scan over the energy in the batch session too.

the lines with the fixed energy, in the batch file e.g.

p1:        4000
p2:        4000

can be replaced with

p1: 1000*rtS/2
p2: 1000*rtS/2

Run parameter: rtS
Run begin: 7
Run step size: 1
Run n steps: 4

which will perform the scan over the rtS parameter.
"rtS" is not a parameter of the model,
this name can be any name you like (different from the model parameters)

These lines will allow to perform the scan over 7  points : p1,p2 =
3500,4000,4500,5000
Eventually you can change these numbers as you wish.

On 09/02/2024 07:40, Alexander Pukhov wrote:
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>
> CAUTION: This e-mail originated outside the University of Southampton.
>
> Question #709228 on CalcHEP changed:
> https://answers.launchpad.net/calchep/+question/709228
>
> Status: Open => Answered
>
> Alexander Pukhov proposed the following answer:
>
> On 2/9/24 05:10, Sayan Kr. Das wrote:
>> Question #709228 on CalcHEP changed:
>> https://answers.launchpad.net/calchep/+question/709228
>>
>> Status: Answered => Open
>>
>> Sayan Kr. Das is still having a problem:
>> Hi! Thank you for your response. The par_scan script was just what I
>> needed. However there is still a problem.
>>
>> For each value of p_cm, I want a distribution (particularly cross
>> section vs photon energy). In the CalcHep manual, it is written that
>> there is an option for setting distributions and showing them. I don't
>> know how to do this. Any hep would be appreciated.
> Just generate numerical code for your processes and see which
> distribution CalcHEP proposed for your incoming particles ( electrons).
>
> I hope it is just you need.
>
> Best
>
> Alexander Pukhov
>
> --
> You received this question notification because your team CalcHEP is an
> answer contact for CalcHEP.

--
................................
Professor Alexander S Belyaev
https://www.soton.ac.uk/~ab1u06
.......
Physics & Astronomy 46/5047
University of Southampton
Southampton SO171BJ
................................

Okay. This is an elegant solution that completely escaped my mind. Thank you very much. I shall try this solution. If I don't encounter any more problems, I shall marks the question as 'solved'.

You have my sincerest gratitude.

So I tried the batch file script on a simple process first: e,E->A,A
It's working as it should. It gave me the distributions. But there is a small problem. There are three options in the homepage of index.html: symbolic results, numerical results and the event library. The problem is with the last one. The script keeps on running and the 'Events' task does not finish. If you could comment on the batch file I would be grateful. Here is the link.

https://drive.google.com/file/d/1M5Xb3T6HsoevMsEf5Jr_OTIGarpGW4y5/view?usp=drive_link

Thank you in advance.

Thanks Alexander Belyaev, that solved my question.