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benchmark generation [message #15667]

Tue, 05 November 2013 12:32

Yuri Naryshkin
Messages: 42
Registered: August 2008

continuous participant

From: *desy.de

Hi,
I would like to generate a benchmark reaction and have parameterization from the experiment. Can I use EvtGen for that purpose?

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Re: benchmark generation [message #15668 is a reply to message #15667]

Tue, 05 November 2013 13:00

StefanoSpataro
Messages: 2736
Registered: June 2005
Location: Torino

first-grade participant

From: 2.235.190*

Yes, you need to write your own model, like this.

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Re: benchmark generation [message #15681 is a reply to message #15668]

Wed, 06 November 2013 17:14

Yuri Naryshkin
Messages: 42
Registered: August 2008

continuous participant

From: *desy.de

Thank you Stefano. Can I produce file for that like:
/input/psi2s_jpsi2pi_1k.evt (the same format) to use as benchmark?

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Re: benchmark generation [message #15682 is a reply to message #15681]

Wed, 06 November 2013 17:38

StefanoSpataro
Messages: 2736
Registered: June 2005
Location: Torino

first-grade participant

From: *to.infn.it

Just to understand, exactly which channel you would like to simulate?

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Re: benchmark generation [message #15684 is a reply to message #15682]

Wed, 06 November 2013 20:39

Yuri Naryshkin
Messages: 42
Registered: August 2008

continuous participant

From: *desy.de

First of all inclusive Lambda or antiLambda and then Lambda_c or antiLambda_c at our energy.

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Re: benchmark generation [message #15685 is a reply to message #15684]

Wed, 06 November 2013 21:17

StefanoSpataro
Messages: 2736
Registered: June 2005
Location: Torino

first-grade participant

From: 2.235.190*

You need to take the macros in macro/run, and write your own .dec file, no need to write your model since (at least for lambda) the model already exits.
In some presentations at the older collaboration meetings lambda analysis were shown with also the models which could be used (Lia or Simone talks).

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Re: benchmark generation [message #15688 is a reply to message #15685]

Thu, 07 November 2013 12:11

Yuri Naryshkin
Messages: 42
Registered: August 2008

continuous participant

From: *desy.de

Thank you again Stefano, may I ask you hoe I can simulate lambda-Lambdabar channel with the code EvtLambdaLambdaBar.cc (you've send me) in the frame of EvtGen, e.g. any example for benchmark as in sim_complete.C example there is only example with dec or evt files are presented? We want to do this kind of simulation (and then some other channels) for our forward TOF wall.

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Re: benchmark generation [message #15689 is a reply to message #15688]

Thu, 07 November 2013 12:24

StefanoSpataro
Messages: 2736
Registered: June 2005
Location: Torino

first-grade participant

From: *to.infn.it

Your dec file should be like:

noPhotos
Decay pbarpSystem
1.0 anti-Lambda0 Lambda0 LambdaLambdaBar 1.643;
Enddecay

Decay Lambda0
1.0 p+ pi- PHSP;
Enddecay

Decay anti-Lambda0
1.0 anti-p-pi+ PHSP;
Enddecay

End

where 1.643 is the momentum of your antiproton (in this case it is 1.643, but you can oput your value).

Remember to use EvtGenDirect and set the same momentum value in the sim_complete.

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Re: benchmark generation [message #15690 is a reply to message #15689]

Thu, 07 November 2013 13:05

Yuri Naryshkin
Messages: 42
Registered: August 2008

continuous participant

From: *desy.de

Thank you! Is the value of anti-proton momentum 1.643 in cms system? Is it for the reaction p + pbar -> Lambda + Lambda-bar?

In sim_complete(Int_t nEvents = 10, TString SimEngine ="TGeant3", Float_t mom = 7.24) mom (momentum) is also defined in cms?

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Re: benchmark generation [message #15691 is a reply to message #15690]

Thu, 07 November 2013 13:06

StefanoSpataro
Messages: 2736
Registered: June 2005
Location: Torino

first-grade participant

From: *to.infn.it

No, it is in the lab frame.

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Re: benchmark generation [message #15693 is a reply to message #15691]

Fri, 08 November 2013 13:59

Yuri Naryshkin
Messages: 42
Registered: August 2008

continuous participant

From: *desy.de

Thank you Stefano, I noticed, that Lambda and lambda-bar are decaying in the interaction point, butn they should have a decay path, is it possible to change it? Is there a simple tool or an example (root macro) how to analyze file with simulated events without reconstruction and digitization (sim_complete.root file)?

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