Skip to content

Latest commit

 

History

History
80 lines (55 loc) · 2.91 KB

README.md

File metadata and controls

80 lines (55 loc) · 2.91 KB

Running the WHIZARD event generator

WHIZARD is a matrix element generator that is and has been extensively used for linear collider physics studies.

For more information, documentation and more advanced tutorials see the WHIZARD-homepage at: https://whizard.hepforge.org.

In this tutorial we will show you a very simple example for how to run Whizard to generate some events for the process

  • $e^+e^- \rightarrow ZH$ with $Z\rightarrow \mu^+ \mu^-$ for the ILC at $E_{cms}=250$ GeV.

Setup

If you haven't done it yet, source a Key4hep software environment via

source /cvmfs/sw.hsf.org/key4hep/setup.sh

and create a working directory for this exercise:

mkdir work_whizard
cd work_whizard

Run the generator

Download the example steering file ./zhiggs.sin or use wget:

wget https://raw.githubusercontent.com/key4hep/key4hep-tutorials/main/whizard_gen/zhiggs.sin

And then you can generate your first events with WHIZARD:

whizard zhiggs.sin

Inspect the output file

If the above has worked there are many files created by WHIZARD. We are here only interested in the actual event output file: zhiggs.slcio. This is an LCIO file that can be analysed with the usual tools, e.g. we can dump the record of the 3rd event:

dumpevent zhiggs.slcio 3 | less

Exercise: use the dumpevent tool to look at the MC-truth record.

  • Have we generated the right events for the process ($e^+e^- \rightarrow ZH$ with $Z\rightarrow \mu^+ \mu^-$) ?
  • Have we generated the correct center of mass energy ?

Answering the second question with dumpevent might be a bit cumbersome, though.

Take a look at this python script ./lcio_mcparticle.py to see how this could be answered in a programmatic way using the LCIO Python bindings.

python lcio_mcparticle.py zhiggs.slcio

Modify the WHIZARD steering file

In the last exercise we have seen that the example steering file does not yet produce the output file that we actually want. Now it is rather straight forward to fix:

Exercise: modify the zhiggs.sin file to actually create what we want:

  • events for the process: $e^+e^- \rightarrow ZH$ with $Z\rightarrow \mu^+ \mu^-$
  • a correct beam spectrum for the ILC at $E_{cms}=250$ GeV
  • more than 10 events (e.g. 10k)
  • output file name zh_mumu.slcio

Hints: WHIZARD uses its own language SINDARIN for the steering files and needs so called circe files for the beam energy spectrum - see http://whizard.hepforge.org/manual and http://whizard.hepforge.org/circe_files.

If you are done you should be able to see sth. like this:

python lcio_mcparticle.py zh_mumu.slcio
#  Loading LCIO ROOT dictionaries ...
#  <E_cms> =  247.65331134473922   from  10000  events