NuWro - Wrocław Neutrino Events Generator
by Wrocław Neutrino Group
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Frequently Asked Questions


NUWRO calculates cross-section in unit of cm2. But I am not sure whether it is cm2/nucleon or cm2/atom correctly.

It is always in cm2 per nucleon. So that eg for CCQE on carbon in order to get CCQE per nucleus you must multiply the output by 12 and if you are interested (as often happens) in CCQE per bound neutron, you must multiply by a factor of 2.

NuWro without formation zone

How can I run NuWro with formation time/zone switched off?

You should put line:

formation_zone = nofz
to your params.txt or run nuwro as follows
nuwro -p "formation_zone=nofz"

Particles in the output file

Output root file has "in", "tmp", "out", "post" particle information. I would like to know clear definitions of these labels, especially about "tmp" and "post", although I can guess.

In a nuwro event there are five vectors of particles:

  • IN particles are neutrino and one nucleon.
  • TMP particles are DIS temporary particles.
  • OUT -- final state of the primary vertex (before reinteraction)
  • POST -- particles that leave the nucleon and can be detected.
  • ALL -- IN, OUT, intermediate particles of the intranuclar cascade and POST. This is used only for debugging.

Which params.txt is used?

I have params.txt file in the working directory (/nuwro) and also in /nuwro/data . Which one is read once the code is being executed?

The one in /nuwro. Only if there is no params.txt in the working directory, the file from /nuwro/data is read.

In fact your working directory does not need to be nuwro. If /nuwro/bin is in the $PATH than you can

mkdir work
cd work
edit params.txt
the file work/params.txt will be used if it exists, otherwise /nuwro/data/params.txt will be used. The same aplies to all files included (@) from params.txt

event::q2() does not work when used from root

I have pulled a new version of nuwro and the q0(), q2() event methods no longer work when using bin/myroot in the analysis.

The ROOT dictionary did not build correctly. Try the following steps:

cd nuwro
make distclean
to force a full rebuild.

Nucleus not present in the in, out, post vectors

Why is information about nucleus not present in the in, out, post vectors?

The 'in','out','post' vectors contain only informaction about elementary particles.

The 'in' vector contains the trajectile neutrino and the particular nucleon on which the primary vertex interaction took place.

The 'post' vector contains only the particles which leave nucleus and can be tracked by a detector specific MC code.

The information about initial nucleus is contained in 'par' - copy of the initial parameters, which is found in every event . The values 'par.nucleus_p' and 'par.nucleus_n' specify the element on which that particular event took place.

The numer of protons and neutrons in the residual nucleus is stored in the 'pr', 'nr' fields of the event structure.

copyright © 2010-13 C. Juszczak