KDecayPions < NA62

---+ Pions from in-beam Kaon Decay

Pions from in-beam Kaon Decay

%TOC%

---++ Generator

This case is handled via =pichdecays.F=. This file is a container for charged pion decays. <br>
The routine =pichdecay_manager= is called in kaon decay generators where one ore more charged pions are present in the final state (e.g. =kch2pipi0.F=). <br>
Two pion decay types are implemented in =pich2lnu.F= and =pich2lnug.F=, with the possibility to choose the lepton type (electron or muon).

---++ Software implementation

New generator files:
   * =Generator/pichdecays.F=
   * =Generator/pich2lnu.F=
   * =Generator/pich2lnug.F=
Generator to be modified:
   * =Generator/kch2pipi0.F=

Macro file to be modified:
   * =macros/StandardRun.mac=

C++ files to be modified:
   * =src/CMC.cc=, =include/CMC.hh=
   * =src/DatacardManager.cc=, =include/DatacardManager.hh=
   * =src/DatacardMessenger.cc=, =include/DatacardMessenger.hh=

---++ How to run

To run this channel:
   * specify the charged pion decay type in the =StandardRun.mac= file, at the line with the tag =/decay/pichDecay=. <br>
   Available charged pion decay types:
      * 0: pi is passed to Geant4;
      * 1: pi-->mu nu;
      * 2: pi-->e nu;
      * 3: pi-->mu nu g;
      * 4: pi-->e nu g;

Run the software giving the modified macro file as input parameter, e.g. on an SL6 machine:
<verbatim>
cd /afs/phas.gla.ac.uk/data/na62/software01/NA62MC
source scripts/env.sh
NA62MC macros/StandardRun.mac
</verbatim>

In the =StandardRun.mac= file, one has to pay attention to the following instructions:
<verbatim>
/decay/pichDecay 2 
</verbatim> 
as explained above. Then use

<verbatim>
/output/fileName pluto.root
</verbatim>
to set where the output goes. 

Verbosity can be set with
<verbatim>
/run/verbose 1
/event/verbose 1
/tracking/verbose 1
</verbatim>

---++ How to check the output

An event analyzer is provided inside the *NA62Analysis* framework.

In =/afs/phas.gla.ac.uk/data/na62/software01/UserAnalysis= the "MCTruthAnalyzer" can be used to debug the MC events produced with !NA62MC. <br>
   * The code is in =Analyzers/src/MCTruthAnalyzer.cc=

After sourcing =scripts/env.sh= from within =UserAnalysis/=
   * Compile with =NA62AnalysisBuilder.py configFiles/MCTruthAnalyzer.conf=
   * Run with =./MCTruthAnalyzer -i ../NA62MC/pluto.root -o test.root -v kUser --config configFiles/MCTruthAnalyzer.run= <br>
     The =kUser= verbose flag has to be used to get on screen information on generated particles.

---++ Documentation

This will be documented in technical note CERN-
This topic: NA62 > WebHome > KDecayPions
Topic revision: r6 - 2015-04-20 - DanProtopopescu