Last modified 5 years ago Last modified on 04/08/12 13:39:58



  1. Frederix and F. Maltoni

Short Description

Analysis and plotting routines for LHE and LHCO event files.

How to use it

MadAnalysis is a fortran-based program, that can be used for simple analysis of events and make plots for events both at parton level (Les Houches Format) and PGS4, LHC Olympics format. As a furhter utility a Perl script (combine-pl) is included in the package that combine plots of different event files in one, to ease comparisons.

The MadAnalysis package is to be unpacked in the main MG/ME base directory to work!

To compile, just type:

make restore

To make plots of events type

./plot_events file.lhe 


./plot_events file.lhco

A file is produced. This is a ASCII file that can be intepreted and/or transformed to a postscript file by topdrawer (that needs to be installed independently):

td -d postscript

As an alternative, an ascii file that can be read by gnuplot is produced. See the ma_card.dat to set this option.

N.B. Event files ARE expected to have either .lhe or .lhco extensions.

This directory also contains a script, combine-pl, that allows distributions for different event sets to be plotted automatically onto one graph. An example is given in the "script" where plots for events at parton-level and at the PGS level are combined into one set of plots to explicitly see the effects of the detector smearing and resolutions on the typical plots (p_t, eta,...).

Plots are normalized as number of events/bin. Events are considered of weight one if unweighted. If weighted (only for lhe files), the unit weight corresponds to the average one. Total cross section is reported in the info box. Total number of events and events falling in the plots are also given.

Plots are for classes of particles. Classes are defined in the card file ma_card.dat. The syntax is transparent. Each particle is identified by its PDG code. Classes names are arbitrary. Particles in the same class are ordered in pt, but this can be changed in the file kin_func.f to any other ordering function.

So, for instance, by defining:

jet  21  1  -1  2  -2  3  -3  4  -4  5  -5
lept 11 -11 13 -13 15 -15
mET  12 -12 14 -14 16 -16

a jet here contains gluons and u,d,s,c,b and their antiparticles. For example, jet(3) is the third jet in pt.

mET is the missing energy and its name is reserved.

Classes can be edited at will, and given a name that will then appear in the plots (no spaces in the name).

There are 13 build-in varables and 12 user-definable variables that can be plotted. These variables can be found in the file kin_func.f. To plot one of these variables put the corresponding name and the particles that you want to plot in the ma_card.dat.

Some comments about the plots (format):

  1. In the file kin_func.f the functions can be found that can be plotted.
  2. With the plotting options one can set the number of plots for each of these functions.
  3. One has to specify for each variable which particles from which class are used to set the plots. Syntax:
          et  2 4                                                           
    means that the transverse energy of the first four particles in the second class will be plotted.
         mij 1 3                                                           
         mij 2 2                                                           
    means that for the invariant mass plots the first three particles from the first class and the first two from the second class will be used to plot the invariant mass of two particles. (10 plots)
  4. The ordering of the particles in a class can be set with the 'ordering function' in the file kin_func.f.
  5. Max number of plots is 200.

Cuts can be set on the same variables. They can be defined in the same ma_card.dat. The Syntax is transparent.

Some comments about the cuts:

  1. In the file kin_func.f the functions on which cuts can be applied are given.
  2. The syntax is as follows.
          etmin 1 3 30d0                                                     
    means that from the first class the Et of the first three particles has to be greater than 30 GeV.
         etmissmin 20d0                                                     
    means that there must be at least 20 GeV of missing Et
         dRmin 2 1 4 3 3d0                                                  
    means that the distance between the first particle in the second class and the first three particles in the fourth class has to be greater than 3.
         ptmax 1 3 10d0                                                     
         ptmax 1 2 15d0
    means that the maximum pt of the third particle in the first class has to smaller than 10 GeV, and the first two particles of this class has to be smaller than 15 GeV
  3. The ordering of the particles within a class can be set with the 'ordering function' in the file kin_func.f.
  4. For all the 'min' cuts, an event will be thrown away if the particle does not exist. On the other hand, for all the 'max' cuts the cut will be ignored if the particle does not exist (Only dRij is an exception, for which it is the other way around)

Questions and Answers

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-- Main.FabioMaltoni - 01 Aug 2007