Changes between Version 2 and Version 3 of LOEventGenerationBias


Ignore:
Timestamp:
08/20/16 02:15:08 (4 years ago)
Author:
Valentin
Comment:

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  • LOEventGenerationBias

    v2 v3  
    66This wiki page will cover the details of how to setup and write your own bias function.
    77
     8The motivation for using a bias function typically falls in one of the following two categories:
     9 * a) Producing smoother distributions for the tail of a particular observable. This means that physical results obtained in presence of the bias will be identical but sampled differently.
     10 * b) One wants to modify the integrand so as to really impact the physical results. This can be useful for a plethora of applications: ad-hoc unitarisation of the matrix elements, merging weights, inclusion of higher order contributions, etc..
    811
     12Before going into the detail of the usage of the bias module and the instructions for building your customized bias, we present here an example of their use for the case a) above to smoothen the distribution of the jet transverse momentum for the process 'p p > e+ e- j'.
    913
    10 {{{OUTPUT_FOLDER_NAME> set bias ptj_bias}}}
     14These two plots were both obtained from 10k events, but for the right-hand side one, the matrix element have been biased by the quantity $(\;{p_t(j_1)}/{1000.0}\;)^4$.
     15
     16[[Image(original_ptj.jpg,500)]] [[Image(ptj_biased.jpg,500)]]
     17
     18These plots can be straight-forwardly reproduced with (you will need to have {{{install MadAnalysis}}} for the plots to be automatically generated)
     19
     20{{{
     21./bin/mg5_aMC
     22MG5_aMC> generate p p > e+ e- j
     23MG5_aMC> launch
     24MG5_aMC> set bias_module ptj_bias
     25MG5_aMC> done
     26}}}
     27
     28== Usage of a bias module