Changes between Version 2 and Version 3 of LOEventGenerationBias

Timestamp:

Aug 20, 2016, 2:15:08 AM (8 years ago)

Author:

Valentin Hirschi

Comment:

--

LOEventGenerationBias

@@ -6 +6 @@
 This wiki page will cover the details of how to setup and write your own bias function.
 
+The motivation for using a bias function typically falls in one of the following two categories:
+ * 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.
+ * 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.. 
 
+Before 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'.
 
-{{{OUTPUT_FOLDER_NAME> set bias ptj_bias}}}
+These two plots were both obtained from 10k events, but for the right-hand side one, the matrix element have been biased by the quantity $(\;{p_t(j_1)}/{1000.0}\;)^4$.
+
+[[Image(original_ptj.jpg,500)]] [[Image(ptj_biased.jpg,500)]]
+
+These plots can be straight-forwardly reproduced with (you will need to have {{{install MadAnalysis}}} for the plots to be automatically generated)
+
+{{{
+./bin/mg5_aMC
+MG5_aMC> generate p p > e+ e- j
+MG5_aMC> launch
+MG5_aMC> set bias_module ptj_bias
+MG5_aMC> done
+}}}
+
+== Usage of a bias module