Changes between Version 6 and Version 7 of LoopInducedTimesTree

Timestamp:

Sep 8, 2016, 7:12:27 AM (8 years ago)

Author:

Valentin Hirschi

Comment:

--

LoopInducedTimesTree

@@ -2 +2 @@
 
 This page describes the technical modifications necessary to compute the interference of loop-induced diagrams with tree-level diagrams using MadEvent and the Loop-Induced module of MG5aMC.
-Notice that there is as of now '''no official support for such computation in MG5aMC''', so that the procedure below must be performed with care and should be cross-checks in some limits since '''we cannot guarantee the same level of reliability as with other MG5aMC functionalities'''.
+
+Notice that there is as of now 
+
+'''no official support for such computation in MG5aMC'''
+
+, so that the procedure below must be performed with care and should be cross-checks in some limits since 
+
+'''we cannot guarantee the same level of reliability as with other MG5aMC functionalities'''.
+
 It was however already successfully used and tested for 'g g > h > t t~ g'  X 'g g > t t~ g'.
 
@@ -89 +97 @@
             ref_orders = [lao[0] for lao in loop_orders+ct_amp_orders+uvct_amp_orders]
 }}}
-
+>c.4) On MG5aMC versions below or equal to 2.5.0: around line 480 of the file '<MG_root_path>/madgraph/madevent/gen_ximprove.py' change:
+{{{
+            ratio = th_maxwgt[-1][0]/th_maxwgt[-2][0]
+}}}
+to
+{{{
+            ratio = th_maxwgt[-1][0]/max(th_maxwgt[-2][0],1.0e-99)
+}}}
 d) Now that all the necessary modifications have been performed, you should be able to run the code for simulation of the loop-induced vs tree interference as follows:
-> d.1) First start the interface by running the script './bin/mg5' from within the directory <MG_root_path>
+> d.1) First start the interface by running the script './bin/mg5' from within the directory <MG_root_path>. Make sure to always generate a new process from a freshly started interface, since the above changes introduce border effects affecting subsequent process generations from the same MG5aMC interactive session.
 > d.2) Whenever you plan on running event generation (i.e. not necessary when doing MadLoop standalone), make sure that the grouping of subprocess is disabled. Note that disabling the subprocess grouping optimization is no longer a requirement when starting this procedure from MG5aMC v2.5.0 and beyond.
 {{{