[Rivet-svn] r2401 - trunk/src/Analyses

[blackhole at projects.hepforge.org]

Author: fsiegert
Date: Tue Apr 13 21:04:54 2010
New Revision: 2401

Log:
Fix for histogram normalisation in D0 2008 photon+jet analysis. After
emailing with the author I am convinced, that the external 2-dimensional
binwidth of these histograms has to be reduced by a factor 1/2 because
of the y_gamma * y_jet requirement on each histogram.

Modified:
   trunk/src/Analyses/D0_2008_S7719523.cc

Modified: trunk/src/Analyses/D0_2008_S7719523.cc
==============================================================================
--- trunk/src/Analyses/D0_2008_S7719523.cc	Tue Apr 13 12:42:10 2010	(r2400)
+++ trunk/src/Analyses/D0_2008_S7719523.cc	Tue Apr 13 21:04:54 2010	(r2401)
@@ -158,10 +158,13 @@
                 *_h_forward_opp_cross_section)->scale(dy_jet_forward/dy_jet_central, 1);
    
       // Use generator cross section for remaining histograms
-      scale(_h_central_same_cross_section, 1.0/lumi_gen * 1.0/dy_photon * 1.0/dy_jet_central);
-      scale(_h_central_opp_cross_section, 1.0/lumi_gen * 1.0/dy_photon * 1.0/dy_jet_central);
-      scale(_h_forward_same_cross_section, 1.0/lumi_gen * 1.0/dy_photon * 1.0/dy_jet_forward);
-      scale(_h_forward_opp_cross_section, 1.0/lumi_gen * 1.0/dy_photon * 1.0/dy_jet_forward);
+      // Each of these needs the additional factor 2 because the
+      // y_photon * y_jet requirement reduces the corresponding 2D "bin width"
+      // by a factor 1/2.
+      scale(_h_central_same_cross_section, 2.0/lumi_gen * 1.0/dy_photon * 1.0/dy_jet_central);
+      scale(_h_central_opp_cross_section, 2.0/lumi_gen * 1.0/dy_photon * 1.0/dy_jet_central);
+      scale(_h_forward_same_cross_section, 2.0/lumi_gen * 1.0/dy_photon * 1.0/dy_jet_forward);
+      scale(_h_forward_opp_cross_section, 2.0/lumi_gen * 1.0/dy_photon * 1.0/dy_jet_forward);
     }
  
     //@}