diff --git a/benchmarks/barrel_ecal/scripts/emcal_barrel_pions_analysis.cxx b/benchmarks/barrel_ecal/scripts/emcal_barrel_pions_analysis.cxx
index dc7fe0fb6a701c2dcc6e99cb6f6dff9a8efbc7c2..a49ca514072454b4d6ccc1fd6c960276cc786966 100644
--- a/benchmarks/barrel_ecal/scripts/emcal_barrel_pions_analysis.cxx
+++ b/benchmarks/barrel_ecal/scripts/emcal_barrel_pions_analysis.cxx
@@ -127,7 +127,7 @@ void emcal_barrel_pions_analysis(const char* input_fname = "sim_output/sim_emcal
               ;
   // Set sampling Fraction, ideally this will be taken from a json file 
   auto svec = d1.Mean<double>("fsam");
-  for (auto ele : svec){cout << ele << endl;}
+  for (auto &ele : svec){cout << ele << endl;}
 
   auto d2 = d1.Define("dE",     eResol,     {"Esim","Ethr"})
               .Define("dE_rel", eResol_rel, {"Esim","Ethr"})