PWGEM/Dilepton: update a filter task (#7413)

PWGEM/Dilepton/TableProducer/filterDielectronEvent.cxx

@@ -72,7 +72,8 @@ struct filterDielectronEvent {
   Configurable<int> min_ncluster_tpc{"min_ncluster_tpc", 10, "min ncluster tpc"};
   Configurable<int> mincrossedrows{"mincrossedrows", 70, "min. crossed rows"};
   Configurable<float> min_tpc_cr_findable_ratio{"min_tpc_cr_findable_ratio", 0.8, "min. TPC Ncr/Nf ratio"};
-  Configurable<float> max_mean_its_cluster_size{"max_mean_its_cluster_size", 16.f, "max. <ITS cluster size> x cos(lambda)"}; // this is to suppress random combination. default 4 + 1 for skimming.
+  Configurable<float> max_mean_its_cluster_size{"max_mean_its_cluster_size", 16.f, "max. <ITS cluster size> x cos(lambda)"};
+  Configurable<float> max_p_for_its_cluster_size{"max_p_for_its_cluster_size", 0.2, "its cluster size cut is applied below this track momentum"};
   Configurable<int> minitsncls{"minitsncls", 4, "min. number of ITS clusters"};
   Configurable<float> maxchi2tpc{"maxchi2tpc", 5.0, "max. chi2/NclsTPC"};
   Configurable<float> maxchi2its{"maxchi2its", 6.0, "max. chi2/NclsITS"};
@@ -229,7 +230,7 @@ struct filterDielectronEvent {
       }
       total_cluster_size += cluster_size_per_layer;
     }
-    if (static_cast<float>(total_cluster_size) / static_cast<float>(nl) * std::cos(std::atan(track.tgl())) > max_mean_its_cluster_size) {
+    if (static_cast<float>(total_cluster_size) / static_cast<float>(nl) * std::cos(std::atan(track.tgl())) > max_mean_its_cluster_size && track.p() < max_p_for_its_cluster_size) {
       return false;
     }