diff --git a/include/util.h b/include/util.h
index 9d66841be643cd72d574e76d4796fbe6cfb70b56..3460bbc237d9ecf640311c01659799fbf3a4dc53 100644
--- a/include/util.h
+++ b/include/util.h
@@ -88,7 +88,7 @@ namespace util {
       const double py = 0.;
       const double pz = 0.;
       const double mass = 0.;*/
-      return ROOT::Math::PxPyPzMVector{part.p.x, part.p.y, part.p.z, part.mass};
+      return ROOT::Math::PxPyPzMVector{part.p.x, part.p.y, part.p.z, part.mass()};
     });
     return momenta;
   }