diff --git a/include/util.h b/include/util.h
index eebf80d5631147d619ddcb321f3ded6574e4a2a2..f9e5685b24de601dcd510e36ee44c19f30dcb7b8 100644
--- a/include/util.h
+++ b/include/util.h
@@ -83,9 +83,10 @@ namespace util {
     std::vector<ROOT::Math::PxPyPzMVector> momenta{parts.size()};
     // transform our raw tracker info into proper 4-momenta
     std::transform(parts.begin(), parts.end(), momenta.begin(), [](const auto& part) {
-      const double px = part.p.x();
-      const double py = part.p.y();
-      const double pz = part.p.z();
+      eic::VectorXYZ p = part.p;
+      const double px = 0.;
+      const double py = 0.;
+      const double pz = 0.;
       const double mass = 0.;
       return ROOT::Math::PxPyPzMVector{px, py, pz, mass};
     });