diff --git a/pyproject.toml b/pyproject.toml
index 0f66f71..d9ea530 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -28,6 +28,7 @@ dependencies = [
     "pyyaml>=5.3.1",
     "scipy>=1.6.0",
     "requests>=2.25.0",
+    "mplhep", 
 ]
 
 [project.urls]