diff --git a/src/ampform_dpd/io.py b/src/ampform_dpd/io.py
index 5fce8fc9..27d86958 100644
--- a/src/ampform_dpd/io.py
+++ b/src/ampform_dpd/io.py
@@ -102,7 +102,10 @@ def render_arrow(node: IsobarNode) -> str:
     to = render_arrow(obj)
     child1 = aslatex(obj.child1, **kwargs)
     child2 = aslatex(obj.child2, **kwargs)
-    return Rf"{parent} {to} {child1} {child2}"
+    latex = Rf"{parent} {to} {child1} {child2}"
+    if isinstance(obj.parent, State):
+        return latex
+    return Rf"\left({latex}\right)"
 
 
 @aslatex.register(ThreeBodyDecay)