Axial-vector transition form factors and e+e− → f1π+π−
Axial-vector transition form factors and e+e− → f1π+π−
We study the transition form factors (TFFs) of axial-vector mesons in the context of currently available experimental data, including new constraints from $e^+ e^- \to f_1(1285) \pi^+ \pi^-$ that imply stringent limits on the high-energy behavior and, for the first time, allow us to provide an unambiguous determination of the …