Comparison of $H\to\ell\bar{\ell}\gamma$ and $H\to\gamma\,Z, Z\to\ell\bar{\ell}$ including the ATLAS cuts

Understand

A precise comparison is made between the Dalitz decay $H\to\ell\bar{\ell}\gamma$ and the two body decay $H\to\gamma Z,Z\to\ell\bar{\ell}$ for electrons and for muons including experimental cuts appropriate for the ATLAS detector.

• The widths for these two processes differ by 8% for electrons and 3% for muons.
• Given that there remain QCD radiative corrections of this order that are not included, this suggests that the isolation of the Dalitz decay will be challenging.