Higgs decay into a lepton pair and a photon: a roadmap to $\mathbf{H}\to \mathbf{Z}\gamma$ discovery and probes of new physics

Abstract

The decay $H\to {\ell }^{+}{\ell }^{-}\gamma$, $\ell =e,\mu$, receives contributions from $H\to Z[\to {\ell }^{+}{\ell }^{-}]\gamma$ and a non-resonant contribution, both of which are loop-induced. We describe how one can separate these sub-processes in a gauge-independent way, define the decay rate $\Gamma (H\to Z\gamma )$, and extract the latter from differential $H\to {\ell }^{+}{\ell }^{-}\gamma$ branching ratios. For $\ell =\mu$ also the tree decay rate, which is driven by the muon Yukawa coupling, is important. We propose kinematic cuts optimized to separate the three contributions, paving the way to the milestones (i) discovery of $H\to Z\gamma$, (ii) discovery of $H\to {\mu }^{+}{\mu }^{-}{\gamma |}_{\mathrm{tree}}$, and (iii) quantification of new physics in both the effective $H$-$Z$-$\gamma$ and non-resonant $H$-${\ell }^{+}$-${\ell }^{-}$-$\gamma$ couplings.

arXiv comment15 pages, 6 figures; v2: Few typos corrected, preprint number added, acknowledgements extended

References in corpus (10)

• Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm
• New Developments in FeynCalc 9.0
• FeynCalc 9.3: New features and improvements
• Higgs Boson Production and Decay: Dalitz Sector
• Radiative Higgs Boson Decays H -> f fbar gamma
• Calculation of the decay ${\bm H\bm\to\bm e\bar{\bm e}\bm\ga}$
• Higgs decay into a lepton pair and a photon revisited
• Evidence for Higgs boson decays to a low-mass dilepton system and a photon in pp collisions at $\sqrt{s}=$ 13 TeV with the ATLAS detector
• Radiative Decays of the Higgs Boson to a Pair of Fermions
• Discovering the $h\to Z\gamma$ Decay in $t\bar{t}$ Associated Production

Cited by in corpus (4)

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• Higgs-Boson Decays: Updates
• One-loop formulas for $H\to Z{\nu }_l{\bar{\nu }}_l$ for $l=e,\mu ,\tau$ in 't Hooft-Veltman gauge