2017/04/30 by Tao Han, Xing Wang
Physics and Astronomy · #Boson #Electroweak interaction #Fermion #Higgs boson #Large Hadron Collider #Observable #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #Quantum and Classical Electrodynamics #Radiative transfer #Standard Model (mathematical formulation) #Yukawa potential #hep-ph
paper · pdf · doi:10.1007/jhep10(2017)036
published as JHEP 1710 (2017) 036 · 23 pages, 6 figures, 6 tables; Minor corrections, references updated, version published in JHEP
openalex created_date 2017/05/05 · openalex publication_date 2017/10/01 · arxiv created 2017/10/12 · arxiv updated 2017/10/13 · openalex updated_date 2026/08/05
We revisit the radiative decays of the Higgs boson to a fermion pair h→ ffγ where f denotes a fermion in the Standard Model (SM). We include the chirality-flipping diagrams via the Yukawa couplings at the order O(yf2α ) , the chirality-conserving contributions via the top-quark loops of the order O(yt2α3) , and the electroweak loops at the order O(α4) . The QED correction is about Qf2× O(1%) and contributes to the running of fermion masses at a similar level, which should be taken into account for future precision Higgs physics. The chirality-conserving electroweak-loop processes are interesting from the observational point of view. First, the branching fraction of the radiative decay h→μ + μ −γ is about a half of that of h→μ + μ −,and that of h→e + e − γ is more than four orders of magnitude larger than that of h → e + e −, both of which reach about 10−4. The branching fraction of h → τ + τ −γ is of the order 10−3. All the leptonic radiative decays are potentially observable at the LHC Run 2 or the HL-LHC. The kinematic distributions for the photon energy or the fermion pair invariant mass provide non-ambiguous discrimination for the underlying mechanisms of the Higgs radiative decay. We also study the process h→ ccγ and evaluate the observability at the LHC. We find it potentially comparable to the other related studies and better than the h → J/ψ γ channel in constraining the charm-Yukawa coupling.