Higgs–photon resonances

Bogdan A. Dobrescu; Patrick J. Fox; John Kearney

doi:10.1140/epjc/s10052-017-5276-9

EPJ

a
b
c
d
e
ap
st
h
plus
ds
pv
ti
qt
am
n

2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2017) 77: 704
https://doi.org/10.1140/epjc/s10052-017-5276-9

Regular Article - Theoretical Physics

Higgs–photon resonances

Bogdan A. Dobrescu, Patrick J. Fox^* and John Kearney

Theoretical Physics Department, Fermilab, Batavia, IL, 60510, USA

^* e-mail: pjfox@fnal.gov

Received: 2 June 2017
Accepted: 2 October 2017
Published online: 24 October 2017

Abstract

We study models that produce a Higgs boson plus photon ( $h^0\gamma$ ) resonance at the LHC. When the resonance is a $$Z'$$ boson, decays to $h^0\gamma$ occur at one loop. If the $$Z'$$ boson couples at tree level to quarks, then the $h^0\gamma$ branching fraction is typically of order $10^{-5}$ or smaller. Nevertheless, there are models that would allow the observation of $Z'\rightarrow \,h^0\gamma$ at $\sqrt{s}=13$ TeV with a cross section times branching fraction larger than 1 fb for a $$Z'$$ mass in the 200–450 GeV range, and larger than 0.1 fb for a mass up to 800 GeV. The one-loop decay of the $$Z'$$ into lepton pairs competes with $h^0\gamma$ , even if the $$Z'$$ couplings to leptons vanish at tree level. We also present a model in which a $$Z'$$ boson decays into a Higgs boson and a pair of collimated photons, mimicking an $h^0\gamma$ resonance. In this model, the $h^0\gamma$ resonance search would be the discovery mode for a $$Z'$$ as heavy as 2 TeV. When the resonance is a scalar, although decay to $h^0\gamma$ is forbidden by angular momentum conservation, the $$h^0$$ plus collimated photons channel is allowed. We comment on prospects of observing an $h^0\gamma$ resonance through different Higgs decays, on constraints from related searches, and on models where $$h^0$$ is replaced by a nonstandard Higgs boson.