Physics Letters B 765 (2017) 300–306
Contents lists available at ScienceDirect
Physics Letters B
www.elsevier.com/locate/physletb
Exploring the Inert Doublet Model through the dijet plus missing
transverse energy channel at the LHC
P. Poulose
a,∗
, Shibananda Sahoo
a
, K. Sridhar
b
a
Department of Physics, Indian Institute of Technology Guwahati, Assam 781039, India
b
Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India
a r t i c l e i n f o a b s t r a c t
Article history:
Received
20 April 2016
Received
in revised form 3 December 2016
Accepted
8 December 2016
Available
online 14 December 2016
Editor:
G.F. Giudice
In this study of the Inert Doublet Model (IDM), we propose that the dijet + missing transverse energy
channel at the Large Hadron Collider (LHC) will be an effective way of searching for the scalar particles
of the IDM. This channel receives contributions from gauge boson fusion, and t-channel production,
along with contributions from H
+
associated production. We perform the analysis including study of
the Standard Model (SM) background with assumed systematic uncertainty, and optimise the selection
criteria employing suitable cuts on the kinematic variables to maximise the signal significance. We find
that with high luminosity option of the LHC, this channel has the potential to probe the IDM in the mass
range of up to about 400 GeV, which is not accessible through other leptonic channels. In a scenario with
light dark matter of mass about 65 GeV, charged Higgs in the mass range of around 200 GeV provides
the best possibility with a signal significance of about 2σ at an integrated luminosity of about 3000 fb
−1
.
© 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license
(http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP
3
.
1. Introduction
The discovery of Higgs boson by the ATLAS and CMS collab-
orations
of the LHC [1,2] has definitely put the spotlight of par-
ticle
physics research on Higgs phenomenology. While all mea-
surements
so far indicate that the new particle is indeed a Higgs
boson, compatible with that predicted by the Standard Model (SM)
of particle physics, detailed questions about the exact nature of
the Higgs potential and the coupling of the Higgs particle to other
SM particles need to be investigated. This information, along with
the popular reasoning that the SM Higgs mechanism is only an
effective description to understand Electroweak Symmetry Break-
ing
(EWSB), of a more fundamental high-energy theory has led
researchers to study the implication of many variant models. It
is believed that the Standard Higgs mechanism with only one
physical scalar is too minimalistic, and in reality, there could be
more than one Higgs field sharing the responsibility of EWSB. Such
multi-Higgs models are also motivated by other drawbacks of the
SM. For example, low-energy supersymmetric model (Minimal Su-
persymmetric
Standard Model – MSSM) proposed as a remedy to
*
Corresponding author.
E-mail
addresses: poulose@iitg.ernet.in (P. Poulose), shibananda@iitg.ernet.in
(S. Sahoo),
sridhar@theory.tifr.res.in (K. Sridhar).
the hierarchy problem requires two doublet Higgs fields, resulting
in the physical spectrum with five more scalars, three of which
are neutral. The two-Higgs Doublet Model (2HDM) without super-
symmetry
has also been a popular theoretical option beyond the
minimal Higgs mechanism proposed by the SM. The issue of dark
matter, required by astrophysical observations but for which we
lack a suitable candidate in the SM, is another important reason to
attempt to go beyond the SM and, in these attempts, it is often the
minimalism of the scalar sector of the SM that is sacrificed.
The
2HDM with one of the doublet fields not having any direct
(at the level of the Lagrangian) interaction with the SM particles,
except the gauge particles, is a promising candidate model in this
regard. This is achieved by the imposition of a Z
2
symmetry un-
der
which one of the doublets is odd, while all other fields are
even. Such an Inert Doublet Model (IDM) [3] would have the Higgs
phenomenology, quite different from that of the SM as well as the
MSSM or the usual 2HDM scenarios. For example, in the physical
Higgs boson sector, all neutral scalars except one are odd under
the Z
2
symmetry and are, therefore, always produced in pairs. This
also means that the lightest of these cannot decay, and thus could
be a candidate for dark matter. Adding a Z
2
-odd right-handed
neutrino to this model can also generate small neutrino masses
radiatively [4], and to generate leptogenesis [5], ideas which are
followed up in further studies [6–14]. The model is shown to be
helpful in explaining the LEP-paradox [15–17], and could also gen-
http://dx.doi.org/10.1016/j.physletb.2016.12.022
0370-2693/
© 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by
SCOAP
3
.