Physics Letters B 765 (2017) 265–271
Contents lists available at ScienceDirect
Physics Letters B
www.elsevier.com/locate/physletb
Fully differential Higgs pair production in association with a W boson
at next-to-next-to-leading order in QCD
Hai Tao Li
a
, Jian Wang
b,∗,1
a
ARC Centre of Excellence for Particle Physics at the Terascale, School of Physics and Astronomy, Monash University, Victoria, 3800, Australia
b
PRISMA Cluster of Excellence & Mainz Institute for Theoretical Physics, Johannes Gutenberg University, D-55099 Mainz, Germany
a r t i c l e i n f o a b s t r a c t
Article history:
Received
12 October 2016
Received
in revised form 13 December 2016
Accepted
13 December 2016
Available
online 16 December 2016
Editor:
J. Hisano
To clarify the electroweak symmetry breaking mechanism, we need to probe the Higgs self-couplings,
which can be measured in Higgs pair productions. The associated production with a vector boson is
special due to a clear tag in the final state. We perform a fully differential next-to-next-to-leading-order
calculation of the Higgs pair production in association with a W boson at hadron colliders, and present
numerical results at the 14 TeV LHC and a future 100 TeV hadron collider.
© 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
It is of high importance to precisely measure the properties of
the Higgs boson following its discovery in 2012 [1,2]. Present anal-
yses
show that it is a spin-0 and CP-even particle with a mass of
125 GeV [3]. Its couplings with massive vector bosons have been
measured to agree with the standard model (SM) expectations
[4,5]. The couplings with heavy fermions, such as the top quark,
the bottom quark and the τ -lepton, have also been determined in
accordance with the SM [4,5]. The still unconfirmed properties are
its self-couplings, which are crucial to clarify the electroweak sym-
metry
breaking mechanism. These couplings may be tested with
the upcoming collision data at the LHC [6–16] or a future 100 TeV
hadron collider [17–22].
Though
it is possible to get some indications on the Higgs self-
couplings
from the virtual effects [23], the direct detection plays
an indispensable role in probing these couplings. The triple Higgs
coupling can be measured by studying the Higgs pair productions
at hadron colliders. The dominant production channel is the gluon-
gluon
fusion which involves a top-quark loop. The other channels,
including the vector boson fusion, the vector boson associated pro-
duction
and the top quark pair associated production, have rela-
tively
smaller cross sections. One reason is that the phase space
integration is smaller with more final-state particles. However, the
*
Corresponding author.
E-mail
addresses: haitao.li@monash.edu (H.T. Li), jian.wang@uni-mainz.de,
j.wang@tum.de (J. Wang).
1
Present address: Physik Department T31, Technische Universität München,
James-Franck-Straße 1, D-85748 Garching, Germany.
additional particles in the final state provide more handles on the
signal so that the backgrounds can be significantly suppressed. Ac-
tually,
the different channels have different characteristics, thus
are complementary to each other and deserve discussion on the
same footing. In this work, we focus on the vector boson asso-
ciated
production channel, as shown in Fig. 1(a). This channel is
special for several reasons. Since there is an associated vector bo-
son
that can serve as a characteristic tag, one can select the events
with the Higgs boson decaying to bottom quarks. In this case, all
the involved Higgs couplings are not loop-induced, avoiding the
unknown effects of virtual heavy particles. Meanwhile, benefiting
from the large branching fraction of the Higgs decay to bottom
quarks, the cross section of this channel is comparable to that of
the gluon-gluon fusion production and decay to γγb
¯
b [24]. More-
over,
it depends on the value of the Higgs self-coupling in a dif-
ferent
way from the gluon-gluon fusion channel. As a result, it is
very sensitive to the Higgs self-coupling that is larger than the SM
value [24,25].
The
precise theoretical predictions are crucial for a proper in-
terpretation
of the experimental data. The total cross section of the
vector boson associated production has been calculated up to next-
to-next-to-leading
order (NNLO) in analogy to the Drell–Yan pro-
duction
[9]. However, in practice, experimental cuts are imposed
on the final state. It is not clear whether the NNLO corrections are
the same over the full phase space. Our aim in this work is to
provide a fully differential NNLO calculation of the Higgs pair pro-
duction
in association with a W boson at hadron colliders. This
precise theoretical prediction can be used as a basic input when
analyzing the events in the future.
http://dx.doi.org/10.1016/j.physletb.2016.12.030
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
.