Prog. Theor. Exp. Phys. 2015, 051B02 (6 pages)
DOI: 10.1093/ptep/ptv071
Letter
LHC Run-I constraint on the mass of doubly
charged Higgs bosons in the same-sign
diboson decay scenario
Shinya Kanemura
1
, Mariko Kikuchi
1
, Kei Yagyu
2
and Hiroshi Yokoya
1,∗
1
Department of Physics, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan
2
School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ, UK
∗
E-mail: hyokoya@sci.u-toyama.ac.jp, kanemu@sci.u-toyama.ac.jp, kikuchi@jodo.sci.u-toyama.ac.jp,
K.Yagyu@soton.ac.uk
Received March 7, 2015; Revised April 8, 2015; Accepted April 19, 2015; Published May 22, 2015
...............................................................................
In this letter, we study the latest bound on the mass of doubly charged Higgs bosons, H
±±
,
assuming that they dominantly decay into a diboson. The new bound is obtained by comparing
the inclusive searches by the ATLAS Collaboration [ATLAS Collaboration, J. High Energy Phys.
1503, 041 (2015)] for events with a same-sign dilepton using t he latest 20.3 fb
−1
data at t he Large
Hadron Collider 8 TeV run with a theoretical prediction based on the Higgs triplet model with
next-to-leading order QCD corrections. We find that the lower mass bound on H
±±
is about
84 GeV.
...............................................................................
Subject Index
B40, B53, B54, B62, B65
1. Introduction Recently, the ATLAS Collaboration released new results of inclusive searches
for events with a same-sign dilepton by using the 20.3 fb
−1
data at the 8 TeV run of the Large Hadron
Collider (LHC) [1]. They improved on the previous results based on the 4.7 fb
−1
data at the 7 TeV
run [2]. From non-observation of any excess from the standard model (SM) background, upper lim-
its at the 95% confidence level (CL) on the fiducial cross section have been obtained for inclusive
production of the same-sign dilepton from the non-SM contribution.
One of the most interesting applications of these results is to obtain a constraint on the parameter
space for physics related to doubly charged Higgs bosons H
±±
. In various exotic models beyond
the SM, H
±±
are predicted to exist, e.g., in the left–right symmetric model [3–5], in models with
the type-II seesaw mechanism [6–10], and in neutrino mass models via quantum effects [11–16].
In this letter, we focus on H
±±
in the Higgs triplet model (HTM) [6–10], where the Higgs sector
is composed of an isospin doublet Higgs field with the hypercharge Y = 1/2 and a triplet field with
Y = 1. In the HTM, two decay modes are allowed for H
±±
, i.e., decays into the same-sign dilepton
and the same-sign diboson [17,18].
1
If the same-sign dilepton decay is dominant, the most stringent
lower limit on the mass of H
±±
(m
H
±±
) has been obtained to be about 550 GeV [1] at the LHC.
2
1
If H
±±
are heavier than singly charged scalar bosons H
±
, H
±±
can also decay into H
±
W
±
[17–20].
2
An earlier study using the 7 TeV data has also been performed by the CMS Collaboration [21].
© The Author(s) 2015. Published by Oxford University Press on behalf of the Physical Society of Japan.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/),
which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
Funded by SCOAP
3