Two-real-scalar-singlet extension of the SM: LHC phenomenology and benchmark scenarios
- PDF / 3,900,780 Bytes
- 20 Pages / 595.276 x 790.866 pts Page_size
- 7 Downloads / 184 Views
Regular Article - Theoretical Physics
Two-real-scalar-singlet extension of the SM: LHC phenomenology and benchmark scenarios Tania Robens1,a , Tim Stefaniak2,b , Jonas Wittbrodt2,c 1 2
Ruder Boskovic Institute, Bijenicka cesta 54, 10000 Zagreb, Croatia DESY, Notkestraße 85, 22607 Hamburg, Germany
Received: 12 September 2019 / Accepted: 15 January 2020 © The Author(s) 2020
Abstract We investigate the LHC phenomenology of a model where the Standard Model (SM) scalar sector is extended by two real scalar singlets. A Z2 ⊗ Z2 discrete symmetry is imposed to reduce the number of scalar potential parameters, which is spontaneously broken by the vacuum expectation values of the singlet fields. As a result, all three neutral scalar fields mix, leading to three neutral CP-even scalar bosons, out of which one is identified with the observed Higgs boson at 125 GeV. We explore all relevant collider signatures of the three scalars in this model. Besides the single production of a scalar boson decaying directly to SM particle final states, we extensively discuss the possibility of resonant multi-scalar production. The latter includes decays of the produced scalar boson to two identical scalars (“symmetric decays”), as well as to two different scalars (“asymmetric decays”). Furthermore, we discuss the possibility of successive decays to the lightest scalar states (“cascade decays”), which lead to experimentally spectacular three- and fourHiggs final states. We provide six benchmark scenarios for detailed experimental studies of these Higgs-to-Higgs decay signatures.
1 Introduction The Large Hadron Collider (LHC) at CERN is the first experimental facility that directly probes the mechanism of electroweak symmetry breaking (EWSB), described in the Standard Model of particle physics (SM) by the Brout-EnglertHiggs mechanism [1–6]. The milestone discovery of a Higgs boson with a mass of ∼ 125 GeV in 2012 [7,8] and the ongoing measurements of its properties at the LHC (see e.g. Ref. [9]) open the door to a deeper understanding of the structure a e-mail:
[email protected]
b e-mail:
[email protected]
c e-mail:
[email protected] (corresponding author)
0123456789().: V,-vol
of EWSB. Indeed, this experimental endeavor may reveal first signs of new physics beyond the SM (BSM), as many well-motivated BSM extensions affect the phenomenology of the observed scalar particle. However, by the end of RunII of the LHC, with the full collected data of ∼ 150 fb−1 per experiment (ATLAS and CMS) still being analyzed, Higgs signal rate measurements in various production and decay channels [10–20] are so far in very good agreement with the SM predictions. Extensions of the SM by scalar singlets are among the simplest possible model beyond the SM (BSM). The most general extension of the SM by n real scalar singlet fields φi (i ∈ [1, . . . , n]) has a scalar potential of the form V (φi , ) = Vsinglets (φi , ) + VSM () ,
(1)
where Vsinglets (φi , ) = ai φi + m i j φi φ j + Ti jk φi φ j φk + λi jkl φi φ j φk φl +Ti H H φi († ) + λi
Data Loading...
