scholarly journals Probing degenerate heavy Higgs bosons in NMSSM with vector-like particles

2017 ◽  
Vol 32 (33) ◽  
pp. 1745005
Author(s):  
Fei Wang ◽  
Wenyu Wang ◽  
Lei Wu ◽  
Jin Min Yang ◽  
Mengchao Zhang

In this work, we investigate the degenerate heavy Higgs bosons in the Next-to-Minimal Supersymmetric Standard Model (NMSSM) by introducing vector-like particles. Such an extension is well motivated from the top-down view since some grand unified theories usually predict the existence of singlet scalars and vector-like particles at weak scale. Under the constraints from the Large Hadron Collider (LHC) and dark matter experiments, we find that (1) the null results of searching for high mass resonances have tightly constrained the parameter space; (2) two degenerate heavy singlet Higgs bosons [Formula: see text] and [Formula: see text] can sizably decay to [Formula: see text] invisibly. Therefore, search for the monojet events through the process [Formula: see text] may further test our scenario at the future LHC.

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Isabell Engeln ◽  
Pedro Ferreira ◽  
M. Margarete Mühlleitner ◽  
Rui Santos ◽  
Jonas Wittbrodt

Abstract We discuss the dark phases of the Next-to-2-Higgs Doublet model. The model is an extension of the Standard Model with an extra doublet and an extra singlet that has four distinct CP-conserving phases, three of which provide dark matter candidates. We discuss in detail the vacuum structure of the different phases and the issue of stability at tree-level of each phase. Taking into account the most relevant experimental and theoretical constraints, we found that there are combinations of measurements at the Large Hadron Collider that could single out a specific phase. The measurement of h125 → γγ together with the discovery of a new scalar with specific rates to τ+τ− or γγ could exclude some phases and point to a specific phase.


LEP data constrain severely many proposed extensions of the Standard Model. These include: massive neutrinos, which are now largely excluded as candidates for the dark matter of the Universe; supersymmetric particles, the lightest of which would still constitute detectable dark matter; technicolour, of which many favoured versions are now excluded by precision electroweak measurements; and grand unified theories, of which LEP data favour supersymmetric versions.


2018 ◽  
Vol 33 (03) ◽  
pp. 1850024 ◽  
Author(s):  
Ernest Ma ◽  
Diego Restrepo ◽  
Óscar Zapata

The well-known leptonic U(1) symmetry of the Standard Model (SM) of quarks and leptons is extended to include a number of new fermions and scalars. The resulting theory has an invisible QCD axion (thereby solving the strong CP problem), a candidate for weak-scale dark matter (DM), as well as radiative neutrino masses. A possible key connection is a color-triplet scalar, which may be produced and detected at the Large Hadron Collider.


2016 ◽  
Vol 31 (27) ◽  
pp. 1650163 ◽  
Author(s):  
Ernest Ma ◽  
Nicholas Pollard ◽  
Oleg Popov ◽  
Mohammadreza Zakeri

We propose an extension of the Standard Model of quarks and leptons to include gauge B–L symmetry with an exotic array of neutral fermion singlets for anomaly cancellation. With the addition of suitable scalars also transforming under U(1)[Formula: see text], this becomes a model of radiative seesaw neutrino mass with possible multipartite dark matter. If leptoquark fermions are added, necessarily also transforming under U(1)[Formula: see text], the diphoton excess at 750 GeV, recently observed at the Large Hadron Collider, may also be explained.


2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Andreas Papaefstathiou ◽  
Tania Robens ◽  
Gilberto Tetlalmatzi-Xolocotzi

Abstract We investigate the production of three Higgs bosons in the Two Real Singlet extension of the Standard Model, where the scalar sector is augmented by two additional real scalar fields which are singlets under the Standard Model gauge group. The model contains three neutral CP-even scalars, allowing for resonant production and asymmetric decay chains. We focus on the signature pp → h3→ h1h2→ h1h1h1, where we identify h3 as the heaviest scalar state, h2 as the second heaviest and the lightest, h1, as the Standard Model-like Higgs boson discovered by the Large Hadron Collider experiments. The dominant final state occurs when all three Higgs bosons decay to bottom-anti-bottom quark pairs, h1→$$ b\overline{b} $$ b b ¯ , leading to 6 b-jets. Taking into account all current theoretical and experimental constraints, we determine the discovery prospects for this channel in future runs of the Large Hadron Collider, as well as in the high-luminosity phase.


2021 ◽  
Vol 81 (12) ◽  
Author(s):  
B. C. Allanach ◽  
J. M. Butterworth ◽  
Tyler Corbett

AbstractWe examine current Large Hadron Collider constraints on some simple $$Z^\prime $$ Z ′ models that significantly improve on Standard Model fits to $$b\rightarrow s \mu ^+\mu ^-$$ b → s μ + μ - transition data. The models that we consider are the ‘third family baryon number minus second family lepton number’ ($${B_3-L_2}$$ B 3 - L 2 ) model and the ‘third family hypercharge’ model and variants. The constraints are applied on parameter regions of each model that fit the $$b\rightarrow s \mu ^+\mu ^-$$ b → s μ + μ - transition data and come from high-mass Drell–Yan di-muons and measurements of Standard Model processes. This latter set of observables place particularly strong bounds upon the parameter space of the $${B_3-L_2}$$ B 3 - L 2 model when the mass of the $$Z^\prime $$ Z ′ boson is less than 300 GeV.


Author(s):  
Michael E. Peskin

This chapter discusses the Higgs boson, the spin-0 particle in the Standard Model most closely associated with its spontaneous symmetry breaking. It gives the predictions of the Standard Model for the production and decay of Higgs bosons. It describes the experiments at the Large Hadron Collider that test these predictions.


Author(s):  
John Ellis

The Standard Model of particle physics agrees very well with experiment, but many important questions remain unanswered, among them are the following. What is the origin of particle masses and are they due to a Higgs boson? How does one understand the number of species of matter particles and how do they mix? What is the origin of the difference between matter and antimatter, and is it related to the origin of the matter in the Universe? What is the nature of the astrophysical dark matter? How does one unify the fundamental interactions? How does one quantize gravity? In this article, I introduce these questions and discuss how they may be addressed by experiments at the Large Hadron Collider, with particular attention to the search for the Higgs boson and supersymmetry.


Sign in / Sign up

Export Citation Format

Share Document