scholarly journals Conformal Complex Scalar Singlet Extensions of the Standard Model: Symmetry Breaking Patterns and Phenomenology

2017 ◽  
Author(s):  
Zhi Wang ◽  
Frederick Sage ◽  
Tom Steele ◽  
Robert Mann ◽  
Tanvir Hanif
Keyword(s):  
Standard Model ◽  
Symmetry Breaking ◽  
Complex Scalar ◽  
The Standard Model ◽  
Scalar Singlet

scholarly journals Chiral anomaly in SU(2)R-axion inflation and the new prediction for particle cosmology

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Azadeh Maleknejad
Keyword(s):  
Standard Model ◽  
Symmetry Breaking ◽  
Particle Physics ◽  
Cosmological Parameters ◽  
Chiral Anomaly ◽  
Dark Matter Candidate ◽  
Neutrino Sector ◽  
Matter Creation ◽  
The Standard Model ◽  
Non Gaussian

Abstract Upon embedding the axion-inflation in the minimal left-right symmetric gauge extension of the SM with gauge group SU(2)L × SU(2)R × U(1)B−L, [1] proposed a new particle physics model for inflation. In this work, we present a more detailed analysis. As a compelling consequence, this setup provides a new mechanism for simultaneous baryogenesis and right-handed neutrino creation by the chiral anomaly of WR in inflation. The lightest right-handed neutrino is the dark matter candidate. This setup has two unknown fundamental scales, i.e., the scale of inflation and left-right symmetry breaking SU(2)R × U(1)B−L→ U(1)Y. Sufficient matter creation demands the left-right symmetry breaking scale happens shortly after the end of inflation. Interestingly, it prefers left-right symmetry breaking scales above 1010 GeV, which is in the range suggested by the non-supersymmetric SO(10) Grand Unified Theory with an intermediate left-right symmetry scale. Although WR gauge field generates equal amounts of right-handed baryons and leptons in inflation, i.e. B − L = 0, in the Standard Model sub-sector B − LSM ≠ 0. A key aspect of this setup is that SU(2)R sphalerons are never in equilibrium, and the primordial B − LSM is conserved by the Standard Model interactions. This setup yields a deep connection between CP violation in physics of inflation and matter creation (visible and dark); hence it can naturally explain the observed coincidences among cosmological parameters, i.e., ηB ≃ 0.3Pζ and ΩDM ≃ 5ΩB. The new mechanism does not rely on the largeness of the unconstrained CP-violating phases in the neutrino sector nor fine-tuned masses for the heaviest right-handed neutrinos. The SU(2)R-axion inflation comes with a cosmological smoking gun; chiral, non-Gaussian, and blue-tilted gravitational wave background, which can be probed by future CMB missions and laser interferometer detectors.

scholarly journals Dark moments for the Standard Model?

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Thomas G. Rizzo
Keyword(s):  
Standard Model ◽  
Magnetic Dipole ◽  
Parameter Space ◽  
Gauge Coupling ◽  
Large Mass ◽  
Mass Scale ◽  
Complex Scalar ◽  
Quantum Numbers ◽  
The Standard Model ◽  
Model Setup

Abstract If dark matter (DM) interacts with the Standard Model (SM) via the kinetic mixing (KM) portal, it necessitates the existence of portal matter (PM) particles which carry both dark and SM quantum numbers that will appear in vacuum polarization-like loop graphs. In addition to the familiar ∼ eϵQ strength, QED-like interaction for the dark photon (DP), in some setups different loop graphs of these PM states can also induce other coupling structures for the SM fermions that may come to dominate in at least some regions of parameter space regions and which can take the form of ‘dark’ moments, e.g., magnetic dipole-type interactions in the IR, associated with a large mass scale, Λ. In this paper, motivated by a simple toy model, we perform a phenomenological investigation of a possible loop-induced dark magnetic dipole moment for SM fermions, in particular, for the electron. We show that at the phenomenological level such a scenario can not only be made compatible with existing experimental constraints for a significant range of correlated values for Λ and the dark U(1)D gauge coupling, gD, but can also lead to quantitatively different signatures once the DP is discovered. In this setup, assuming complex scalar DM to satisfy CMB constraints, parameter space regions where the DP decays invisibly are found to be somewhat preferred if PM mass limits from direct searches at the LHC and our toy model setup are all taken seriously. High precision searches for, or measurements of, the e+e− → γ + DP process at Belle II are shown to provide some of the strongest future constraints on this scenario.

scholarly journals Exploration of Extended Higgs Sectors with Run-2 Proton–Proton Collision Data at the LHC

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2144
Author(s):  
Arnaud Ferrari ◽  
Nikolaos Rompotis
Keyword(s):  
Standard Model ◽  
Higgs Sector ◽  
Scalar Fields ◽  
Higgs Bosons ◽  
Proton Collision ◽  
Complex Scalar ◽  
Proton Proton ◽  
The Standard Model ◽  
Extended Higgs Sectors ◽  
Proton Proton Collision

One doublet of complex scalar fields is the minimal content of the Higgs sector in order to achieve spontaneous electroweak symmetry breaking and, in turn, to generate the masses of fundamental particles in the Standard Model. However, several theories beyond the Standard Model predict a nonminimal Higgs sector and introduce additional singlets, doublets or even higher-order weak isospin representations, thereby yielding additional Higgs bosons. With its high proton–proton collision energy (13 TeV during Run-2), the Large Hadron Collider opens a new window towards the exploration of extended Higgs sectors. This review article summarises the current state-of-the-art experimental results recently obtained in searches for new neutral and charged Higgs bosons with a partial or full Run-2 dataset.

scholarly journals Constraining extended scalar sectors at the LHC and beyond

2018 ◽  
Vol 33 (10n11) ◽  
pp. 1830007 ◽  
Author(s):  
Agnieszka Ilnicka ◽  
Tania Robens ◽  
Tim Stefaniak
Keyword(s):  
Dark Matter ◽  
Higgs Boson ◽  
Standard Model ◽  
Parameter Space ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
Doublet Model ◽  
Inert Doublet Model ◽  
Scalar Sector ◽  
Scalar Singlet

We give a brief overview of beyond the Standard Model (BSM) theories with an extended scalar sector and their phenomenological status in the light of recent experimental results. We discuss the relevant theoretical and experimental constraints, and show their impact on the allowed parameter space of two specific models: the real scalar singlet extension of the Standard Model (SM) and the Inert Doublet Model. We emphasize the importance of the LHC measurements, both the direct searches for additional scalar bosons, as well as the precise measurements of properties of the Higgs boson of mass 125 GeV. We show the complementarity of these measurements to electroweak and dark matter observables.

Flavons and LFV decays and productions of pseudoscalar mesons

2019 ◽  
Vol 34 (35) ◽  
pp. 1950288
Author(s):  
Tian-Qi Li ◽  
Chong-Xing Yue
Keyword(s):  
Standard Model ◽  
Symmetry Breaking ◽  
Flavor Symmetry ◽  
Lepton Flavor ◽  
Flavor Changing ◽  
Pseudoscalar Mesons ◽  
The Standard Model

Flavons are the dynamic agent of flavor symmetry breaking and have flavor changing couplings to the Standard Model (SM) fermions. We consider their contributions to the lepton flavor violating (LFV) decays [Formula: see text] and [Formula: see text] with [Formula: see text], [Formula: see text] or [Formula: see text] and [Formula: see text] in the simplest flavon model without Higgs-flavon mixing. We find that flavons can produce significant contributions to some of these LFV decay processes.

Sign in / Sign up

Export Citation Format

Share Document