scholarly journals Axiogenesis from SU(2)R phase transition

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Keisuke Harigaya ◽  
Ruoquan Wang
Keyword(s):  
Parameter Space ◽  
Gauge Boson ◽  
Baryon Number ◽  
Mass Scale ◽  
Minimal Extension ◽  
Abelian Gauge ◽  
The Standard Model ◽  
Axion Decay Constant ◽  
Axion Decay ◽  
The Universe

Abstract The baryon asymmetry of the universe may be explained by rotations of the QCD axion in field space and baryon number violating processes. We consider the minimal extension of the Standard Model by a non-Abelian gauge interaction, SU(2)R, whose sphaleron process violates baryon number. Assuming that axion dark matter is also created from the axion rotation by the kinetic misalignment mechanism, the mass scale of the SU(2)R gauge boson is fixed as a function of the QCD axion decay constant, and vise versa. Significant portion of the parameter space has already been excluded by new gauge boson searches, and the high-luminocity LHC will further probe the viable parameter space.

scholarly journals Photophilic hadronic axion from heavy magnetic monopoles

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Anton V. Sokolov ◽  
Andreas Ringwald
Keyword(s):  
Globular Clusters ◽  
Proper Time ◽  
Magnetic Monopoles ◽  
Horizontal Branch Stars ◽  
Hadronic Axion ◽  
The Standard Model ◽  
Leading Term ◽  
Axion Decay Constant ◽  
Axion Decay ◽  
The Universe

Abstract We propose a model for the QCD axion which is realized through a coupling of the Peccei-Quinn scalar field to magnetically charged fermions at high energies. We show that the axion of this model solves the strong CP problem and then integrate out heavy magnetic monopoles using the Schwinger proper time method. We find that the model discussed yields axion couplings to the Standard Model which are drastically different from the ones calculated within the KSVZ/DFSZ-type models, so that large part of the corresponding parameter space can be probed by various projected experiments. Moreover, the axion we introduce is consistent with the astrophysical hints suggested both by anomalous TeV-transparency of the Universe and by excessive cooling of horizontal branch stars in globular clusters. We argue that the leading term for the cosmic axion abundance is not changed compared to the conventional pre-inflationary QCD axion case for axion decay constant fa> 1012 GeV.

scholarly journals Effective operator bases for beyond Standard Model scenarios: an EFT compendium for discoveries

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Upalaparna Banerjee ◽  
Joydeep Chakrabortty ◽  
Suraj Prakash ◽  
Shakeel Ur Rahaman ◽  
Michael Spannowsky
Keyword(s):  
Standard Model ◽  
High Energy ◽  
Beyond The Standard Model ◽  
Minimal Extension ◽  
Effective Operator ◽  
Abelian Gauge ◽  
Gauge Symmetries ◽  
Higher Dimensional ◽  
The Standard Model ◽  
Mass Dimension

Abstract It is not only conceivable but likely that the spectrum of physics beyond the Standard Model (SM) is non-degenerate. The lightest non-SM particle may reside close enough to the electroweak scale that it can be kinematically probed at high-energy experiments and on account of this, it must be included as an infrared (IR) degree of freedom (DOF) along with the SM ones. The rest of the non-SM particles are heavy enough to be directly experimentally inaccessible and can be integrated out. Now, to capture the effects of the complete theory, one must take into account the higher dimensional operators constituted of the SM DOFs and the minimal extension. This construction, BSMEFT, is in the same spirit as SMEFT but now with extra IR DOFs. Constructing a BSMEFT is in general the first step after establishing experimental evidence for a new particle. We have investigated three different scenarios where the SM is extended by additional (i) uncolored, (ii) colored particles, and (iii) abelian gauge symmetries. For each such scenario, we have included the most-anticipated and phenomenologically motivated models to demonstrate the concept of BSMEFT. In this paper, we have provided the full EFT Lagrangian for each such model up to mass dimension 6. We have also identified the CP, baryon (B), and lepton (L) number violating effective operators.

scholarly journals Flavour Anomalies in a U(1) SUSY Extension of the SM

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 191
Author(s):  
Alexander Bednyakov ◽  
Alfiia Mukhaeva
Keyword(s):  
Standard Model ◽  
Parameter Space ◽  
Gauge Boson ◽  
New Physics ◽  
Low Energy ◽  
Effective Theory ◽  
The Standard Model ◽  
Meson Mixing ◽  
Additional Anomaly ◽  
Lepton Flavour

Flavour anomalies have attracted a lot of attention over recent years as they provide unique hints for possible New Physics. Here, we consider a supersymmetric (SUSY) extension of the Standard Model (SM) with an additional anomaly-free gauge U(1) group. The key feature of our model is the particular choice of non-universal charges to the gauge boson Z′, which not only allows a relaxation of the flavour discrepancies but, contrary to previous studies, can reproduce the SM mixing matrices both in the quark and lepton sectors. We pay special attention to the latter and explicitly enumerate all parameters relevant for our calculation in the low-energy effective theory. We find regions in the parameter space that satisfy experimental constraints on meson mixing and LHC Z′ searches and can alleviate the flavour anomalies. In addition, we also discuss the predictions for lepton-flavour violating decays B+→K+μτ and B+→K+eτ.

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 Evidence of the big fix

2014 ◽  
Vol 29 (17) ◽  
pp. 1450099 ◽  
Author(s):  
Yuta Hamada ◽  
Hikaru Kawai ◽  
Kiyoharu Kawana
Keyword(s):  
Maximum Entropy Principle ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Baryon Number ◽  
Quark Masses ◽  
Atomic Nuclei ◽  
The Standard Model ◽  
Entropy Principle ◽  
Fundamental Law ◽  
The Universe

We give an evidence of the Big Fix. The theory of wormholes and multiverse suggests that the parameters of the Standard Model are fixed in such a way that the total entropy at the late stage of the universe is maximized, which we call the maximum entropy principle. In this paper, we discuss how it can be confirmed by the experimental data, and we show that it is indeed true for the Higgs vacuum expectation value vh. We assume that the baryon number is produced by the sphaleron process, and that the current quark masses, the gauge couplings and the Higgs self-coupling are fixed when we vary vh. It turns out that the existence of the atomic nuclei plays a crucial role to maximize the entropy. This is reminiscent of the anthropic principle, however it is required by the fundamental law in our case.

scholarly journals ELECTROWEAK UNIFICATION OF QUARKS AND LEPTONS IN A GAUGE GROUP SUC(3) × SU(4) × UX(1)

2012 ◽  
Vol 27 (21) ◽  
pp. 1250117 ◽  
Author(s):  
FAYYAZUDDIN
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Gauge Group ◽  
Lower Limit ◽  
Z Boson ◽  
Early Stage ◽  
Mass Scale ◽  
The Standard Model ◽  
Vector Bosons ◽  
The Universe

A model for electroweak unification of quarks and leptons, in a gauge group SUC(3) × SU(4) × UX(1) is constructed. The model requires, three generations of quarks and leptons which are replicas (mirror) of the standard quarks and leptons. The gauge group SU(4) × UX(1) is broken in such a way so as to reproduce standard model and to generate heavy masses for the vector bosons [Formula: see text], the leptoquarks and mirror fermions. It is shown lower limit on mass scale of mirror fermions is [Formula: see text], E- being the lightest mirror fermion coupled to Z boson. As the universe expands, the heavy matter is decoupled at an early stage of expansion and may be a source of dark matter. Leptoquarks in the model connect the standard model and mirror fermions. Baryon genesis in our universe implies antibaryon genesis in mirror universe.

scholarly journals Challenges for an axion explanation of the muon g − 2 measurement

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Manuel A. Buen-Abad ◽  
JiJi Fan ◽  
Matthew Reece ◽  
Chen Sun
Keyword(s):  
Decay Constant ◽  
Standard Model Prediction ◽  
New Physics ◽  
Effective Theory ◽  
General Sense ◽  
Weak Scale ◽  
Initial Application ◽  
The Standard Model ◽  
Axion Decay Constant ◽  
Axion Decay

Abstract The discrepancy between the muon g − 2 measurement and the Standard Model prediction points to new physics around or below the weak scale. It is tantalizing to consider the loop effects of a heavy axion (in the general sense, also known as an axion-like particle) coupling to leptons and photons as an explanation for this discrepancy. We provide an updated analysis of the necessary couplings, including two-loop contributions, and find that the new physics operators point to an axion decay constant on the order of 10s of GeV. This poses major problems for such an explanation, as the axion couplings to leptons and photons must be generated at low scales. We outline some possibilities for how such couplings can arise, and find that these scenarios predict new charged matter at or below the weak scale and new scalars can mix with the Higgs boson, raising numerous phenomenological challenges. These scenarios also all predict additional contributions to the muon g−2 itself, calling the initial application of the axion effective theory into question. We conclude that there is little reason to favor an axion explanation of the muon g – 2 measurement relative to other models postulating new weak-scale matter.

scholarly journals Predictive S4 flavon model with TM1 mixing and baryogenesis through leptogenesis

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Mainak Chakraborty ◽  
R. Krishnan ◽  
Ambar Ghosal
Keyword(s):  
Neutrino Mass ◽  
Parameter Space ◽  
Mass Matrix ◽  
Mass Scale ◽  
Baryon Asymmetry ◽  
Approximate Analytic Solution ◽  
Boltzmann Equations ◽  
Majorana Neutrinos ◽  
Cp Symmetry ◽  
The Universe

Abstract We use S4 discrete group to construct a neutrino flavour model which leads to T M1 mixing and is consistent with the neutrino oscillation data. Using the model’s constrained parameter space, we predict the values of Dirac C P phase and the light neutrino mass as −1 < sin δ < −0.9 and 1.7 < m1(meV) < 5.5 respectively. We thoroughly examine the usefulness of this model in explaining the observed baryon asymmetry of the Universe. Near-maximal breaking of CP symmetry (arising due to the TM1 constraint) helps us in generating adequate baryon asymmetry through leptogenesis. We study the evolution of the asymmetry (generated due to the decay of the heavy Majorana neutrinos) starting from the primordial Universe in two different ways (i)explicitly solving network of Boltzmann equations, (ii) using approximate analytic solution and we have shown the extent of their equivalence. Nearly accurate analytical fits are used thereafter to evaluate baryon asymmetry for the whole parameter space allowed by 3σ global fit of oscillation data and to impose a constraint on the yet unbounded mass scale parameter of Dirac neutrino mass matrix. Furthermore, significant contribution of N2 decay in the context of flavoured leptogenesis is also estimated.

scholarly journals An allowed window for heavy neutral leptons below the kaon mass

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Kyrylo Bondarenko ◽  
Alexey Boyarsky ◽  
Juraj Klaric ◽  
Oleksii Mikulenko ◽  
Oleg Ruchayskiy ◽  
...  
Keyword(s):  
Standard Model ◽  
Parameter Space ◽  
Big Bang ◽  
Majorana Fermions ◽  
Neutrino Masses ◽  
Beyond The Standard Model ◽  
Big Bang Nucleosynthesis ◽  
Kaon Mass ◽  
The Standard Model ◽  
The Universe

Abstract The extension of the Standard Model with two gauge-singlet Majorana fermions can simultaneously explain two beyond-the-Standard-model phenomena: neutrino masses and oscillations, as well as the origin of the matter-antimatter asymmetry in the Universe. The parameters of such a model are constrained by the neutrino oscillation data, direct accelerator searches, big bang nucleosynthesis, and requirement of successful baryogenesis. We show that their combination still leaves an allowed region in the parameter space below the kaon mass. This region can be probed by the further searches of NA62, DUNE, or SHiP experiments.

scholarly journals Lepton-mediated electroweak baryogenesis, gravitational waves and the 4τ final state at the collider

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Ke-Pan Xie
Keyword(s):  
Phase Transition ◽  
Gravitational Waves ◽  
Parameter Space ◽  
Baryon Asymmetry ◽  
Hadron Colliders ◽  
Electroweak Phase Transition ◽  
Final State ◽  
First Order ◽  
The Standard Model ◽  
The Universe

Abstract An electroweak baryogenesis (EWBG) mechanism mediated by τ lepton transport is proposed. We extend the Standard Model with a real singlet scalar S to trigger the strong first-order electroweak phase transition (SFOEWPT), and with a set of leptophilic dimension-5 operators to provide sufficient CP violating source. We demonstrate this model is able to generate the observed baryon asymmetry of the universe. This scenario is experimentally testable via either the SFOEWPT gravitational wave signals at the next-generation space-based detectors, or the pp → h* → SS → 4τ process (where h* is an off-shell Higgs) at the hadron colliders. A detailed collider simulation shows that a considerable fraction of parameter space can be probed at the HL-LHC, while almost the whole parameter space allowed by EWBG can be reached by the 27 TeV HE-LHC.

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