scholarly journals Challenges for a QCD axion at the 10 MeV scale

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Jia Liu ◽  
Navin McGinnis ◽  
Carlos E. M. Wagner ◽  
Xiao-Ping Wang
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Multiple Sources ◽  
Standard Model Extension ◽  
Mixing Angles ◽  
Quark Masses ◽  
Model Extension ◽  
The One

Abstract We report on an interesting realization of the QCD axion, with mass in the range $$ \mathcal{O} $$ O (10) MeV. It has previously been shown that although this scenario is stringently constrained from multiple sources, the model remains viable for a range of parameters that leads to an explanation of the Atomki experiment anomaly. In this article we study in more detail the additional constraints proceeding from recent low energy experiments and study the compatibility of the allowed parameter space with the one leading to consistency of the most recent measurements of the electron anomalous magnetic moment and the fine structure constant. We further provide an ultraviolet completion of this axion variant and show the conditions under which it may lead to the observed quark masses and CKM mixing angles, and remain consistent with experimental constraints on the extended scalar sector appearing in this Standard Model extension. In particular, the decay of the Standard Model-like Higgs boson into two light axions may be relevant and leads to a novel Higgs boson signature that may be searched for at the LHC in the near future.

scholarly journals One-loop nonbirefringent effects on the electromagnetic vertex in the Standard Model Extension

2014 ◽  
Vol 29 (22) ◽  
pp. 1450107 ◽  
Author(s):  
A. Moyotl ◽  
H. Novales-Sanchez ◽  
J. J. Toscano ◽  
E. S. Tututi
Keyword(s):  
Standard Model ◽  
Lorentz Invariance ◽  
Lorentz Violation ◽  
Tree Level ◽  
Isotropic Case ◽  
Photon Propagator ◽  
Standard Model Extension ◽  
Model Extension ◽  
The One ◽  
Electromagnetic Vertex

Lorentz violation emerged from a fundamental description of nature may impact, at low energies, the Maxwell sector, so that contributions from such new physics to the electromagnetic vertex would be induced. Particularly, nonbirefringent CPT-even effects from the electromagnetic sector modified by the Lorentz- and CPT-violating Standard Model Extension alter the structure of the free photon propagator. We calculate Lorentz-violating contributions to the electromagnetic vertex, at the one-loop level, by using a modified photon propagator carrying this sort of effects. We take the photon off shell, and find an expression that involves both isotropic and anisotropic effects of nonbirefringent violation of Lorentz invariance. Our analysis of the one-loop vertex function includes gauge invariance, transformation properties under C, P and T, and tree-level contributions from Lorentz-violating nonrenormalizable interactions. These elements add to previous studies of the one-loop contributions to the electromagnetic vertex in the context of Lorentz violation in the photon sector. Finally, we restrict our analysis to the isotropic case and derive a finite contribution from isotropic Lorentz violation to the anomalous magnetic moment of fermions that coincides with the result already reported in the literature.

scholarly journals Decays Z → γγ and Z → gg in the Standard Model Extension

2015 ◽  
Vol 30 (35) ◽  
pp. 1550216 ◽  
Author(s):  
J. Castro-Medina ◽  
H. Novales-Sanchez ◽  
J. J. Toscano ◽  
E. S. Tututi
Keyword(s):  
Standard Model ◽  
Background Field ◽  
Standard Model Extension ◽  
Gauge Invariant ◽  
Spatial Component ◽  
Loop Level ◽  
Model Extension ◽  
The Standard Model ◽  
Decay Widths ◽  
The One

The [Formula: see text] and [Formula: see text] decays are studied in the context of the renormalizable version of the Standard Model Extension. The [Formula: see text]-odd [Formula: see text] bilinear interaction, which involves the constant background field [Formula: see text] and which has been a subject of interest in literature, is considered. It is shown that the [Formula: see text] and [Formula: see text] decays, which are strictly zero in the standard model, can be generated radiatively at the one-loop level. It is found that these decays are gauge invariant and free of ultraviolet divergences, and that the corresponding decay widths only depend on the spatial component of the background field [Formula: see text].

scholarly journals D-oscillons in the standard model extension

2015 ◽  
Vol 91 (12) ◽  
Author(s):  
R. A. C. Correa ◽  
Roldão da Rocha ◽  
A. de Souza Dutra
Keyword(s):  
Standard Model ◽  
Standard Model Extension ◽  
Model Extension ◽  
The Standard Model

scholarly journals Lorentz Violation of the Photon Sector in Field Theory Models

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Lingli Zhou ◽  
Bo-Qiang Ma
Keyword(s):  
Field Theory ◽  
Standard Model ◽  
Degrees Of Freedom ◽  
Lorentz Violation ◽  
Detailed Structure ◽  
Standard Model Extension ◽  
Model Extension ◽  
The Standard Model ◽  
Minimal Standard

We compare the Lorentz violation terms of the pure photon sector between two field theory models, namely, the minimal standard model extension (SME) and the standard model supplement (SMS). From the requirement of the identity of the intersection for the two models, we find that the free photon sector of the SMS can be a subset of the photon sector of the minimal SME. We not only obtain some relations between the SME parameters but also get some constraints on the SMS parameters from the SME parameters. The CPT-odd coefficients(kAF)αof the SME are predicted to be zero. There are 15 degrees of freedom in the Lorentz violation matrixΔαβof free photons of the SMS related with the same number of degrees of freedom in the tensor coefficients(kF)αβμν, which are independent from each other in the minimal SME but are interrelated in the intersection of the SMS and the minimal SME. With the related degrees of freedom, we obtain the conservative constraints(2σ)on the elements of the photon Lorentz violation matrix. The detailed structure of the photon Lorentz violation matrix suggests some applications to the Lorentz violation experiments for photons.

scholarly journals Enhanced Derivation of the Electron Magnetic Moment Anomaly from the Electron Charge using Geometric Principles

2018 ◽  
Vol 10 (6) ◽  
pp. 24 ◽  
Author(s):  
Andrew Worsley ◽  
J.F. Peters
Keyword(s):  
Fine Structure ◽  
Standard Model ◽  
Magnetic Moment ◽  
Geometric Model ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Electron Charge ◽  
Mathematical Equation ◽  
The Standard Model ◽  
Electron Magnetic Moment

The electron magnetic moment anomaly is conventionally derived from the fine structure constant using a complex formula requiring over 13,000 evaluations. However, the charge of the electron is an important parameter of the Standard Model and could provide an enhanced basis for the derivation of the electron magnetic moment anomaly. This paper uses a geometric model to reformulate the equation for the electron’s charge, this is then used to determine a more accurate value for the electron magnetic moment anomaly from first geometric principles. This enhanced derivation uses a single evaluation, using a concise mathematical equation based on the natural log e^pi. This geometric model will lead to further work to theoretically improve the understanding of the electron.

scholarly journals Effects of Lorentz violation through the γe → Wνe process in the Standard Model extension

2014 ◽  
Vol 41 (5) ◽  
pp. 055003 ◽  
Author(s):  
J I Aranda ◽  
F Ramírez-Zavaleta ◽  
D A Rosete ◽  
F J Tlachino ◽  
J J Toscano ◽  
...  
Keyword(s):  
Standard Model ◽  
Lorentz Violation ◽  
Standard Model Extension ◽  
Model Extension ◽  
The Standard Model
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