Vanishing or non-vanishing rainbow? Reduction formulas of electric dipole moment

In this paper, we derive a simplified formula of electric dipole moments (EDMs) of a fermion. In the Standard Model, it is well-known that non-trivial cancellations between some rainbow-type diagrams induced by W boson exchanges occur in the calculation of the neutron EDM at the two-loop level due to the gauge symmetry. The fermion self-energy and the vertex correction are related through the Ward-Takahashi identity, and this relation causes the exact cancellation of the EDM. We derive EDM formulas for a more general setup by introducing the form factors for the fermion self-energy and the vertex correction so that the derived formulas can be applicable to a larger class of models. We conclude that the non-zero EDM contributions are induced from rainbow-type diagrams with the chirality flipping effects for internal fermions. We also discuss the other possible generalization of the EDM calculation which is applicable to the other classes of models.

Properties Evaluation of Fe95-xSi5Nix Under the Earth's Inner-Core Conditions: Insight from the Ab-Initio Investigation

In this article we investigate under the same Earth's core conditions, the structural, electronic, and transport properties of Fe-Si-Ni ternary alloys based on Fe and 5% of Si with various concentrations 0%, 15%, 25%, and 40% of element Ni, by means of First-principles calculations. Based on Functional Density Theory (DFT). The Local Density Approximation (LDA) also has been adopted for the potential exchange correlation. We perform the calculation of electronic property at 360 GPa using the software Akai-KKR (machikaneyama), which used the Korringa-Kohn-Rostoker method along with coherent potential approximation (KKR-CPA). Afterward, we calculate the electrical resistivity of impurities formed on the Kubo-Greenwood formula with the vertex correction using SPR-KKR code, which is based on the relativistic polarized spin method. Then, we model the thermal conductivity by electrical resistivity for both varying in the range of 320–360 GPa and 4500-6000k of pressure and temperature, respectively; according to the conditions of the Earth’s inner core ICB using Wiedemann-Franz law. Hence, our results suggest that 85–115 µΩ·cm at 0 K and 320–360 GPa, then 225–285 µΩ·cm at 4500–6000 K and 360 GPa for electrical resistivity, and then 45–55 W·m− 1·K− 1 at 4500–6000 K and 360 GPa of thermal conductivity of Earth’s inner core. Lastly, the thermal and compositional convection is one of the major factors of global magnetic field that is generated by geodynamo driven.

Erratum to: Light quark mediated Higgs boson threshold production in the next-to-leading logarithmic approximation

In the paper a NLL contribution of the gluon vertex correction figure 4(c) has been omitted.

Stuckelberg SUSY QED and infrared problem

We review gauge invariant [Formula: see text] supersymmetric massive U(1) gauge theory coupled to matter and Stuckelberg superfields. We focus on the leading order self-energy and vertex correction to the matter field in the massless limit of both the U(1) vector superfield and the Stuckelberg superfield. We explicitly verify that the theory is infrared divergence free in the massless limit. Hence the Stuckelberg mechanism appears to be the efficient route to handle infrared divergences seen in supersymmetric quantum electrodynamics. Since these additional particles have very small masses they can serve as dark matter candidates through “Ultralight particles” mechanism.

Light-front QED, Stueckelberg field and infrared divergence

Stueckelberg mechanism introduces a scalar field, known as Stueckelberg field, so that gauge symmetry is preserved in the massive Abelian gauge theory. In this work, we show that the role of the Stueckelberg field is similar to the Kulish and Faddeev coherent state approach to handle infrared (IR) divergences. We expect that the light-front quantum electrodynamics (LFQED) with Stueckelberg field must be IR finite in the massless limit of the gauge boson. We have explicitly shown the cancellation of IR divergences in the relevant diagrams contributing to self-energy and vertex correction at leading order.