Demonstration of Dipole-Induced Transparency Using Mirrored Split-Ring Resonator Metasurface For Microwave Applications

In this paper, dipole-induced transparency in the microwave regime is proposed and verified using experimental and simulation studies. A single layer mirrored Split-Ring Resonator (SRR) metasurface array working under the H⊥excitation scenario is used to achieveout-of-phase electric dipole moments on the metasurface for a normal incident plane wave. The emergence of the transparency window is accompanied by the destructive interference between out-of-phase oscillating electric dipole moments on the metasurfaceand is verified in computations by studying the radar Cross Section in full-wave electromagnetic simulations.We used the multipole scattering theory to validate the results computationally. The coupling effects are studied numerically, and the emergence of the transparency window is studied experimentally using transmission measurements inside an anechoic chamber using a vector network analyzer.

Universal scalar leptoquark action for matching

In this study we present a universal effective action for one-loop matching of all scalar leptoquarks. We use both the Universal One-Loop Effective Action (UOLEA) and covariant diagrams to evaluate the Wilson coefficients directly in the Green basis for up to dimension-6 operators. On the technical side, we use the newly developed method of evaluating supertraces, to further validate the results stemming from the use of covariant diagrams. As an application, we perform a fully functional matching onto Standard Model Effective Field Theory (SMEFT) of a model with two scalar leptoquark fields: a weak isospin singlet and a doublet. We demonstrate its use by calculating several observables, such as lepton magnetic and electric dipole moments, neutrino masses, proton decay rate, while we comment upon fine tuning issues in this model. Apart from its phenomenological interest, this model generates the majority of dimension-6 operators and provides an EFT benchmark towards future matching automation.

A pseudo anapole based electromagnetic cloaking scheme using Split Ring Resonators

This paper proposes the first experimental demonstration of a pseudo-anapole-based cylindrical electromagnetic cloaking scheme. The pseudo-anapole state is excited by arranging split-ring resonators around a cylindrical metallic target. We used the multipole scattering theory to identify the actual reason behind the cloaking operation. Pseudo anapole condition is characterized by the scattering minima from toroidal and electric dipole moments, and hence the metallic target is undetectable from backscattering measurements. The results are verified using full-wave simulation software and subsequently validated with backscattering measurements inside an anechoic chamber.

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.

Supersymmetric alignment models for (g − 2)μ

Hierarchical masses of quarks and leptons are addressed by imposing horizontal symmetries. In supersymmetric Standard Models, the same symmetries play a role in suppressing flavor violating processes induced by supersymmetric particles. Combining the idea of spontaneous CP violation to control contributions to electric dipole moments (EDMs), the mass scale of supersymmetric particles can be lowered. We present supersymmetric models with U(1) horizontal symmetries and discuss CP and flavor constraints. Models with two U(1) symmetries are found to give a viable solution to the muon g − 2 anomaly. Interestingly, the parameter space to explain the anomaly will be probed by future electron EDM experiments.