Abstract We compute next-to-leading order virtual two-loop corrections to the process gg → Z Z in the low- and high-energy limits, considering the contributions with virtual top quarks. Analytic results for all 20 form factors are presented including expansion terms up to \( 1/{m}_t^{12} \) and \( {m}_t^{32} \). We use a Padé approximation procedure to extend the radius of convergence of the high-energy

Abstract The problem of constructing gauge-invariant actions for conformal higher-spin fields in curved backgrounds is known to be notoriously difficult. In this paper we present gauge-invariant models for conformal maximal depth fields with spin s = 5/2 and s = 3 in four-dimensional Bach-flat backgrounds. We find that certain lower-spin fields must be introduced to ensure gauge invariance when s >

Abstract Exclusive rare decays mediated by b → sℓℓ transitions receive contributions from four-quark operators that cannot be naively expressed in terms of local form factors. Instead, one needs to calculate a matrix element of a bilocal operator. In certain kinematic regions, this bilocal operator obeys some type of Operator Product Expansion, with coefficients that can be calculated in perturbation

Abstract We discuss the dRGT massive gravity interacting with spin-0, spin-1/2, or spin-1 matter. The effective theory of a massive spin-2 particle coupled to matter particles is constructed directly at the amplitude level. In this setting we calculate the gravitational Compton scattering amplitudes and study their UV properties. While the Compton am- plitudes generically grow with energy as O(E6)

Abstract We study the relation between entropy and Action Complexity (AC) for various examples of cosmological singularities in General Relativity. The complexity is defined with respect to the causal domain of dependence of the singular set, and the entropy is evaluated on the boundary of the same causal domain. We find that, contrary to the situation for black hole singularities, the complexity growth

Abstract The searching for the electric dipole moments (EDMs) of neutron (dn), b quark (db) and c quark (dc) gives strict upper bounds on these quantities. And recently, new up- per bounds on db, dc are obtained by the strict limit on dn. The models of new physics (NP) with additional CP-violating (CPV) sources are constrained strictly by these EDMs. In this work, we focus on the CPV effects on these

Abstract We perform a global fit within the pseudo-Nambu-Goldstone Dark Matter (DM) model emerging from an additional complex scalar singlet with a softly broken global U (1) symmetry. Leading to a momentum-suppressed DM-nucleon cross section at tree level, the model provides a natural explanation for the null results from direct detection experiments. Our global fit combines constraints from perturbative

Abstract In this note we analyze the relative scales for the GUT and twin sectors in the F-theory model discussed in ref. [1]. There are a number of volume moduli in the model. The volume of the GUT surface in the visible sector (1) (with the Wilson line GUT breaking) defines the GUT scale MG∼ 2 × 1016GeV as the unification scale with precise gauge coupling unification of SU(3) × SU(2) × U(1)Y . We

Abstract To solve the μ problem and generate three tiny neutrino masses in the MSSM, the μ from ν Supersymmetric Standard Model (μνSSM) introduces three singlet right- handed neutrino superfields, which lead to the mixing of the Higgs doublets with the sneutrinos. The mixing affects the lightest Higgs boson mass and the Higgs couplings. The present observed 95% CL upper limit on signal strength of

Abstract We analyze the 2+1 dimensional gauge theory with two fermions in the real ad-joint representation with non-zero Chern-Simons level. We propose a new fermion-fermion dualities between strongly-coupled theories and determine the quantum phase using the structure of a ‘Duality Chain’. We argue that when Chern-Simons level is sufficiently small, the theory in general develops a strongly coupled

Abstract We examine the vacuum structure of 4D effective theories of moduli fields in spacetime compactifications with quantized background fluxes. Imposing the no-scale structure for the volume deformations, we numerically investigate the distributions of flux vacua of the effective potential in complex structure moduli and axio-dilaton directions for two explicit examples in Type IIB string theory

Abstract Fixed-target experiments using primary electron beams can be powerful discovery tools for light dark matter in the sub-GeV mass range. The Light Dark Matter eXperiment (LDMX) is designed to measure missing momentum in high-rate electron fixed-target reactions with beam energies of 4 GeV to 16 GeV. A prerequisite for achieving several important sensitivity milestones is the capability to efficiently

Abstract SHiP is a proposed high-intensity beam dump experiment set to operate at the CERN SPS. It is expected to have an unprecedented sensitivity to a variety of models containing feebly interacting particles, such as Heavy Neutral Leptons (HNLs). Two HNLs or more could successfully explain the observed neutrino masses through the seesaw mechanism. If, in addition, they are quasi-degenerate, they

Abstract New Physics can manifest itself in kinematic distributions of particle decays. The parameter space defining the shape of such distributions can be large which is chalenging for both theoretical and experimental studies. Using clustering algorithms, the parameter space can however be dissected into subsets (clusters) which correspond to similar kinematic distributions. Clusters can then be

This paper studies a two-phase loop thermosiphon as a potential cooling solution for thermal management of insulated gate bipolar transistors (IGBTs). Water-based two-phase thermosiphon is initially analyzed. The flow instabilities of the loop and impact of different parameters such as heat flux, valve control near the inlet, and static head in the reservoir on thermosiphon performance are investigated

Vanadium dioxide (VO2) is a well-known material for its semiconductor to metallic (SMT) phase change at 68 °C. Temperature controlled changes in optical, structural and electrical properties may lead to many applications in photonics, plasmonics and electronics. The present study explores vanadium oxide thin films growth by Pulsed-Laser Deposition and Rapid Thermal Annealing. 25 nm thick films are

Abstract In this paper, a broadband single polarization photonic crystal fiber (PCF) filter around 1.55 μm is presented on account of surface plasmon resonance. The finite element method is used to investigate the performance of the filter, and the structure parameters’ influences on the performances of the filter are studied. Due to asymmetry which is caused by the pentagonal arranged cladding air

This paper involves a numerical study of several water – ionic liquids mixtures and nanoparticle enhanced ionic liquids starting from a less studied ionic liquid: 1-Ethyl-3-methylimidazolium Methanesulfonate, [C2mim][CH3SO3]. The research start point was several previous published experimental results in regard to the water – ionic liquid mixtures and alumina based nanoparticle enhanced ionic liquids

Recent electronic industry developments require a variety of compact and high-performance heat sinks for the heat dissipation of electronic devices. In this paper, on the basis of a new type of heat pipe called the metal foam multichannel heat pipe (metal foam MCHP) proposed by our team, an experimental apparatus on its heat transfer characteristics was built. The heat transfer characteristics of the

We present a variational assimilation technique (4D-Var) to reconstruct time resolved incompressible turbulent flows from measurements on two orthogonal 2D planes. The proposed technique incorporates an error term associated to the flow dynamics. It is therefore a compromise between a strong constraint assimilation procedure (for which the dynamical model is assumed to be perfectly known) and a weak

In this paper, we present a new implicit Monte-Carlo scheme for photonics. The new solver combines the benefits of both the IMC solver of Fleck & Cummings and the SMC solver of Ahrens & Larsen. It is implicit hence allows taking affordable time steps (as IMC) and has no teleportation error (as SMC). The paper also provides some original analysis of existing schemes (IMC, tilted IMC, SMC), especially

The eigensystem of the Pulliam-Chaussee diagonalized form of the approximate-factorization algorithm for the three-dimensional Euler and Navier-Stokes equations is revisited to remove an apparent dimensional inconsistency. The original set of eigenvectors in curvilinear coordinates were derived systematically and has been widely used and referenced. Although mathematically correct, the original eigenvectors

The particle-in-cell (PIC) method is widely used to model the self-consistent interaction between discrete particles and electromagnetic fields. It has been successfully applied to problems across plasma physics including plasma based acceleration, inertial confinement fusion, magnetically confined fusion, space physics, astrophysics, high energy density plasmas. In many cases the physics involves

In this article, we propose a novel method for sampling potential functions based on noisy observation data of a finite number of observables in quantum canonical ensembles, which leads to the accurate sampling of a wide class of test observables. The method is based on the Bayesian inversion framework, which provides a platform for analyzing the posterior distribution and naturally leads to an efficient

A hybrid method is developed to solve the interaction problem of wave with a three dimensional floating structure in a polynya. The linearized velocity potential theory is used for fluid flow, and the thin elastic plate model is adopted for the infinitely extended ice sheet. Because of sudden change of the upper boundary of the computational domain, namely from the ice sheet to the free surface, the

The paper investigates the in-plane vibration property of static and rotating tires with the proposed tire model. The tire model is based on the linear ring model, and a mathematical approach is proposed to handle the tire contact problem. With this improvement, the tire model allows for directly calculating the eigenmodes of a loaded tire by solving its eigenvalue problem. A group of simulations is

Experimental measurements were carried out to assess the aerodynamic and aeroacoustic performance of an MDA 30P30 N airfoil fitted with two different types of slat cove fillers. The aerodynamic results are presented for lift and drag measurements and mean surface pressure measurements, while the aeroacoustic results are presented for the near-field surface pressure fluctuations and far-field noise

Multiple moving sound sources’ aliasing problem occurs in many fields. The number and relative position of these sources provide critical information for further signal processing. However, estimating the number and relative position under aliasing of multiple moving sound source is challenging. In this study, the Fibonacci sequence was applied to design a novel two-dimensional Fibonacci array, which

The Acoustic Black Hole (ABH) is a technique for passive vibration control that was recently developed within the Structural Dynamics and Vibroacoustics communities. From a general perspective, the ABH effect is achieved by embedding a local inhomogeneity in a thin-walled structure, typically a beam or a plate. This inhomogeneity is characterized by a variation of the geometric properties (although

The magnetized anisotropic ion apparatus (MARIA) was constructed to study the density buildup and particle balance in helicon plasmas. This device will help address key questions surrounding the dynamics of the neutral argon population and the role it plays in defining the ultimate density achieved. Insights gained from this research are particularly important for meeting the demanding high density

This work presents swarm parameters of electrons (the bulk drift velocity, the bulk longitudinal component of the diffusion tensor, and the effective ionization frequency) in C 2 H n , with n = 2, 4, and 6, measured in a scanning drift tube apparatus under time-of-flight conditions over a wide range of the reduced electric field, 1Td ≤ E/N ≤ 1790 Td (1 Td = 10 −21 V m 2 ). The effective steady-state

(2020). Preface for Special Issue “Bioaerosol Research: Methods, Challenges, and Perspectives”. Aerosol Science and Technology: Vol. 54, Bioaerosol Research: Methods, Challenges, and Perspectives, pp. 463-464.

Abstract Detection of bioaerosols, or primary biological aerosol particles (PBAPs), has become increasingly important for a wide variety of research communities and scientific questions. In particular, real-time (RT) techniques for autonomous, online detection and characterization of PBAP properties in both outdoor and indoor environments are becoming more commonplace and have opened avenues of research

Bioaerosol sampling is an essential and integral part of any bioaerosol investigation. Since bioaerosols are very diverse in terms of their sizes, species, biological properties, and requirements for their detection and quantification, bioaerosol sampling is an active, yet challenging research area. This article was inspired by the discussions during the 2018 International Aerosol Conference (IAC)

Abstract Outdoor field measurements of bioaerosols are performed within a wide range of basic and applied scientific disciplines, each with its own goals, assumptions, and terminology. This article contains brief reviews of outdoor field bioaerosol research from these diverse interests, with emphasis on perspectives from the atmospheric sciences. The focus is on a high-level discussion of pressing

Experimental aerosol generation methods aim to represent natural processes; however, the complexity is not always captured and unforeseen variability may be introduced into the data. The current practices for natural and experimental aerosol generation techniques are reviewed here. Recommendations for best practice are presented, and include characterization of starting material and spray fluid, rational

Because bioaerosols are related to adverse health effects in exposed humans and indoor environments represent a unique framework of exposure, concerns about indoor bioaerosols have risen over recent years. One of the major issues in indoor bioaerosol research is the lack of standardization in the methodology, from air sampling strategies and sample treatment to the analytical methods applied. The main

Abstract Biological aerosol particles have been studied in the laboratory for many decades to understand their roles in human health and disease and in environmental processes. These studies have used a variety of instrumentation under varying conditions. This review covers the most common types of bioaerosol chambers (e.g., static, flow-through and rotating drum), the study of biological particles

One issue that has persisted since the beginning of what might be referred to as a modern era of biological aerosol research (since the 1990’s), is absence of reference biological aerosols that would permit quantitative comparison among different experimental studies. We believe sufficient technical progress has been made bridging the diverse fields of biology, chemistry, physics and engineering to

In recent years, much attention has been drawn to the exposure to bioaerosols in both occupational and indoor environments due to adverse effects on human health. Exposure to these agents may cause infectious diseases, allergic diseases, acute toxic effects, respiratory diseases, neurological effects, and cancer. Bioaerosols play a significant role in air quality studies, as well as in industrial and

Abstract We investigate the production of axion quanta during the early universe evolution of an axion-like field rolling down a wiggly potential. We compute the growth of quantum fluctuations and their back-reaction on the homogeneous zero-mode. We evaluate the transfer of kinetic energy from the zero mode to the quantum fluctuations and the conditions to decelerate the axion zero-mode as a function

Abstract We construct a general form for an F-theory Weierstrass model over a general base giving a 6D or 4D supergravity theory with gauge group (SU(3) × SU(2) × U(1))/ℤ6 and generic associated matter, which includes the matter content of the standard model. The Weierstrass model is identified by unHiggsing a model with U(1) gauge symmetry and charges q ≤ 4 previously found by the first author. This

Abstract A new U (1) gauge symmetry is the simplest extension of the Standard Model and has various theoretical and phenomenological motivations. In this paper, we study the cosmological constraint on the MeV scale dark photon. After the neutrino decoupling era at T = O(1) MeV, the decay and annihilation of the dark photon heats up the electron and photon plasma and accordingly decreases the effective

Abstract In this note we analyze the BPS black hole equations in extended supergravities and we find two interesting relations involving first and second derivatives of combinations of the central charges. One relation is a new identity that solely relies on the geometric properties of the scalar manifolds of extended supergravity theories. The other relation is a generalization of a scalar weak gravity

Abstract We constrain the Higgs-portal model employing the vector-boson fusion channel at the LHC. In particular, we include the phenomenologically interesting parameter region near the Higgs resonance, where the Higgs-boson mass is close to the threshold for dark-matter production and a running-width prescription has to be employed for the Higgs- boson propagator. Limits for the Higgs-portal coupling

Abstract We explore systematically perturbations of self-similar solutions to the Einstein-axion-dilaton system, whose dynamics are invariant under spacetime dilations combined with internal 𝔰𝔩(2, ℝ) transformations. The self-similar solutions capture the enticing behavior “critical” systems on the verge of gravitational collapse, in arbitrary spacetime dimensions. Our methods rest on a combination

Abstract This paper deals with the development and analysis of D-Shaped photonic crystal fiber (PCF) biosensors using surface plasmon resonance (SPR). A thin metal layer is deposited on the outer flat surface of the PCF that behaves as the plasmonic material. Analyte is filled in the outermost peripheral region of metal layer. Finite element method (FEM) with perfectly matched layer (PML) is applied

Abstract In this paper, a reconfigurable beam-scanning planar antenna is proposed in terahertz frequencies. The presented structure consists of a semi bow tie antenna surrounded by circularly arranged parasitic pieces of graphene. The performance of the proposed antenna is investigated considering three different states where a PEC ground plane and a graphene ground layer with chemical potentials 0

Fouling is one of the customarily happened, fundamental and expensive problems in heat transfer systems. It causes the reduction in heat transfer performance of the heat exchangers, energy loss and also, damage to the apparatus. Effect of fluid flow rate on the salt deposition was complicated in the previous researches. In this paper, a comprehensive rigorous investigation was performed to make clear

Proper thermal management through an effective cooling mechanism is essential for improving the reliability of operation of various electronic devices. A number of cooling methods are available among which passive cooling by natural convection has been deemed appropriate since it has distinctive advantages over active cooling or forced convection like high reliability, low maintenance cost, energy

Due to the high energy density of laser diode (LD), the fluorescent convertor always suffers from serious overheating problems, such as thermal quenching, significant efficiency drop or even material carbonization failure. In this work, we improved the current optical-thermal model by coupling the optical behavior of red (nitride)/yellow (YAG) phosphor and thermal conductivity of different hybrid particles

In this article, a computational study of the thermal management of thermoelectric generator (TEG) with phase change materials (PCM) is made. The test model has been developed and studied using COMSOL Multiphysics. The thermal management of thermoelectric generator is studied using the heat sink encapsulating with the phase change materials through variations in the heat input and the quantity of PCM