Next-to-leading-order QCD corrections and parton-shower effects for weakino+squark production at the LHC

We present a calculation of the next-to-leading order QCD corrections to weakino+squark production processes at hadron colliders and their implementation in the framework of the POWHEG-BOX, a tool for the matching of fixed-order perturbative calculations with parton-shower programs. Particular care is taken in the subtraction of on-shell resonances in the real-emission corrections that have to be assigned to production processes of a different type. In order to illustrate the capabilities of our code, representative results are shown for selected SUSY parameter points in the pMSSM11. The perturbative stability of the calculation is assessed for the pp →$$ {\tilde{\upchi}}_1^0{\tilde{d}}_L $$ χ ˜ 1 0 d ˜ L process. For the squark+chargino production process pp →$$ {\upchi}_1^{-}{\tilde{u}}_L $$ χ 1 − u ˜ L distributions of the chargino’s decay products are provided with the help of the decay feature of PYTHIA 8.

A satellite-data-driven framework to rapidly quantify air-basin-scale NO_<i>x</i> emissions and its application to the Po Valley during the COVID-19 pandemic

The evolving nature of the COVID-19 pandemic necessitates timely estimates of the resultant perturbations to anthropogenic emissions. Here we present a novel framework based on the relationships between observed column abundance and wind speed to rapidly estimate the air-basin-scale NOx emission rate and apply it at the Po Valley in Italy using OMI and TROPOMI NO2 tropospheric column observations. The NOx chemical lifetime is retrieved together with the emission rate and found to be 15–20 h in winter and 5–6 h in summer. A statistical model is trained using the estimated emission rates before the pandemic to predict the trajectory without COVID-19. Compared with this business-as-usual trajectory, the real emission rates show three distinctive drops in March 2020 (−42 %), November 2020 (−38 %), and March 2021 (−39 %) that correspond to tightened COVID-19 control measures. The temporal variation of pandemic-induced NOx emission changes qualitatively agrees with Google and Apple mobility indicators. The overall net NOx emission reduction in 2020 due to the COVID-19 pandemic is estimated to be 22 %.

The eikonal approach to gravitational scattering and radiation at $$ \mathcal{O} $$(G3)

Using $$ \mathcal{N} $$ N = 8 supergravity as a theoretical laboratory, we extract the 3PM gravitational eikonal for two colliding massive scalars from the classical limit of the corresponding elastic two-loop amplitude. We employ the eikonal phase to obtain the physical deflection angle and to show how its non-relativistic (NR) and ultra-relativistic (UR) regimes are smoothly connected. Such a smooth interpolation rests on keeping contributions to the loop integrals originating from the full soft region, rather than restricting it to its potential sub-region. This task is efficiently carried out by using the method of differential equations with complete near-static boundary conditions. In contrast to the potential-region result, the physical deflection angle includes radiation-reaction contributions that are essential for recovering the finite and universal UR limit implied by general analyticity and crossing arguments. We finally discuss the real emission of massless states, which accounts for the imaginary part of the 3PM eikonal and for the dissipation of energy-momentum. Adopting a direct approach based on unitarity and on the classical limit of the inelastic tree-level amplitude, we are able to treat $$ \mathcal{N} $$ N = 8 and General Relativity on the same footing, and to complete the conservative 3PM eikonal in Einstein’s gravity by the addition of the radiation-reaction contribution. We also show how this approach can be used to compute waveforms, as well as the differential and integrated spectra, for the different radiated massless fields.

One-loop radiative corrections to e+e− → Zh0/H0A0 in the Inert Higgs Doublet Model

We compute the full one-loop radiative corrections (including both weak and QED corrections) for two processes e+e− → Zh0, H0A0 in the Inert Higgs Doublet model (IHDM). Up to O(αw) and O(αem) order, we use FeynArts/FormCalc to compute the one-loop virtual corrections and Feynman Diagram Calculation (FDC) to evaluate the real emission, respectively. Being equipped with these computing tools, we investigate radiative corrections of new physics for five scenarios with three typical collision energies of future electron-positron colliders: 250 GeV, 500 GeV, and 1000 GeV. By scanning the parameter space of IHDM, we identify the allowed regions which are consistent with constraints and bounds, from both theoretical and experimental sides. We find that the radiative corrections of the IHDM to e+e− → Zh0 can be sizeable and are within the detection potentials of future Higgs factories. We also find that the new physics of IHDM could also be directly detected by observing the process e+e− → H0A0 which could have large enough production rate. We propose six benchmark points and examine their salient features which can serve as physics targets for future electron-positron colliders, such as CEPC/CLIC/FCC-ee/ILC as well as for LHC.

Mathematical and Numerical Modeling of On-Threshold Modes of 2-D Microcavity Lasers with Piercing Holes

This study considers the mathematical analysis framework aimed at the adequate description of the modes of lasers on the threshold of non-attenuated in time light emission. The lasers are viewed as open dielectric resonators equipped with active regions, filled in with gain material. We introduce a generalized complex-frequency eigenvalue problem for such cavities and prove important properties of the spectrum of its eigensolutions. This involves reduction of the problem to the set of the Muller boundary integral equations and their discretization with the Nystrom technique. Embedded into this general framework is the application-oriented lasing eigenvalue problem, where the real emission frequencies and the threshold gain values together form two-component eigenvalues. As an example of on-threshold mode study, we present numerical results related to the two-dimensional laser shaped as an active equilateral triangle with a round piercing hole. It is demonstrated that the threshold of lasing and the directivity of light emission, for each mode, can be efficiently manipulated with the aid of the size and, especially, the placement of the piercing hole, while the frequency of emission remains largely intact.

Investigation of the possibility to compensate for the blooming effect in CCD optical spectral sensors

The multipixel semiconductor light sensors are becoming more and more popular in the spectroscopy practice. But insufficient for the spectroscopy dynamic range and nonlinearity of such sensors are well known. The described experiment shows nonlinearity of the sensor starting from certain light level. The role of blooming effect is shown on different complex spectral reliefs. The aim of this work was to carry out comparative studies of the dynamic range of sensors depending on the presence of anti-blooming, as well as to develop ways to expand the dynamic range during spectrophotometric measurements. Based on common sense and the analysis of previous experiments it is reasonable to assume that registration of the same spectral region with bidirectional transportation of charges in CCD devices could give extra advantages for the following linearization. In order to investigate the problem, a camera was created that allows recording the same plots of the spectrum with pairs of detector lines with the opposite direction of charge transport in charge-coupled devices (CCD). The paper presents a description of the technical solutions used in the development of the camera and the results of measurements of real emission spectra. The methods for processing data recorded during such spectrum registering are proposed. The possibility of a significant expansion of the dynamic range in the field of large signals is shown. The results of the experiment prove the possibility of using the proposed method for linearization of over-illuminated spectral line images. The comparison of the non-linearity of several types of sensors with different anti-blooming capabilities was performed. The described technology may be used for developing multisensor CCD spectral cameras.