Currently the phenomena of neutrino and neutral kaon oscillations, which take place at finite space-time intervals, are usually described in the framework of approaches that are inconsistent or not convenient for describing such processes. We develop a new QFT approach, adjusting the standard S-matrix formalism for the case. One applies the usual Feynman rules in the coordinate representation...
Development of a distributed system of the neutron monitors is required to estimate the neutron spectra and monitor the neutron fields in the CMS experimental cavern. The proposed neutron monitor is based on the 6Li-enriched scintillator coupled to SiPM. During LHC Run 2, several monitor samples were successfully commissioned at the CERN laboratory and tested in CMS environment with the set of...
It is conveniently to use a model-independent approach of effective field theory for indirect search of new physics. This approach consists of parametrization of the lagrangian with operators of higher dimensons with some coefficients. If we compare experimental data with Monte Carlo results, it becomes possible to impose an upper limit of the value of coefficients. However, the real value of...
The uncertainty in tau neutrino production in high energy proton interactions has been the largest uncertainty in current and future tau neutrino measurements, preventing a precise test of lepton universality in neutrino scattering. DsTau (NA65) at the CERN-SPS is a recently approved experiment, which aims to study the problematic tau neutrino production. The main source of tau neutrino...
The main purpose of this work is to obtain the Electromagnetic Stress-Energy Tensor in a medium for a nonlocal theory. In order to get it, we generalise Minkowski electrodynamics to dispersive media. As a consequence of this generalisation, the Lagrangian density becomes non-local due to the non-local dependencies of the magnetic permeability and electric permittivity. This leads a convolution...
Luminosity is one of the main characteristics of an accelerator. It determines the number of colliding particle (e.g. protons) interactions in a bunch crossing. The task of luminosity measurements in two-beam experiments is challenging. It becomes harder with the LHC upgrade – High-Luminosity LHC – with even higher energies, luminosity and a complex time structure of the beam. The proposed...
The recently suggested generalized unimodular gravity theory, which was originally put forward as a model of dark energy, can serve as a model of cosmological inflation driven by the effective perfect fluid—the dark purely gravitational sector of the theory. Its excitations are scalar gravitons that can generate, in the domain free from ghost and gradient instabilities, the red tilted...
When quantizing theory in curved space-time, one can define vacuum state with respect to different timelike Killing vectors. In case of Schwarzschild space-time one usually considers Boulware, Unruh and Hartle-Hawking vacua, where the latter two use Kruskal null coordinates to define positive-frequency modes. Loop corrections to the occupation numbers and anomalous quantum averages are...
The DANSS experiment aims to search for sterile neutrinos. It is a compact neutrino spectrometer located at the Kalinin Nuclear Power Plant close to the core of the industrial power reactor. The detector records about 3000-4000 events per day after subtracting the background depending on the position. The significant contribution to background events is made by neutrons from the interaction of...
We show the explicit mode expansion of tree-level propagators in Static (or Compact) Patch of de Sitter space. We construct propagator for thermal state corresponding to arbitrary temperature $T$. We show that the propagator that respects the de Sitter isometry corresponds to the thermal state with $T = (2 \pi)^{-1}$ in the units of de Sitter curvature. Which confirms the old and well known...
We consider (0+1) and (1+1) dimensional Yukawa theory in various scalar field backgrounds, which are solving classical equations of motion. The (0+1)–dimensional theory we solve exactly. In (1+1)–dimensions we consider background fields of the form $\phi_{cl} = Et$ and $\phi_{cl} = Ex$, which are inspired by the constant electric field. Here E is a constant. We study the backreaction problem...
During inflation the universe rapidly expands and the observed classical distribution of inhomogeneities originates from the substantially non-classical state. The problem of transition from quantum to classical behavior is also important outside the cosmological context in connection with the study of mesoscopic systems. And this problem can be viewed in the context of the theory of...
Nuclear radiative recoil corrections of order \alpha(Z*\alpha)^5 to the hyperfine structure of S-states in light muonic atoms are calculated in the framework of quasipotential method in quantum electrodynamics. Separate expressions for the contributions of the muon self-energy, muon vertex operator and the amplitude with spanning photon are obtained. For the radiative photon, we use the...
The lead tungstate crystal (PbWO4, PWO) is one of the widely used scintillation materials for electromagnetic calorimeters in high energy physics experiments. The degradation of the optical transmittance in the range of the luminescence spectrum under ionizing radiation leads to losses of the light output resulting in the deterioration of the energy resolution and limiting the life time of the...
An object of the crucial importance in quantum field theory is the effective action. By definition, it is a generating functional for one-particle irreducible Green's functions, which contains complete information about the quantum properties of this model. To find an effective action, it is convenient to use the technique of harmonic superspace.
Superspace[1] is a generalization of Minkowski...
The new large-scale coordinate-tracking detector TREK is being developed at National Research University MEPhI. The aim of the project is the solution of so-called “muon puzzle”: the unpredicted by any theory excess of high multiplicity muon bundles generated by ultra-high energy primary cosmic rays. The joint operation with Cherenkov water detector NEVOD will allow investigation specific...
The technology of highly granular calorimeters is one of the innovations that will be implemented in the planned accelerator experiments, for example in the future linear collider. The work is devoted to the study of hadronic showers in the highly granular hadron calorimeter of the ILD detector and the application of machine learning to the improvement of the energy resolution. The artificial...
