Vol 117, No 3-4 (2) (2023)

The  process with the subsequent decay of the Higgs boson is studied, where both Z bosons are reconstructed in the final states with two jets. The analysis is performed using Monte Carlo data samples obtained with detailed ILD detector simulation assuming an integrated luminosity of 2 ab–1, beam polarizations of 
, and center-of-mass energy of  GeV for the electron–positron International Linear Collider being currently designed. The analysis is repeated for the case of two 0.9 ab–1 data samples with polarizations . Contributions of the potential background processes are studied using all available ILD MC event samples. The largest background comes from the  process supplemented by an energetic photon produced by initial state radiation. To suppress this background, we require that at least one of the Z bosons decays to b-jets. To reduce the jet reconstruction uncertainties the  variable is used, where  GeV. The  distributions are obtained for the studied signal and backgrounds to estimate the expected accuracy of the  measurement. The accuracy is 22% for the option of the single polarization sample described above and deteriorate to 24% in case of the sample with two polarizations. The proposed method can be applied at any future  collider.

A method for generating short pulses with a high repetition rate is proposed. It is based on periodic modulation of the radiation phase of a CW laser and subsequent filtering through a narrow-band frequency filter. At the output of the filter, a sequence of short pulses is generated with a period equal to half the modulation period. In the case of a resonant filter using atoms, ions or molecules with a narrow absorption line, the appearance of pulses can be explained by constructive interference of the incident radiation with radiation coherently scattered by resonant particles. An alternative explanation of the pulse generation in the general case, when frequency filters operating on other principles are used, is based on the interference of the spectral components remaining after filtering. The method can be applied for time division multiplexing to transmit digital information through a single channel at high speed. The advantage of the proposed method is the use of phase modulation (not strictly periodic), integrated with frequency filtering to generate pulses and encode information simultaneously in one circuit, while in other known methods, information is introduced into a sequence of regularly generated pulses using additional amplitude modulation.

A new type of ghost fiber optic endoscopy has been proposed to obtain ghost images of three-dimensional optically transparent objects. The method is based on spatial and temporal correlation of light beams formed in a bundle of single-mode fibers exposed in the transverse direction to femtosecond laser pulses. Resolution in the depth of an object is ensured by an original algorithm to reconstruct images, which involves both the properties of femtosecond radiation and the features of light propagation in an inhomogeneous scattering medium. The effectiveness of the proposed method has been confirmed by a numerical simulation by an example of an octahedron with a layered structure.

An exact solution to the Maxwell–Vlasov equations has been found for a large class of multicomponent current sheets in collisionless plasma, which describe the spatial structure of the current in the magnetopause and consistent inhomogeneous anisotropic momentum distributions of particles with different effective temperatures. Devised sheets allow a nonmonotonic variation of the magnetic field and can have asymmetric, multihump, and sign-alternating profiles of the current density. Profiles of the current of different particle populations can have different scales, contain countercurrents, and be spatially shifted with respect to each other. The model under consideration is applicable to qualitatively describe a magnetopause separating a magnetosphere of a planet from a solar wind or separating regions of the solar wind with different parameters of the plasma and magnetic field.

Vanadium-containing heterostructures consisting of an ultrathin magnetic film on the surface of a nonmagnetic topological insulator have been studied theoretically. A method has been demonstrated to control the Dirac point shift in the k space, which is a length measure of an exotic flat band appearing upon the formation of domain walls on the surface of antiferromagnetic topological insulator. The Dirac point shift is inversely proportional to the group velocity of electrons at the Dirac point and is proportional to the degree of localization of the topological state in the magnetic film. The shift is controlled by selecting a substrate with a certain work function. Particular systems have been proposed for the experimental study of flat band features in antiferromagnetic topological insulators.

Lateral distribution functions of particles in extensive air showers with the energy 
 eV recorded by ground-based and underground scintillation detectors with a threshold of @GeV at the Yakutsk array during the continuous observations from 1986 to 2016 have been analyzed using events with zenith angles θ ≤ 60°. Experimental functions have been compared to the predictions obtained with the QGSJet-01-d hadron interaction model by applying the CORSIKA code. The entire dataset indicates that cosmic rays consist predominantly of protons.

The memory effect in the form of hysteresis has been detected in the measured dependence of the intensity of the photon echo in YLiF4 and LuLiF4 samples with Er3+ impurity ions on the orientation, strength, and variation direction of the magnetic field. The prehistory of the location of a sample in the magnetic field with a certain direction and strength is written and stored for no less than 6 h at a temperature of 2 K. The effect crucially depends on the orientation of the optical axis of the sample with respect to the external magnetic field.

A scheme is proposed for a two-beam experiment on multi-petawatt laser systems aimed at searching for relativistic effects in electron tunneling from deep levels of multiply charged ions. It is shown that the most efficient relativistic ionization will occur in the field of a standing wave that arises in the case of counter-propagating beams. Estimates are given showing that the observation of relativistic effects during the ionization of -states of hydrogen-like ions with charge  is potentially possible at laser intensity in the beam overlap domain 1025 W/cm2.

A mathematical analogy between paraxial optics with two circular polarizations of light in a defocusing Kerr medium with positive dispersion, binary Bose–Einstein condensates of cold atoms in the phase separation regime, and hydrodynamics of two immiscible compressible liquids can help in theoretical search for unknown three-dimensional coherent optical structures. In this work, transversely trapped (by a smooth profile of the refractive index) light beams are considered and new numerical examples are presented, including a “floating drop,” a precessing longitudinal optical vortex with an inhomogeneous profile of filling with the second component, and the combination of a drop and a vortex filament. Filled vortices that are perpendicular to the beam axis and propagate at large distances have also been simulated.

Methods for the formation of hexagonal (2H) diamond from diamond polytypes under various types of deformation of the structure have been studied using density functional theory in the generalized gradient approximation. It has been established that the most appropriate method for the formation the structure of the 2H diamond polytype is the application of shear stresses >102.9 GPa along the [211] direction to the (111) planes of cubic diamond when pressures along the [111], [110], and [211] axes reach 21.6, 21.7, and 69.9 GPa, respectively. Raman and X-ray absorption spectra have also been calculated for various diamond polytypes. The analysis of calculated spectra shows that hexagonal diamond can be unambiguously identified if other diamond polytypes with nonzero hexagonality are absent in the system under study. In addition, Raman spectroscopy data and characteristic electron energy losses have been analyzed in order to determine the presence of 2H diamond in artificial or natural carbon compounds. It has been established that hexagonal diamond in the pure form has not yet been obtained and the structure of synthesized compounds is close to the structure of polytypes with a long lattice period or with a random packing of layers.

A joint system of equations based on the  superalgebra has been determined and its relation to the integrable Calodgero–Moser system of particles has been established.