An Investigation of Signal Kinematical Region to Study Standard Model Higgs Boson Properties in the H → WW* → ℓvℓv Decay Channel in the ATLAS Experiment at the Large Hadron Collider at 13 TeV

A signal kinematical region is analyzed by the Higgs Boson Working Group (HWW) within the framework of a study of the Standard Model Higgs boson properties in the H → WW* → evεv decay channel in the ATLAS experiment on the Large Hadron Collider (LHC). The analysis is based on the full statistics of proton-proton collision data during exposures in 2015–2016 at the center-of-mass energy of 13 TeV. As compared to our previous analysis, the reconstruction software is updated and the simulation accuracy of backgrounds is improved. Events taken at low and high LHC luminosity are studied separately. In addition, the kinematics at the later stages of event selection is investigated in detail and systematic uncertainties are fully estimated. It is shown that the Monte Carlo modeling satisfactorily describes the experimental data at different selection stages. Kinematic distributions for hadron jets are studied also in the Z-boson control region, where the acquired data reach the order of ten million events. As compared to the previous investigation, the modeling accuracy of Z and background processes is noticeably improved, and events at low and high LHC luminosities are studied separately. Furthermore, all systematic uncertainties related to jets are estimated as well. As a whole, good agreement between experimental results and Monte Carlo simulation data is observed. No problems that would be caused by high luminosity are observed.

     

Influence of the ferromagnetic structure on the speed of propagation of magnetoelastic vibrations

The effect of thermomagnetic treatment temperature on the speed of magnetoelastic vibrations propagating in aFe _81.5 B _13.5 Si ₃ C ₂ metal alloy is investigated. A minimum is found in the plot of the dependence of the speed of magnetoelastic vibrations on the thermomagnetic treatment temperature. No minimum is observed in this dependence for amorphous metal alloys treated without magnetic field. It is found that the dependences of the speed of magnetoelastic vibrations on the external magnetic field differ for samples treated differently. The results obtained are explained based on concepts of reorganization of the domain structure of the samples under study. Irkutsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 46–49, September, 1999.     

Solution of one problem of nonlinear adsorption kinetics by the method of lines

The method of lines is constructed and proved for numerical solution of a nonlinear initial-boundary-value problem of parabolic type describing the adsorption of a substance from an aqueous solution of bounded volume by a spherical adsorbent. The method is developed under natural assumptions on the smoothness of the solution of the original problem. The rate of convergence of the method depends on the smoothness of the initial function and is of order O(h) if v₀(x) 0, O(h^1/2) if v₀(x) C¹[0, 1], and 0(|v ₀(x)|W ₂ ¹ (O,h)).Translated from Vychislitel'naya i Prikladnaya Matematika, No. 63, pp. 24–30, 1987.     

Rate of convergence of the method of lines for the nonlinear parabolic integrodifferential equation describing a photon recycling diode

We consider the Dirichlet problem and the mixed boundary-value problem for a nonlinear integro-differential equation of a parabolic type, which provides a mathematical model of the various modes in a photon-recycling semiconductor diode. The existence of the mixed derivative ²u/tx is proved for the solution of these problems. Method-of-lines schemes are constructed. An O(h) rate of convergence bound is established for the equation with nonlinear integral and differential components and an O(h²) bound for the equation with a nonlinear integral part.Kiev University. Translated from Vychislitel'naya i Prikladnaya Matematika, No. 74, pp. 21–31, 1992;     

On Terwilliger graphs with µ = 4

A Terwilliger graph is an incomplete connected graph in which the intersection of the neighborhoods of any two vertices at distance 2 is a µ-clique for some constant µ. The local structure of Terwilliger graphs with µ = 4 is described.     

Defects of colloidal crystals

Reasons for the appearance of defects of various types in crystalline colloidal structures formed during the self-organization of the ensembles of spherical nanoparticles are analyzed using lyosols of metal nanoparticles stabilized with polymers as examples. Quantitative characteristic of the degree of imperfection of colloidal crystals is proposed and the procedures for the minimization of the degree of imperfection are discussed. Order-disorder phase transitions of colloidal crystals are studied.     

Spin correlations and a mesoscopic structure in Ni-Mn-Ga

The mesoscopic structures of the Heusler alloys Ni_49.1Mn_29.4Ga_21.5 and Ni₂MnGa are studied by small-angle polarized neutron scattering in the temperature range 15 < T < 400 K. The characteristic temperatures of phase transformations (ferromagnetic, martensitic, and premartensitic transformations) and the characteristic sizes of mesoscopic inhomogeneities in them have been determined. Differences in the spin dynamics of these phases and magnetic-nuclear interference upon neutron scattering have been revealed. The evolutions of the mesoscopic structures in the nonstoichiometric and stoichiometric alloys are found to be substantially different.