Investigations of electroweak symmetry breaking mechanism for Higgs boson decays into four fermions

Models with extended Higgs boson sectors are of prime importance for investigating the mechanism of electroweak symmetry breaking for Higgs decays into four fermions and for Higgs-production in association with a vector bosons. In the framework of the Two-Higgs-Doublet Model using two scenarios obtained from the experimental measurements we presented next-to-leading-order results on the four-fermion decays of light CP-even Higgs boson, $h \rightarrow 4f$. With the help of Monte Carlo program Prophecy 4f 3.0, we calculated the values $\Gamma= \Gamma_{EW} /\left(\Gamma_{EW}+\Gamma_{SM}\right)$ and $\Gamma= \Gamma_{EW+QCD} /\left(\Gamma_{EW+QCD}+\Gamma_{SM}\right)$ for Higgs boson decay channels $H \rightarrow \nu_{\mu} \overline{\mu} e \overline{\nu_e}$, $\mu \overline{\mu} e \overline{e}$, $e \overline{e} e \overline{e}$. We didn't find significant difference when accounting QCD corrections to EW processes in the decay modes of Higgs boson. Using computer programs Pythia 8.2 and FeynHiggs we calculated the following values: $\sigma(VBH)BR(H\rightarrow ZZ)$ and $\sigma(VBF)BR(H \rightarrow WW)$ for VBF production processes, $\sigma(ggH)BR(H \rightarrow WW)$ and $\sigma(ggH)BR(H \rightarrow ZZ)$ for gluon fusion production process at 13 and 14 TeV and found good agreement with experimental data.Comment: 4 pages, 2 figure

Studying the resonance production cross-section of the heavy vectors within Heavy Vector Triplet model

In the context of TeV-scale extensions of the Standard Model both the experimental searches and the construction of phenomenological models for the new heavy bosons searches are used by us. Heavy particles predicted by a the Simplified Model constructed to describe only the on-shell resonance, have to be compared with LHC data. Heavy bosons have certain properties that can be calculated within the Heavy Vector Triplet model using the MadGraph computer program. We have calculated the production cross sections of heavy particles using the experimental constraints in the parameter space ($c_H$, $c_F$) imposed on the benchmark scenario. The nature of the functional dependence of the cross section at the basic parameters of the model on the mass of the new boson, as well as the mechanism for the heavy particle production is studied.Comment: 9 pages, 9 figure

Magnetic and spectral properties of multi-sublattice oxides SrY2O4:Er3+ and SrEr2O4

SrEr2O4 is a geometrically frustrated magnet which demonstrates rather unusual properties at low temperatures including a coexistence of long- and short-range magnetic order, characterized by two different propagation vectors. In the present work, the effects of crystal fields (CF) in this compound containing four magnetically inequivalent erbium sublattices are investigated experimentally and theoretically. We combine the measurements of the CF levels of the Er3+ ions made on a powder sample of SrEr2O4 using neutron spectroscopy with site-selective optical and electron paramagnetic resonance measurements performed on single crystal samples of the lightly Er-doped nonmagnetic analogue, SrY2O4. Two sets of CF parameters corresponding to the Er3+ ions at the crystallographically inequivalent lattice sites are derived which fit all the available experimental data well, including the magnetization and dc susceptibility data for both lightly doped and concentrated samples.Comment: 14 pages, 9 figure

Magnetocaloric effect in pyrochlore antiferromagnet Gd2Ti2O7

An adiabatic demagnetization process is studied in Gd2Ti2O7, a geometrically frustrated antiferromagnet on a pyrochlore lattice. In contrast to conventional paramagnetic salts, this compound can exhibit a temperature decrease by a factor of ten in the temperature range below the Curie-Weiss constant. The most efficient cooling is observed in the field interval between 120 and 60 kOe corresponding to a crossover between saturated and spin-liquid phases. This phenomenon indicates that a considerable part of the magnetic entropy survives in the strongly correlated state. According to the theoretical model, this entropy is associated with a macroscopic number of local modes remaining gapless till the saturation field. Monte Carlo simulations on a classical spin model demonstrate good agreement with the experiment. The cooling power of the process is experimentally estimated with a view to possible technical applications. The results for Gd2Ti2O7 are compared to those for Gd3Ga5O12, a well-known material for low temperature magnetic refrigeration.Comment: 6 pages, 4 figures, accepted versio

1H NMR spectroscopy study of structural water in rehydrated biocomposite of Spongilla lacustris freshwater demosponge origin

Biocomposites of sponge origin attract scientific attention due to their renewability as well as special properties. Dried skeletons of fresh water demosponge Spongilla lacustris represent unique kind of naturally occurring silica-chitin-based biocomposites with long history of their applications in dermatocosmetics. However, there is still a lack of knowledge on their physico-chemical properties in model systems. The aim of this work was to model drug systems based on S. lacustris powdered biocomposite, water and a hydrophobic medium, which served as an analog of an oil base. Both thermogravimetric analysis and 1H NMR spectroscopy study of structural water in rehydrated biocomposite lead to obtaining of interesting experimental data useful for preparation of biocosmetic products. © 2020, The Author(s).Deutsche Forschungsgemeinschaft, DFG: HE 394-3PPN/BEK/2018/1/00071Deutsche Forschungsgemeinschaft, DFGSächsisches Staatsministerium für Wissenschaft und Kunst, SMWK: 02010311This work was financially supported by German Research Foundation (DFG) Grant HE 394-3, SMWK Project 02010311 (Germany). M.W. is thankful for financial support from Polish National Agency for Academic Exchange (PPN/BEK/2018/1/00071) and support from Ministry of Science and Higher Education (Poland) as financial subsidy to PUT

Order by quenched disorder in the model triangular antiferromagnet RbFe(MoO4)2

We observe a disappearance of the 1/3 magnetization plateau and a striking change of the magnetic configuration under a moderate doping of the model triangular antiferromagnet RbFe(MoO4)2. The reason is an effective lifting of degeneracy of mean-field ground states by a random potential of impurities, which compensates, in the low-temperature limit, the fluctuation contribution to free energy. These results provide a direct experimental confirmation of the fluctuation origin of the ground state in a real frustrated system. The change of the ground state to a least collinear configuration reveals an effective positive biquadratic exchange provided by the structural disorder. On heating, doped samples regain the structure of a pure compound, thus allowing for an investigation of the remarkable competition between thermal and structural disorder

ОПЫТ ПРИМЕНЕНИЯ МЕТОДА ОПРЕДЕЛЕНИЯ МИНИМАЛЬНЫХ ИНГИБИРУЮЩИХ КОНЦЕНТРАЦИЙ В ЖИДКОЙ ПИТАТЕЛЬНОЙ СРЕДЕ ДЛЯ ВЫЯВЛЕНИЯ ЛЕКАРСТВЕННОЙ УСТОЙЧИВОСТИ НЕТУБЕРКУЛЕЗНЫХ МИКОБАКТЕРИЙ

Goal of the study: analysis of drug resistance of certain species of non-tuberculous mycobacteria through testing by minimum inhibitory concentrations on the fluid nutritional media.Materials and method: drug resistance of non-tuberculous mycobacteria was tested by the method of minimum inhibitory concentrations on the fluid nutritional media. 51 strains of non-tuberculous mycobacteria from the species of M. intracellulare, M. avium, M. kansasii, M. gordonae, M. fortuitum, M. abscessus were tested. The minimum inhibitory concentration of the drug for slow-growing non-tuberculous mycobacteria was defined using the panel of 13 drugs (SLOWMYCO) and for the fast-growing mycobacteria – the panel of 15 drugs RAPMYCO Sensititre (Trek Diagnostic System, Thermo Scientific, USA) was used. It was proved that the majority of tested fast growing mycobacteria were resistant to ceftriaxone, cefepime, cefoxitin but susceptible to amikacin; and slow growing non-tuberculous mycobacteria were susceptible to clarithromycin, linezolid and amikacin. Цель исследования: анализ лекарственной устойчивости некоторых видов нетуберкулезных микобактерий (НТМ) методом определения минимальных ингибирующих концентраций в жидкой питательной среде.Материалы и методы: лекарственную устойчивость НТМ определяли методом минимальных ингибирующих концентраций в жидкой питательной среде. Исследован 51 штамм НТМ, относящийся к видам M. intracellulare, M. avium, M. kansasii, M. gordonae, M. fortuitum, M. abscessus. Минимальную ингибирующую концентрацию препаратов для медленнорастущих НТМ определяли с использованием панели из 13 препаратов (SLOWMYCO), а для быстрорастущих микобактерий – из 15 препаратов RAPMYCO Sensititre (Trek Diagnostic System, Thermo Scientific, США). Показано, что большинство исследованных быстрорастущих НТМ нечувствительны к цефтриаксону, цефепиму, цефокситину, но чувствительны к амикацину, а медленнорастущие НТМ чувствительны к кларитромицину, линезолиду и амикацину.