The study of the extended Higgs boson sector within 2HDM model

Consideration of the latest experimental data on the searches for extended sector of Higgs bosons produced at the LHC at a center-of-mass energy of 13 TeV, allows for computer modeling of the properties of supersymmetric particles within 2HDM model. The experimental restrictions on model parameters accounted in FeynHiggs code that is implemented in SusHi program, gave us the possibility to calculate the cross sections and branching fractions for three mechanisms of production and decay of Higgs bosons: 1) pp$\rightarrow H\rightarrow\tau\tau$, 2) pp$\rightarrow A\rightarrow Zh\rightarrow llbb$, 3) pp$\rightarrow H\rightarrow hh\rightarrow bb\tau\tau$ at a center-of-mass energy of 14 TeV. The considered computer modelling make it possible to draw conclusions about the need to take into account the b-associated production process of Higgs bosons for fermionic decay channel at large values of tan$\beta$. Differential cross sections with respect to the Higgs transverse momentum $p_t$ and pseudorapidity $\eta$ are calculated and the peculiarities of the kinematics of the Higgs boson decay products are recognized.Comment: 18 pages, 14 figures, presented at XV Conference of High energy physics, Kharkov, 21-24 March, 201

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

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

Searches for Massive Graviton Resonances at the LHC

The Standard Model problems lead to the new theories of extra dimensions: Randall-Sundrum model, Arkani-Hamed-Dimopoulos-Dvali model, and TeV-1 model. In the framework of these models, with the help of computer program Pythia8.2, the production cross sections for Kaluza-Klein particles at various energies at the LHC were calculated. The generation of monojet events from scalar graviton emission was considered for number of extra dimensions (n=2, 4, and 6) for the energy at the LHC 14 TeV. The graviton production processes through the gluon-gluon, quark-gluon, and quark-quark fusion processes are also studied and some periodicity was found in the behavior of the graviton mass spectrum. Production cross sections multiplied by branching fractions were calculated for the massive graviton, G, within Randall-Sundrum scenario and the most probable processes of graviton decay at 13 TeV, 14 TeV, and 100 TeV were counted

Decay width modeling of Higgs boson within THDM model

As part of the search for new physics beyond the Standard Model, we chose the determination of the Higgs boson decay width as one of the least experimentally determined values. The decay widths into the four fermions of the lightest and heaviest CP-even Higgs bosons of the THDM model were calculated, taking into account QCD and electroweak corrections in the NLO approximation. To achieve this goal, the program Monte Carlo Prophecy 4f with special scenarios of parameters, 7B1 and 5B1 were used. It was found that the decay width of the heavier CP-even Higgs boson, H differs from H$_{SM}$ by 1227.93 times and changes to a negative value when deviating from the standard scenarios. Scale factors k$^2_{Z}$ and k$^2_{W}$ showed the predominance of the associated with Z boson production cross section of CP-even Higgs boson over the associated with W production cross section.Comment: 10 pages, 1 figur

Phosphorodiamidates as a Promising New Phosphate Prodrug Motif for Antiviral Drug Discovery: Application to Anti-HCV Agents

We herein report phosphorodiamidates as a significant new phosphate prodrug motif. Sixty-seven phosphorodiamidates are reported of two 6-O-alkyl 2′-C-methyl guanosines, with significant variation in the diamidate structure. Both symmetrical and asymmetric phosphorodiamidates are reported, derived from various esterified amino acids, both d and l, and also from various simple amines. All of the compounds were evaluated versus hepatitis C virus in replicon assay, and nanomolar activity levels were observed. Many compounds were noncytotoxic at 100 μM, leading to high antiviral selectivities. The agents are stable in acidic, neutral, and moderately basic media and in selected biological media but show efficient processing by carboxypeptidases and efficiently yield the free nucleoside monophosphate in cells. On the basis of in vitro data, eight leads were selected for additional in vivo evaluation, with the intent of selecting one candidate for progression toward clinical studies. This phosphorodiamidate prodrug method may have broad application outside of HCV and antivirals as it offers many of the advantages of phosphoramidate ProTides but without the chirality issues present in most cases