Search

The cosmological observations of gravitational lenses, cosmic microwave background, rotation speed of stars in galaxies confirm the existence of about 27% dark matter in the Universe. The nature of these particles is unknown, however, there are theoretical models Beyond the Standard Model (BSM), such as superstrings and D-branes, which predict new particles of type WIMPs, dilatons, axions, etc. Experiments to search for such particles are being actively carried out both in space and on modern accelerators, and unambiguous information regarding the type of particles has not yet been identified., Comment: 3 pages, 5 figures

The character of the behavior of the RGE constant on a certain energy interval is studied and polynomial interpolation is carried out to obtain an analytic function describing the RGE constant in QCD. A graphical description of the nature of the dependence of the beta function and the interaction constant is carried out and it is shown that a good agreement with the theoretical predictions of the asymptotic freedom is observed only in the energy region of 3800-4000 GeV., Comment: 5 pages, 5 figures

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 figures

We studied the properties of the MSSM Higgs bosons, h and H through the decay into b-quarks in associated production with a top-quark pair. There was used the tree-level Higgs sector described by two parameters M$_A$ and tan$\beta$ and found their optimal values according to experimental data of ATLAS detector. Using the restricted parameter space we calculated cross sections of associated $t\bar{t}h(H)$ production at 13 and 14 TeV, the corresponding kinematical cuts, mass distributions and Branching Ratios of h and H decays into $b\bar{b}$ quark pair., Comment: 6 pages, 7 figures

We considered the new signature of a charged Higgs boson, $pp\rightarrow H^{\pm}h\rightarrow W^{\pm}hh$, which is almost background free as the promising to study of supersymmetry at the LHC with both $\sqrt{s} = 13$ TeV and $\sqrt{s}= 14$ TeV. In the framework of MSSM model we used the latest theoretical parameter space, which is consistent with the experimental constraints from Large Hadron Collider and direct or indirect searches. In the surviving regions with the help of Pythia 8.3 and Feynhiggs programs it was found that production cross sections, $\sigma(pp\rightarrow H^{\pm}h)$, and Branching Ratios, $BR(H^{\pm}\rightarrow W^{\pm}h)$, are the largest at Benchmark Points 4 and 14 correspondingly., Comment: 5 pages, 4 figures

In the framework of PYTHIA8.2 program we considered p-Pb and p-Au heavy ion collisions at the energy of 5.02 TeV and 8 TeV. The advantage of this program is in the combining of several nucleon-nucleon collisions into one heavy ion collision, based on phenomenological treatment of a hadron as a vortex line in a color superconducting medium, the consistent treatment of the central rapidity region with improvements of Glauber-like model where diffractive excitation processes are taken into account. We have considered the influence of impact parameter correlations on the production cross sections of p-Pb and p-Au processes to estimate the influence of hard and soft subprocesses on basic hadronic final-state properties in proton-ion collisions. Using these characteristics based on semi-hard multiparton interaction model we received the transverse momentum and rapidity distributions of K-meson and Lambda baryon at the energy of 5.02 TeV and 8.14 TeV., Comment: 12 pages, 11 figures, Materials have been accepted in EPS-HEP2021 conference

The discovery in July 2020 of fully-charm tetraquark led to the need for its theoretical explanation. For investigation of such complex four-quark formation, the modern mathematical apparatus of the theory of derived categories is used. By representing diquarks as solitonic objects in terms of sheaves, one can explain the measured mass of the broad resonance of fully-charm tetraquarks consisting of di-charmonia., Comment: 8 pages, 4 figures, materials are presented in the Proceedings of the 1st International Scientific and Practical Conference "Theory and Practice of Science: Key Aspects". (February 19-20, 2021). Rome, Italy

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 figure

The searches for heavy neutral and charged Higgs bosons are performed through the calculations of production cross sections using MadGraph5aMC@NLO program with ansatz of Yukawa coupling and the restricted parameter space connected with LHC Run 2 data. The searches for heavy resonances are performed in the framework of 2HDM model over the mass range 0.1 - 1 TeV for the $pp\rightarrow At\bar{b}$, $pp\rightarrow H^{+}b\bar{t}$ , $pp\rightarrow H^{+}t\bar{t}$ , $pp\rightarrow HHZ$ decay modes. The presented data demonstrate the jump in the production cross section of $H^{+} b\bar{t}$ and $HHZ$ production processes in the mass range of 100-200 GeV and 100-300 GeV accordingly at energy of 14 TeV., Comment: 7 pages, 5 figures

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 figures

Heavy ion collisions provide a unique probe of the quark-gluon plasma properties. The role of partonic degrees of freedom in p-Pb collisions at $\sqrt{s_{NN}}$ = 5 TeV by studying the production cross section is studied. Experimental observable like the number of K$_S$ mesons is sensitive to the kinematic properties of the reaction. Our results demonstrate the importance of angular distribution for the partonic degrees of freedom in hadronization process., Comment: The data of other authors (Vassiliev, Bratkovskaya), with which we are comparing our results, is not yet published and they are claiming on withdrawal of this article

In the paper is presented computer modelling of BSM physics, such as Dark matter candidates, di-jet resonances and new Higgs bosons with the help of MCFM program., Comment: 10 pages, 9 figures

The paper is connected with searches for the Ramond-Ramond charge of D branes in the presence of B field. The consideration of B field inclusion is an important physical and mathematical unsolved problem, which is connected with K group calculations of twisted bundles. Considered two cases of vector bundles, Azumaya and Rosenberg algebras and analyzed their K group realization., Comment: 7 pages, materials were presented at the International Conference "Morse theory and its applications", Kyiv, Ukraine, September 25-28, 2019

F-theory, as a 12-dimensional theory that is a contender of the Theory of Everything, should be compactified into elliptically fibered threefolds or fourfolds of Calabi-Yau. Such manifolds have an elliptic curve as a fiber, and their bases may have singularities. We considered orbifold as simplest non-flat construction. Blow up modes of orbifold singularities can be considered as coordinates of complexified Kahler moduli space. Quiver diagrams are used for discribing D-branes near orbifold point. In this case it is possible to calculate Euler character defined through $\mbox{Ext}^i(A,B)$ groups and coherent sheaves $A, B$ over projective space, which are representations of orbifold space after blowing up procedure. These fractional sheaves are characterized by $Q_0$, $Q_2$ and $Q_4$ Ramon-Ramon charges, which have special type, calculated for $C^3/Z_3$ case. BPS central charge for $C^3/Z_3$ orbifold is calculated through Ramon-Ramon charges and Picard-Fuchs periods., Comment: 8 pages, 5 figures, materials are presented in XII International Algebraic Conference in Ukraine (July 02-06, 2019) Vinnytsia, Ukraine

The problems of Standard Model as well as questions related to Higgs boson properties led to the need for modeling of ttH associated production and Higgs boson decay to top quark pair within the MSSM model. With the help of computer programs MadGraph, Pythia and Delphes and using the latest kinematic cuts taken from experimental data obtained at the LHC we predicted the masses of MSSM Higgs bosons, A and H., Comment: 8 pages, 9 figures, Materials are presented to New Trends in High-Energy Physics Conference, Odessa, Ukraine, 2019

The problem with Bekenstein-Hawking entropy of black hole can be resolved with quantum gravity theory with Dp-branes as supergravity solutions of type IIB string theory. Dp-brane solutions of type IIB are a direct analog of the Schwarzschild charged hole, so called black p-branes. The coincidence of the black p-brane metrics and ten-dimensional metrics of N-parallel D3-branes was used from the viewpoint of the Azumaya structure on D-branes connected with deformation of the classical moduli space. Applying Rosenberg theorem we can classify Hilbert spaces of N coinciding Dp-branes as vector bundles through K-functor., Comment: 7 pages, 6 figures, materials presented in StringPheno18 conference

The article is devoted to the searches for new particles predicted by physics beyond the Standard Model through the b-tagging algorithm. The dependence of b-tagging efficiency on the jet identification, impact parameter identification, secondary vertex identification, kinematic cuts is studied with the help of computer programs Pythia 8.2 and Fastjet 3.3.0. The selection criteria for kinematic parameters, their ratios for an optimal result on the reconstruction of the vertices of heavy particles are found., Comment: 11 pages, 10 figures

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 were calculated the production cross sections for Kaluza-Klein particles at various energies at the LHC. The generation of monojet events from scalar graviton emission was considered for number of extra dimensions, n=2, 4, 6, for the energy at the LHC 14 TeV. Also are studied the graviton production processes through the gluon-gluon, quark-gluon and quark-quark fusion processes and found some periodicity in the behavior of the graviton mass spectrum. Within Randall-Sundrum scenario were calculated $\sigma\times$ Br for production process of massive graviton, gg $\rightarrow$ $G^{*}$, and the most probable processes of graviton decay at 13 TeV, 14 TeV and 100 TeV., Comment: 16 pages, 9 figures

Using the latest experimental data, performed by ATLAS Collaboration and within the framework of the Minimal Supersymmetric Standard Model, we presented the calculations for cross sections times branching fractions, $\sigma\times Br$, as a functions of the CP-even, H, Higgs boson mass, CP-odd, A, Higgs boson mass and charged, H$^{\pm}$, Higgs boson mass. Using the restricted parameter set, received from the hMSSM+HDECAY and "low-tb-high" scenarios, with the help of the computer programs SOFTSUSY, Prospino and SusHi, we received the large values of $\sigma\times Br$ for A and H bosons at tan$\beta$=2 for the planned 14 TeV at the LHC and found the large $\sigma\times Br$ at tan$\beta$=30 for charged Higgs boson. The obtained results are of experimental interest as they are connected with the experimental searches for new physics beyond the Standard Model at the LHC., Comment: 12 pages, 14 figures

Within the framework of the cosmological theory of the Big Bang, F-theory that unifies all four types of fundamental interactions is represented. Among the most exciting predictions of physics beyond the Standard Model is the assumption of the space of extra dimensions that solves the hierarchy problem. With the presence of this extra dimensions are connected the searches for Kaluza-Klein partners of gravitons, gauge bosons and microscopic black holes at the LHC. In the framework of F-theory, Calabi-Yau fourfold is considered as a space of extra dimensions. We study the duality between the F-theory compactified on the K3-surface and $E_8\times E_8$ heterotic string compactified on the torus, $T^2$. The set of BPS states corresponding to the Calabi-Yau fourfolds, which has either an elliptic curve or a K3-fibration as a layer, is studied in the aspect of correspondence to the KK modes of the M-theory on $R^8\times T^2 \times S^1 / Z_2$. The singularities of the moduli space of the Calabi-Yau fourfold make it possible to observe massive KK modes, the masses of which are obtained from the M-theory of supergravity. The result is of interest for a theoretical understanding of the KK modes, the experimental searches for which are carried out at the LHC., Comment: 6 pages, 5 figures

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, 2017

The duality between $E_8\times E_8$ heteritic string on manifold $K3\times T^2$ and Type IIA string compactified on a Calabi-Yau manifold induces a correspondence between vector bundles on $K3\times T^2$ and Calabi-Yau manifolds. Vector bundles over compact base space $K3\times T^2$ form the set of isomorphism classes, which is a semi-ring under the operation of Whitney sum and tensor product. The construction of semi-ring $Vect\ X$ of isomorphism classes of complex vector bundles over X leads to the ring $KX=K(Vect\ X)$, called Grothendieck group. As K3 has no isometries and no non-trivial one-cycles, so vector bundle winding modes arise from the $T^2$ compactification. Since we have focused on supergravity in d=11, there exist solutions in d=10 for which space-time is Minkowski space and extra dimensions are $K3\times T^2$. The complete set of soliton solutions of supergravity theory is characterized by RR charges, identified by K-theory. Toric presentation of Calabi-Yau through Batyrev's toric approximation enables us to connect transitions between Calabi-Yau manifolds, classified by enhanced symmetry group, with K-theory classification., Comment: 8 pages, presented for International conference "Geometry in Odessa 2016"

F-theory, as Theory of Everything is compactified on Calabi-Yau threefolds or fourfolds. Using toric approximation of Batyrev and mirror symmetry of Calabi-Yau manifolds it is possible to present Calabi-Yau in the form of dual integer polyhedra. With the help of Gelfand, Zelevinsky, Kapranov algorithm were calculated the numbers of BPS-states in F-theory, and by application of Tate algorithm were determined the enhanced symmetries. As the result, any integral dual polyhedron representing a Calabi-Yau manifold, is characterized by its own set of topological invariants - the numbers of BPS states, whose central charges are classified by enhanced symmetries., Comment: 8 pages, 1 figure, iopams.sty

Search for supersymmetry is carried out in the framework of the Minimal Supersymmetric Standard Model (MSSM). Using the software programs SOFTSUSY and PROSPINO, the mass spectrum and the production cross-sections of superpartners are calculated. The results obtained are of importance for searching the new physics at the LHC., Comment: 11 pages, 2 figures

We study D-branes on Calabi-Yau threefolds, which are realized through the blowing up the singularity of orbifold. This D-branes are represented as sheaves, which can be stable or unstable, what is connected with the transition in the Teichm$\ddot{u}$ller space. Using the derived category of McKay quiver representations, which describe D-branes as quivers and open superstrings between them by Ext groups, we can represent Higgs multiplets by the moduli space of an open superstring, connecting two McKay quivers. Through the equivalence between the derived category of coherent sheaves and triangulated category of distinguished triangles over the abelian category of McKay quivers we can associate D-branes with quivers or with sheaves, defined on Calabi-Yau. After the dimensional reduction of the ten-dimensional space-time we can receive matter content of the four-dimensional space-time. Thus, a higher-dimensional breaking mechanism is associated with four-dimensional GUT Higgs multiplets and symmetry breaking higgs mechanism., Comment: 6 pages, 4 figures, jheppub.sty. arXiv admin note: text overlap with arXiv:hep-th/0403166 by other authors

The Nakamura's algorithm is applied to compute the Hilbert scheme for the D-brane model 1/13(1,2,10)., Comment: 9 pages, LATEX

It is shown that the matter content of F-theory compactifications on elliptic Calabi-Yau threefolds is encoded in the Gromov-Witten invariants., Comment: 7 pages, LATEX

The enhanced gauge groups in F-theory compactified on elliptic Calabi-Yau fourfolds are investigated in terms of toric geometry., Comment: 7 pages, LATEX

The sine-Gordon model is applied to describe the multiphonon giant resonances., Comment: 5 pages, LATEX, 1 figure

The spectra of BPS states in F-theory on elliptic fibred fourfolds are investigated., Comment: 7 pages, LATEX