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A. B. Arbuzov

Publications and source records attributed to A. B. Arbuzov.

At least 19 recordsLinked to original sources

SNe Ia in Standard and Conformal Cosmological Models

This article demonstrates the classical equivalence between standard and conformal cosmological models regarding the apparent luminosity of type Ia supernovae. We show that previous claims of observational discrepancies stem from differing interpretations of physical quantities when transitioning between Einstein and Jordan frames. Specifically, we establish that in the conformal picture, SNe Ia are not "standard candles" in the conventional sense because their absolute luminosity depends on redshift due to variations in local measurement units.

gr-qc↗

Vacuum Polarization Effects During the Reheating Epoch

Quantum effects in the era of reheating of the universe after inflation are considered. A semiclassical approach to gravity theory is applied within Starobinsky's inflationary model with backreaction. Some subtleties associated with accounting for quantum effects in the one-loop approximation are clarified. An estimate of the contribution of vacuum polarization in the stress-energy tensor of matter fields to the cosmological particle creation due to the scalaron decay is presented.

gr-qc↗

On axion properties in the 3-3-1 model with $U(1)_{B-L}$ and Peccei-Quinn symmetries

The Peccei-Quinn ($PQ$) mechanism is applied to the $\mathrm{SU(3)_c \otimes SU(3)_L \otimes U(1)_X}$ model with $U(1)_{B-L}$ symmetry. The structures in the $PQ$ charges of all fermions and scalar fields in the model are investigated by applying the invariant condition under the symmetry group transformations on all Yukawa interaction terms. All defined $PQ$ charges depend just on the $PQ$ charge of the complex singlet scalar field which causes the $U(1)_{PQ}$ spontaneous symmetry breaking in the model. The mixing and mass hierarchy in the scalar sector of the model are studied in detail. The constraints on the $PQ$ charges and imaginary parts of scalars are derived. It is shown that only neutral scalar fields carry $PQ$ charges while charged ones do not. As the result, the physical state of axion which obeys the invariance under $\mathrm{SU(3)_L \otimes U(1)_X}$ and $PQ$ transformations, is a linear combination of all imaginary parts associated with the $X$ charges of scalar triplets. The anomaly axion-fermion interactions are presented. Explicit expressions for axion and light Standard Model (SM) like Higgs boson are shown. Mass of the axion and its coupling to photon are derived. The decays of the SM-like Higgs boson into a pair of either charged leptons or bottom quarks are presented and constrained. The triple-coupling axion-photon-photon arisen from kinetic terms of scalar fields is derived. Hence, the decay of axion into a pair of photons consists of two parts: the first is related to the anomaly coupling and the second is come from kinetic terms of scalar fields. The result shows that the new contribution can be helpful for searching axion with mass at hundred keV.

hep-ph↗

Higher-order NLO initial state QED radiative corrections to $e^+e^-$ annihilation revisited

Radiative corrections due to initial state radiation in electron-positron annihilation are calculated within the QED structure function approach. Results are shown in the next-to-leading logarithmic approximation up to $O(α^4 L^3)$ order, where $L=\ln(s/m_e^2)$ is the large logarithm. Several mistakes in previous calculations are corrected. The results are relevant for future high-precision experiments at $e^+e^-$ colliders.

hep-ph↗

On the choice of variable for quantization of conformal GR

The possibility of using spin connection components as basic quantization variables of a conformal version of General Relativity is studied. The considered model contains gravitational degrees of freedom and a scalar dilaton field. The standard tetrad formalism is applied. Properties of spin connections in this model are analyzed. Secondary quantization of the chosen variables is performed. The gravitational part of the model action turns out to be quadratic with respect to the spin connections. So at the quantum level the model looks trivial, i.e., without quantum self-interactions. Meanwhile the correspondence to General Relativity is preserved at the classical level.

gr-qc↗

SANC Monte Carlo programs for small-angle Bhabha scattering

Luminosity monitoring at $e^+e^-$ colliders is investigated using SANC Monte Carlo event generator ReneSANCe and integrator MCSANC for simulation of Bhabha scattering at low angles. Results are presented for center-of-mass energies of the Z boson resonance and 240 GeV for the conditions of typical luminosity detectors. It is shown that taking into account bremsstrahlung events with extremely low electron scattering angles is relevant to match the precision tags of the future electron-positron colliders.

hep-ph↗

Higher-order NLO radiative corrections to polarized muon decay spectrum

Higher-order QED radiative corrections to muon decay spectrum are evaluated within the QED structure function approach in the next-to-leading order logarithmic approximation. New analytical results are given in the $\mathcal{O}\left(α^3 \ln^2(m_μ^2/m_e^2)\right)$ order. Earlier results in $\mathcal{O}\left(α^2 \ln^1(m_μ^2/m_e^2)\right)$ and $\mathcal{O}\left(α^3 \ln^3(m_μ^2/m_e^2)\right)$ orders are partially corrected. Numerical estimates of different contributions are presented.

hep-ph↗

Decays of radially excited vector mesons $ρ'$ and $ω'$ in the extended NJL model

The decay widths of $ρ' \to ππ, ωπ, ρη$, $ω' \to ρπ, ωη$ and $π' \to ρπ$ are recalculated within the extended NJL quark model. It is shown that the mass of $ρ'(1450)$ meson in the derived in the NJL model agrees with the one given in Particle Data Group tables but significantly deviates from the recent result of CMD-3 collaboration. Comparisons with earlier theoretical results are presented.

hep-ph↗

Unpolarized QED parton distribution functions in NLO

Perturbative solutions for unpolarized QED parton distribution and fragmentation functions are presented explicitly in the next-to-leading logarithmic approximation. The scheme of iterative solution of QED evolution equations is described in detail. Terms up to $\mathcal{O}(α^3L^2)$ are calculated analytically, where $L=\ln(μ_F^2/m_e^2)$ is the large logarithm which depends on the factorization energy scale $μ_F\gg m_e$. The results are process independent and relevant for future high-precision experiments.

hep-ph↗

Decays of CP-even Higgs bosons $H \rightarrow l_il_j$ in a 3-3-1 model with neutral leptons

The 3-3-1 model with neutral leptons contains four CP-even Higgs bosons when some constraints are imposed on the Higgs potential. Two Higgs bosons of this type are identified with the corresponding ones in the Two-Higgs-Doublet model (2HDM), an other being more massive does not couple with similar particles contained in the Standard Model (SM). The remaining particle is assumed to have no lepton-flavor-violating couplings. The contributions at one-loop order to $\mathrmΓ(\mathrm{H}\rightarrow l_il_j)$$(H \equiv h^0_1,h^0_2,h^0_3)$ come mainly from neutral leptons leading them to depend very strongly on mass of charged Higgs boson, masses and the mixing matrix ($V^L_{ab}$) of the neutral leptons. The numerical investigated results of $\mathrmΓ(\mathrm{H}\rightarrow l_il_j)$ in the spatial regions satisfying the experimental limit of lepton-flavor-violating decays of charged leptons (cLFV) indicate that the signal of SM-like Higgs boson ($\mathrmΓ(h^0_1\rightarrow l_il_j)$) approaches the upper bound of the experimental limit and $\mathrmΓ(\mathrm{H}\rightarrow l_il_j)$ can take large values in the case of $V^L_{ab} = U^L_{ab}(π/4,π/4,-π/4)$ and smaller in the case of $V^L_{ab} = U^L_{ab}(π/4,0,0)$. Further, some distinct properties of $\mathrmΓ(h^0_2\rightarrow l_il_j)$ and $\mathrmΓ(h^0_3\rightarrow l_il_j)$ are also discussed.

hep-ph↗

Conceptual design of the Spin Physics Detector

The Spin Physics Detector, a universal facility for studying the nucleon spin structure and other spin-related phenomena with polarized proton and deuteron beams, is proposed to be placed in one of the two interaction points of the NICA collider that is under construction at the Joint Institute for Nuclear Research (Dubna, Russia). At the heart of the project there is huge experience with polarized beams at JINR. The main objective of the proposed experiment is the comprehensive study of the unpolarized and polarized gluon content of the nucleon. Spin measurements at the Spin Physics Detector at the NICA collider have bright perspectives to make a unique contribution and challenge our understanding of the spin structure of the nucleon. In this document the Conceptual Design of the Spin Physics Detector is presented.

hep-ex↗

Electroweak effects in polarized muon-electron scattering

A theoretical description of elastic polarized muon-electron scattering is presented. Complete one-loop electroweak radiative corrections are calculated with taking into account the exact dependence on the muon mass. The effects due to some higher order corrections and the electroweak scheme dependence are analyzed. The case of longitudinally polarized fermions in the initial state is investigated. Analytical results are derived with the help of the SANC system. Numerical results are presented for unpolarized and polarized cross sections. Calculations are realized in the Monte Carlo integrator MCSANCee and generator ReneSANCe which allow the implementation of any experimental cut used in the analysis of elastic $μ- e$ scattering data.

hep-ph↗

Fixing the vector coupling constant $g_ρ= 5.0$ in the NJL model and final-state interactions in processes $ρ\to e^+e^-[μ^+μ^-]$, $ρ\to π^+π^-$, $τ\to π^-π^0ν_τ$, and $e^+e^-\toπ^+π^-$

The possibility to use the width of the decay $ρ\to e^{+}e^{-}$ to fix the input parameter $g_ρ=5.0$ of the $SU(2) \times SU(2)$ chiral-symmetric Nambu--Jona-Lasinio model is discussed. It is shown that for a consistent simultaneous description of the processes $ρ\to e^{+}e^{-}$, $ρ\to π^{+}π^{-}$, $τ^{-} \to π^{-}π^{0} ν_τ$, and $e^{+}e^{-} \to π^{+}π^{-}$ can be constructed. Taking into account the interaction of pions in the final state appears to be important. The obtained theoretical results for the considered processes are in a satisfactory agreement with experimental data.

hep-ph↗

Processes $τ^- \to π^- π^0 ν_τ$ and $e^{+}e^{-} \to π^{+} π^{-}$ in the chiral NJL model with final state interactions taken into account

The processes $τ^- \to π^- π^0 ν_τ$ and $e^{+}e^{-} \to π^{+} π^{-}$ are considered within the chiral Nambu--Jona-Lasinio model with taking into account the pion final state interactions beyond the leading $1/N_c$ approximation. The contribution of the loop correction caused by a $ρ$ meson exchange between the pions, which gives the main contribution in the P-wave channel, is caclulated. The results for both processes are in a satisfactory agreement with experimental data.

hep-ph↗

On the scale hierarchy in radiative symmetry breaking

The emergence of a scale hierarchy in the case of spontaneous radiative breaking of conformal symmetry is discussed using the example of a simple quantum field theory model. The Coleman-Weinberg mechanism is implemented in the one-loop approximation of the effective potential of a scalar field interacting with a fermion field. The emergence of a hierarchy between the renormalization scale and the magnitude of the scalar field vacuum expectation value is shown. An effective model in the vicinity of the effective potential minimum is constructed, and absence of a direct renormalization group transition to the original theory is established. It is shown that effective model parameters measurement in the infrared region allows us to determine the scale that limits the applicability region of the model.

hep-ph↗

Theory for the FCC-ee : Report on the 11th FCC-ee Workshop

The Future Circular Collider (FCC) at CERN, a proposed 100-km circular facility with several colliders in succession, culminates with a 100 TeV proton-proton collider. It offers a vast new domain of exploration in particle physics, with orders of magnitude advances in terms of Precision, Sensitivity and Energy. The implementation plan foresees, as a first step, an Electroweak Factory electron-positron collider. This high luminosity facility, operating between 90 and 365 GeV centre-of-mass energy, will study the heavy particles of the Standard Model, Z, W, Higgs, and top with unprecedented accuracy. The Electroweak Factory $e^+e^-$ collider constitutes a real challenge to the theory and to precision calculations, triggering the need for the development of new mathematical methods and software tools. A first workshop in 2018 had focused on the first FCC-ee stage, the Tera-Z, and confronted the theoretical status of precision Standard Model calculations on the Z-boson resonance to the experimental demands. The second workshop in January 2019, which is reported here, extended the scope to the next stages, with the production of W-bosons (FCC-ee-W), the Higgs boson (FCC-ee-H) and top quarks (FCC-ee-tt). In particular, the theoretical precision in the determination of the crucial input parameters, alpha_QED, alpha_QCD, M_W, m_t at the level of FCC-ee requirements is thoroughly discussed. The requirements on Standard Model theory calculations were spelled out, so as to meet the demanding accuracy of the FCC-ee experimental potential. The discussion of innovative methods and tools for multi-loop calculations was deepened. Furthermore, phenomenological analyses beyond the Standard Model were discussed, in particular the effective theory approaches. The reports of 2018 and 2019 serve as white papers of the workshop results and subsequent developments.

hep-ph↗

Forward-backward asymmetry in $e^+e^-$ annihilation into pions or kaons revisited

Forward-backward (charge) asymmetry in the processes of $e^+e^-$ annihilation into a pair of charged pseudoscalar mesons is recalculated in the one-loop approximation. The exact dependence on the meson masses is taken into account. Results known in the literature are partially corrected. The bulk of the charge asymmetry appears due to double-photon exchange in $s$ channel. Experimental studies of the asymmetry can be used to verify the point-like approximation used in calculation of radiative corrections due to emission of photons by pions or kaons.

hep-ph↗