arXiv subjects

Volodymyr Gorkavenko

Publications and source records attributed to Volodymyr Gorkavenko.

8 recordsLinked to original sources

arXiv2026

Effective interaction of Chern-Simons boson with fermions

We consider a vector extension of the Standard Model (SM) with a Chern-Simons-type interaction. This extension introduces a new massive vector boson (the Chern-Simons (CS) boson) that does not couple directly to SM fermions at tree level. We analyze the effective loop-induced interaction of this new vector boson with SM fermions and study its renormalizability in the $R_ξ$ gauge. We find that, in the effective interaction between the CS boson and same-flavor fermions, the divergent contributions from individual loop diagrams do not cancel when all relevant diagrams are taken into account. In contrast, for interactions involving fermions of different flavors, the corresponding loop-induced contributions are finite and well-defined. This indicates that, in the low-energy limit, the theory exhibits nonrenormalizable behavior in the sector describing the loop-induced interaction of the CS boson with same-flavor fermions. The interaction terms between the CS boson and same-flavor fermions, characterized by divergent coefficients, are identified and must be treated within the framework of effective field theory. Finally, we derive the leading-order effective Lagrangian describing the interaction of a GeV-scale CS boson with SM fermions and discuss the number of independent parameters entering this Lagrangian. The leading-order interaction we obtained turns out to be similar to the interaction of a $Z^\prime$ boson with SM fermions.

hep-th↗

arXiv2026

Effects of Curvature-Scalar Coupling on Vacuum Energy in Flat (3+1)-Dimensional Space-Time

We investigated how a magnetic topological defect affects the vacuum polarization of a charged massive scalar field in a flat $(3+1)$-dimensional space-time. The defect was modeled as an impenetrable to matter field finite-thickness tube with magnetic flux inside. We implemented the most general form of the Robin boundary condition on the surface of the magnetic tube, which enables a fully general analysis of the problem. We have found that in flat spacetime, the total vacuum energy generated by a magnetic topological defect depends on the curvature $ξ$, except for special cases corresponding to the Dirichlet and Neumann boundary conditions. By contrast, when Robin's general boundary conditions are imposed, the induced vacuum energy acquires an explicit dependence on the curvature coupling $ξ$, which is significant even in flat space-time. A detailed study of the dependence of the effect on the boundary condition parameter has been carried out. The obtained results highlight the nontrivial role played by boundary conditions in vacuum polarization phenomena.

hep-th↗

arXiv2025

Divergences in the effective loop interaction of the Chern-Simons bosons with leptons. The unitary gauge case

In this paper, we consider the extension of the Standard Model with Chern-Simons type interaction. There is a new vector massive boson (Chern-Simons bosons) in this extension. Using only three-particle dimension-4 interaction of the Chern-Simons bosons with vector bosons of the SM, we consider effective loop interaction of a new vector boson with leptons. We consider the renormalizability of this loop interaction and conclude that for the case of computation of loop diagrams in the unitary gauge, we can not get rid of the divergences in the effective interaction of the Chern-Simons bosons with leptons.

hep-ph↗

arXiv2025

Constraints on the neutrino extension of the Standard Model and baryon asymmetry of the Universe

Heavy neutral leptons (HNLs) can cause new effective interactions of Standard Model particles, particularly charged lepton flavour violation (cLFV) processes. The non-observation of cLFV processes, therefore, puts constraints on the parameters of the HNLs. We find the relations between the cLFV effective operators in the realistic case when active neutrino masses are non-zero and masses of the HNLs are non-degenerate. This allows us to strengthen the existing cLFV constraints. We also link the baryon asymmetry of the Universe to the same cLFV effective operators, which imposes new restrictions on their values.

hep-ph↗

arXiv2025

Constraints on the parameters of the neutrino extension of the Standard Model

Heavy neutral leptons (HNLs) are hypothetical particles proposed as a potential explanation for neutrino oscillations and the generation of the baryon asymmetry in the Universe. This paper focuses on HNLs with masses significantly above the electroweak scale. It is challenging to test for the presence of such particles directly. However, they leave behind effective interactions of Standard Model particles, leading in particular to charged lepton flavor violation (cLFV) processes. Non-observation of cLFV processes puts therefore constraints on the parameters of the HNLs. In this paper, we find the relations between the effective operators in the realistic case when neutrino masses are non-zero and the HNLs are non-degenerate. This allows us to strengthen the existing cLFV constraints on the tau-flavors from much stronger constraints on muon and electron flavors. We also link the baryon asymmetry of the Universe to the same higher-dimensional effective operators, providing complementary bounds on these parameters.

hep-ph↗

arXiv2024

LHCb potential to discover long-lived new physics particles with lifetimes above 100 ps

For years, it has been believed that the main LHC detectors can only restrictively play the role of a lifetime frontier experiment exploring the parameter space of long-lived particles (LLPs) - hypothetical particles with tiny couplings to the Standard Model. This paper demonstrates that the LHCb experiment may become a powerful lifetime frontier experiment if it uses the new Downstream algorithm reconstructing tracks that do not let hits in the LHCb vertex tracker. In particular, for many LLP scenarios, LHCb may be as sensitive as the proposed experiments beyond main LHC detectors for various LLP models, including heavy neutral leptons, dark scalars, dark photons, and axion-like particles.

hep-ph↗

arXiv2024

Production of Chern-Simons bosons in decays of mesons

We consider the effective interaction of quarks with a new GeV-scale vector particle that couples to electroweak gauge bosons by the so-called effective Chern-Simons interaction. We call this particle the Chern-Simons (CS) boson. We construct an effective Lagrangian of the CS boson interaction with quarks of two different flavors. This interaction is given by a divergent loop diagram, however, it turns out that the divergent part is equal to zero as a consequence of the CKM matrix unitarity in the SM. Therefore, we are able to predict the effective interaction of the CS boson with quarks of different flavors without introducing new unknown parameters to the model, using only parameters of the initial effective Lagrangian. Our result shows that the effective interaction of the CS boson with down-type quarks is sufficiently stronger compared with up-type quarks. Based on our results, we give a prediction for the production of CS bosons in mesons decays. Branching fractions were obtained for the main reactions of the CS production in meson decays. The results obtained will be useful for searching for the long-lived GeV-scale CS boson in intensity frontier experiments.

hep-ph↗

arXiv2021

Phenomenology of GeV-scale scalar portal

We review and revise the phenomenology of the scalar portal -- a new scalar particle with the mass in GeV range that mixes with the Higgs boson. In particular, we consider production channels $B\to S K_1(1270)$ and $B\to S K_0^*(700)$ and show that their contribution is significant. We extend the previous analysis by comparing the production of scalars from decays of mesons, of the Higgs bosons and direct production via proton bremsstrahlung, deep inelastic scattering and coherent scattering on nuclei. Relative efficiency of the production channels depends on the energy of the beam and we consider the energies of DUNE, SHiP and LHC-based experiments. We present our results in the form directly suitable for calculations of experimental sensitivities.

hep-ph↗