Oleksii Mikulenko
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Research Subjects
Oleksii Mikulenko has a total of 190 co-authors. Here are the top co-authors by number of shared publications:
- Alexey Boyarsky
University of Leiden
8 shared publications - Maksym Ovchynnikov
European Organization for Nuclear Research (CERN)
7 shared publications Alexey Boyarsky
Instituut-Lorentz Leiden University Niels Bohrweg 2 2333 CA Leiden The Netherlands
4 shared publications- Lesya Shchutska
Institute of Physics, High Energy Physics Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
4 shared publications - Inar Timiryasov
University of Copenhagen
3 shared publications - Kyrylo Bondarenko
International School for Advanced Studies SISSA via Bonomea 265 I-34136 Trieste Italy
3 shared publications
Latest Publications
- Open Access
- 1 September 2026
- Published by Springer Nature in The European Physical Journal C
- Vol. 86 (9) , 1030
SND@LHC upgrade for the high-luminosity LHC: physics reach and installation scenarios
The SND@LHC experiment is currently taking data at the Large Hadron Collider (LHC), exploring the unique forward region at pseudorapidities $$7.2<\eta <8.4$$ . Its physics programme covers neutrinos originating from heavy-flavour decays and feebly interacting particles produced in proton–proton collisions. Building upon the successful operation of the present detector, this paper presents the physics reach of the approved SND@LHC upgrade for Run 4 of the LHC, and compares it with an alternative installation scenario. Lowering the detector by approximately 40 cm and shifting it horizontally by about 30 cm, while keeping it off-axis, increases the total neutrino interaction rate by a factor of five. The paper describes the design of the upgraded detector and compares the physics performance in both installation scenarios.- 1 September 2026
- Published by Springer Nature in The European Physical Journal C
- Vol. 86 (9) , 1030
Open AccessSND@LHC upgrade for the high-luminosity LHC: physics reach and installation scenarios
The SND@LHC experiment is currently taking data at the Large Hadron Collider (LHC), exploring the unique forward region at pseudorapidities $$7.2<\eta <8.4$$ . Its physics programme covers neutrinos originating from heavy-flavour decays and feebly interacting particles produced in proton–proton collisions. Building upon the successful operation of the present detector, this paper presents the physics reach of the approved SND@LHC upgrade for Run 4 of the LHC, and compares it with an alternative installation scenario. Lowering the detector by approximately 40 cm and shifting it horizontally by about 30 cm, while keeping it off-axis, increases the total neutrino interaction rate by a factor of five. The paper describes the design of the upgraded detector and compares the physics performance in both installation scenarios. - Open Access
- 4 June 2025
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2025 (6) , 1-33
Quasi-degenerate heavy neutral leptons in the left-right symmetric model
We discuss the phenomenology of a pair of degenerate GeV-scale Heavy Neutral Leptons within the Left-Right Symmetric Model (LRSM) framework, with the third fermion serving as a dark matter candidate. We highlight the potential of the recently approved SHiP experiment to test the existence of a light dark matter species, and signatures of lepton number violation as a possible experimental probe of the model in various experiments. Our findings include concrete predictions for the effective right-handed couplings $$ {\left({V}_e^R\right)}^2 $$ : $$ {\left({V}_{\mu}^R\right)}^2 $$ : $$ {\left({V}_{\tau}^R\right)}^2 $$ = 0.16 : 0.47 : 0.38 (normal neutrino hierarchy), 0.489 : 0.22 : 0.30 (inverted hierarchy) of the degenerate HNL pair, and $$ {\left({V}_e^R\right)}^2 $$ : $$ {\left({V}_{\mu}^R\right)}^2 $$ : $$ {\left({V}_{\tau}^R\right)}^2 $$ = 0.68 : 0.07 : 0.24 (normal), 0.02 : 0.57 : 0.41 for the dark matter candidate.- 4 June 2025
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2025 (6) , 1-33
Open AccessQuasi-degenerate heavy neutral leptons in the left-right symmetric model
We discuss the phenomenology of a pair of degenerate GeV-scale Heavy Neutral Leptons within the Left-Right Symmetric Model (LRSM) framework, with the third fermion serving as a dark matter candidate. We highlight the potential of the recently approved SHiP experiment to test the existence of a light dark matter species, and signatures of lepton number violation as a possible experimental probe of the model in various experiments. Our findings include concrete predictions for the effective right-handed couplings $$ {\left({V}_e^R\right)}^2 $$ : $$ {\left({V}_{\mu}^R\right)}^2 $$ : $$ {\left({V}_{\tau}^R\right)}^2 $$ = 0.16 : 0.47 : 0.38 (normal neutrino hierarchy), 0.489 : 0.22 : 0.30 (inverted hierarchy) of the degenerate HNL pair, and $$ {\left({V}_e^R\right)}^2 $$ : $$ {\left({V}_{\mu}^R\right)}^2 $$ : $$ {\left({V}_{\tau}^R\right)}^2 $$ = 0.68 : 0.07 : 0.24 (normal), 0.02 : 0.57 : 0.41 for the dark matter candidate. - Open Access
- 8 January 2024
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2024 (1) , 1-22
Measuring lepton number violation in heavy neutral lepton decays at the future muon collider
The future muon collider has the potential to discover feebly interacting particles in a wide range of masses above the electroweak scale. It is particularly suitable to search for heavy neutral leptons (HNLs), as their production cross section $$ \sigma \sim {m}_W^{-2} $$ is not suppressed by the new physics scale. We demonstrate that with the capacity to observe up to 105 events in the previously unexplored TeV mass range, the muon collider provides the means to measure the fraction of lepton number violating (LNV) processes with precision at the level of a percent. This capability enables elucidating the nature of HNLs, allowing us to differentiate between Majorana, Dirac, and non-minimal scenarios featuring multiple degenerate HNLs. We link the observed fraction of LNV processes to the parameters of the model with three degenerate HNLs, which could be responsible for generating baryon asymmetry in the Universe. Additionally, we present a simple estimate for the number of signal events, as well as analyze the feasibility of vector boson fusion processes in searches for HNLs.- 8 January 2024
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2024 (1) , 1-22
Open AccessMeasuring lepton number violation in heavy neutral lepton decays at the future muon collider
The future muon collider has the potential to discover feebly interacting particles in a wide range of masses above the electroweak scale. It is particularly suitable to search for heavy neutral leptons (HNLs), as their production cross section $$ \sigma \sim {m}_W^{-2} $$ is not suppressed by the new physics scale. We demonstrate that with the capacity to observe up to 105 events in the previously unexplored TeV mass range, the muon collider provides the means to measure the fraction of lepton number violating (LNV) processes with precision at the level of a percent. This capability enables elucidating the nature of HNLs, allowing us to differentiate between Majorana, Dirac, and non-minimal scenarios featuring multiple degenerate HNLs. We link the observed fraction of LNV processes to the parameters of the model with three degenerate HNLs, which could be responsible for generating baryon asymmetry in the Universe. Additionally, we present a simple estimate for the number of signal events, as well as analyze the feasibility of vector boson fusion processes in searches for HNLs. - Open Access
Measuring lepton number violation in heavy neutral lepton decays at the future muon collider
The future muon collider has the potential to discover feebly interacting particles in a wide range of masses above the electroweak scale. It is particularly suitable to search for heavy neutral leptons (HNLs), as their production cross section $σ\sim m_W^{-2}$ is not suppressed by the new physics scale. We demonstrate that the muon collider, with the capacity to observe up to $10^5$ events in the previously unexplored TeV mass range, provides the means to measure the fraction of lepton number violating (LNV) processes with precision at the level of a percent. This capability enables elucidating the nature of HNLs, allowing us to differentiate between Majorana, Dirac, and non-minimal scenarios featuring multiple degenerate HNLs. We link the observed fraction of LNV processes to the parameters of the model with three degenerate HNLs, which could be responsible for generating baryon asymmetry in the Universe. Additionally, we present a simple estimate for the number of signal events, as well as analyze the feasibility of vector boson fusion processes in searches for HNLs.Open AccessMeasuring lepton number violation in heavy neutral lepton decays at the future muon collider
The future muon collider has the potential to discover feebly interacting particles in a wide range of masses above the electroweak scale. It is particularly suitable to search for heavy neutral leptons (HNLs), as their production cross section $σ\sim m_W^{-2}$ is not suppressed by the new physics scale. We demonstrate that the muon collider, with the capacity to observe up to $10^5$ events in the previously unexplored TeV mass range, provides the means to measure the fraction of lepton number violating (LNV) processes with precision at the level of a percent. This capability enables elucidating the nature of HNLs, allowing us to differentiate between Majorana, Dirac, and non-minimal scenarios featuring multiple degenerate HNLs. We link the observed fraction of LNV processes to the parameters of the model with three degenerate HNLs, which could be responsible for generating baryon asymmetry in the Universe. Additionally, we present a simple estimate for the number of signal events, as well as analyze the feasibility of vector boson fusion processes in searches for HNLs. - Open Access
Unveiling new physics with discoveries at Intensity Frontier
The idea of feebly interacting particles (FIPs) has emerged as an important approach to address challenges beyond the Standard Model. The next generation of Intensity Frontier experiments is set to explore these particles in greater depth. While many experiments may detect FIP signals in unexplored regions of masses and couplings, interpretation of the properties of particles behind these signals is typically neglected. In this paper, we present a novel framework designed to systematically determine the models behind a potential signal. Our approach allows us to assess the scientific reach of experiments beyond the concept of sensitivity to the smallest coupling constant leading to a detectable signal. We clarify the potential impact such signals could have on particle physics models. This paper is complemented by a Python package for the presented framework, available at omikulen/modeltesting.
Open AccessUnveiling new physics with discoveries at Intensity Frontier
The idea of feebly interacting particles (FIPs) has emerged as an important approach to address challenges beyond the Standard Model. The next generation of Intensity Frontier experiments is set to explore these particles in greater depth. While many experiments may detect FIP signals in unexplored regions of masses and couplings, interpretation of the properties of particles behind these signals is typically neglected. In this paper, we present a novel framework designed to systematically determine the models behind a potential signal. Our approach allows us to assess the scientific reach of experiments beyond the concept of sensitivity to the smallest coupling constant leading to a detectable signal. We clarify the potential impact such signals could have on particle physics models. This paper is complemented by a Python package for the presented framework, available at omikulen/modeltesting.
- Open Access
New physics at the Intensity Frontier: how much can we learn and how?
Intensity Frontier experiments are often evaluated by the smallest coupling it can probe, irrespective of what particle can be found or the scientific significance of its detection. In this work, we propose a new framework that determines the number of events required to characterize new particle properties. For example, we show that Heavy Neutral Leptons require 100 events to establish the neutrino mass hierarchy, and 1000 events to reveal the Majorana phase of active neutrinos. Ultimately, this framework presents a more objective way to connect experiments to their scientific outcomes.
Open AccessNew physics at the Intensity Frontier: how much can we learn and how?
Intensity Frontier experiments are often evaluated by the smallest coupling it can probe, irrespective of what particle can be found or the scientific significance of its detection. In this work, we propose a new framework that determines the number of events required to characterize new particle properties. For example, we show that Heavy Neutral Leptons require 100 events to establish the neutrino mass hierarchy, and 1000 events to reveal the Majorana phase of active neutrinos. Ultimately, this framework presents a more objective way to connect experiments to their scientific outcomes.
- Open Access
- 30 October 2023
- Published by American Physical Society (APS) in Physical Review D
- Vol. 108 (7) , 075028
Sensitivities to feebly interacting particles: Public and unified calculations
The idea that new physics could take the form of feebly interacting particles (FIPs)—particles with a mass below the electroweak scale, but which may have evaded detection due to their tiny couplings or very long lifetime—has gained a lot of traction in the last decade, and numerous experiments have been proposed to search for such particles. It is important, and now very timely, to consistently compare the potential of these experiments for exploring the parameter space of various well-motivated FIPs. The present paper addresses this pressing issue by presenting an open-source tool to estimate the sensitivity of many experiments—located at Fermilab or the CERN’s SPS, LHC, and FCC-hh—to various models of FIPs in a unified way: the Mathematica-based code senscalc.
- 30 October 2023
- Published by American Physical Society (APS) in Physical Review D
- Vol. 108 (7) , 075028
Open AccessSensitivities to feebly interacting particles: Public and unified calculations
The idea that new physics could take the form of feebly interacting particles (FIPs)—particles with a mass below the electroweak scale, but which may have evaded detection due to their tiny couplings or very long lifetime—has gained a lot of traction in the last decade, and numerous experiments have been proposed to search for such particles. It is important, and now very timely, to consistently compare the potential of these experiments for exploring the parameter space of various well-motivated FIPs. The present paper addresses this pressing issue by presenting an open-source tool to estimate the sensitivity of many experiments—located at Fermilab or the CERN’s SPS, LHC, and FCC-hh—to various models of FIPs in a unified way: the Mathematica-based code senscalc.
- Open Access
Can we use heavy nuclei to detect relic neutrinos?
Recent analysis of the viability of solid state-based relic neutrino detectors has revealed the fundamental necessity for the use of heavy, $A>100$, $\beta$-decayers as neutrino targets. Of all heavy isotopes, $^{171}$Tm and $^{151}$Sm stand out for their sufficiently low decay energies, reasonable half-life times and stable daughter nuclei. However, the crucial bit of information, that is the soft neutrino capture cross-section is missing for both isotopes. The main reason for that is a particular type of $\beta$-decay, which precludes a simple link between the isotope's half-life time and the neutrino capture rate. Here we propose an experimental method to bypass this difficulty and obtain the capture cross-section of a soft neutrino by a given isotope from the isotope's $\beta$-spectrum.Open AccessCan we use heavy nuclei to detect relic neutrinos?
Recent analysis of the viability of solid state-based relic neutrino detectors has revealed the fundamental necessity for the use of heavy, $A>100$, $\beta$-decayers as neutrino targets. Of all heavy isotopes, $^{171}$Tm and $^{151}$Sm stand out for their sufficiently low decay energies, reasonable half-life times and stable daughter nuclei. However, the crucial bit of information, that is the soft neutrino capture cross-section is missing for both isotopes. The main reason for that is a particular type of $\beta$-decay, which precludes a simple link between the isotope's half-life time and the neutrino capture rate. Here we propose an experimental method to bypass this difficulty and obtain the capture cross-section of a soft neutrino by a given isotope from the isotope's $\beta$-spectrum. - Open Access
- 20 September 2023
- Published by Springer Nature in The European Physical Journal A
- Vol. 59 (9) , 1-7
Can we use heavy nuclei to detect relic neutrinos?
Recent analysis of the viability of solid state-based relic neutrino detectors has revealed the fundamental necessity for the use of heavy, $$A>100$$ , $$\beta $$ -decayers as neutrino targets. Of all heavy isotopes, "Equation missing" and "Equation missing" stand out for their sufficiently low decay energies, reasonable half-life times and stable daughter nuclei. However, the crucial bit of information, that is the soft neutrino capture cross-section is missing for both isotopes. The main reason for that is a particular type of $$\beta $$ -decay, which precludes a simple link between the isotope’s half-life time and the neutrino capture rate. In light of the necessity for a reliable estimate of the capture rate – unimpeded by potentially devastating theoretical uncertainties – prior to using the isotope in a full-scale experiment, we propose an experimental method to bypass this difficulty and obtain the capture cross-section of a soft neutrino by a given isotope from the isotope’s $$\beta $$ -spectrum.- 20 September 2023
- Published by Springer Nature in The European Physical Journal A
- Vol. 59 (9) , 1-7
Open AccessCan we use heavy nuclei to detect relic neutrinos?
Recent analysis of the viability of solid state-based relic neutrino detectors has revealed the fundamental necessity for the use of heavy, $$A>100$$ , $$\beta $$ -decayers as neutrino targets. Of all heavy isotopes, "Equation missing" and "Equation missing" stand out for their sufficiently low decay energies, reasonable half-life times and stable daughter nuclei. However, the crucial bit of information, that is the soft neutrino capture cross-section is missing for both isotopes. The main reason for that is a particular type of $$\beta $$ -decay, which precludes a simple link between the isotope’s half-life time and the neutrino capture rate. In light of the necessity for a reliable estimate of the capture rate – unimpeded by potentially devastating theoretical uncertainties – prior to using the isotope in a full-scale experiment, we propose an experimental method to bypass this difficulty and obtain the capture cross-section of a soft neutrino by a given isotope from the isotope’s $$\beta $$ -spectrum. - Open Access
- 11 January 2023
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2023 (1) , 1-18
Exploring the potential of FCC-hh to search for particles from B mesons
The Future Circular hadron Collider (FCC-hh) is a proposed successor of the Large Hadron Collider (LHC). FCC-hh would push both the energy and intensity frontiers of searches for new physics particles. In particular, due to higher energy and luminosity than at the LHC, at FCC-hh there would be produced around ≃ 30 times larger amount of B mesons and ≃ 120 times of W bosons, which then may decay into feebly interacting particles. In this paper we demonstrate the potential of FCC-hh by studying its sensitivity to heavy neutral leptons (HNLs) with masses mN< mB. We consider various locations of a displaced decay volume embedded in the planned infrastructure of FCC-hh. We demonstrate that FCC-hh may substantially improve the reach of the parameter space of HNLs as compared to the searches proposed at the LHC.
- 11 January 2023
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2023 (1) , 1-18
Open AccessExploring the potential of FCC-hh to search for particles from B mesons
The Future Circular hadron Collider (FCC-hh) is a proposed successor of the Large Hadron Collider (LHC). FCC-hh would push both the energy and intensity frontiers of searches for new physics particles. In particular, due to higher energy and luminosity than at the LHC, at FCC-hh there would be produced around ≃ 30 times larger amount of B mesons and ≃ 120 times of W bosons, which then may decay into feebly interacting particles. In this paper we demonstrate the potential of FCC-hh by studying its sensitivity to heavy neutral leptons (HNLs) with masses mN< mB. We consider various locations of a displaced decay volume embedded in the planned infrastructure of FCC-hh. We demonstrate that FCC-hh may substantially improve the reach of the parameter space of HNLs as compared to the searches proposed at the LHC.