Examinando por Autor "Kuleshov, Sergey"

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    Probing invisible vector meson decay mode with the hadronic beam in the NA64 experiment at SPS CERN
    (American Physical Society, 2023-12) Zhevlakov, Alexey S.; Kirpichnikov, Dmitry V.; Gninenko, Sergei N.; Kuleshov, Sergey; Lyubovitskij, Valery E.
    We test a novel idea of using a π- beam in the fixed-target experiments to search for new physics in the events with missing energy. Bounds for invisible vector ρ meson decay were derived, analyzed, and compared with the current limits on searching dark matter in the accelerator based experiments. We demonstrate that the new approach can be effective tool to probe sub-GeV dark matter parameter space.
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    Test of the vector portal with dark fermions in the charge-exchange reactions in the NA64 experiment at CERN SPS
    (American Physical Society, 2024-04-01) Gninenko, Sergei N.; Kirpichnikov, Dmitry V.; Kuleshov, Sergey; Lyubovitskij, Valery E.; Zhevlakov, Alexey S.
    We consider an experiment to search for dark sector particles in invisible (or semi-invisible) decays of neutral mesons M0=π0, η, η′, ω, f2(1270), which produced the charge-exchange reactions π-+(A,Z)→M0+(A,Z-1);M0→ invisible of high-energy pions (or kaons) on a nuclei target in the NA64 experiment at the CERN SPS. This reaction chain would lead to a striking signature of the signal event - the complete disappearance of the beam energy in the setup [Phys. Rev. D 91, 015004 (2015)PRVDAQ1550-799810.1103/PhysRevD.91.015004]. Using data obtained from the measurements at IHEP (Protvino) and Fermilab (Batavia) we show that the integral cross sections σ for the production of the M0 s slightly deviate from the phenomenological formula σ∼Z2/3, where Z is the nuclei charge. In particular, we present the formulas for the differential and integral cross sections that explicitly depend on the Mandelstam and Z variables. Derived formulas are used to predict the M0 yield as a function of beam energy for several target nuclei, and to estimate the projection sensitivity for the proposed search in the dark vector portal model. Sensitivity to different decay modes of M0s is explored.