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Deep inelastic e−τ and μ−τ conversion in the NA64 experiment at the CERN SPS

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Physical Review D 2018年第1期98卷 015007-015007页

作者： Sergei Gninenko Sergey Kovalenko Serguei Kuleshov Valery E. Lyubovitskij Alexey S. Zhevlakov Institute for Nuclear Research 117312 Moscow Russia Departamento de Física y Centro Científico Tecnológico de Valparaíso-CCTVal Universidad Técnica Federico Santa María Casilla 110-V Valparaíso Chile Institut für Theoretische Physik Universität Tübingen Kepler Center for Astro and Particle Physics Auf der Morgenstelle 14 D-72076 Tübingen Germany Department of Physics Tomsk State University 634050 Tomsk Russia Tomsk State Pedagogical University 634061 Tomsk Russia Matrosov Institute for System Dynamics and Control Theory SB RAS Lermontov str. 134 664033 Irkutsk Russia

We study the lepton flavor violating (LFV) e(μ)−τ conversion in deep inelastic scattering (DIS) of electrons (muons) on fixed-target nuclei. Our model-independent analysis is based on the set of low-energy effective four-fermion LFV operators composed of leptons and quarks with the corresponding mass scales Λk for each operator. Using the estimated sensitivity of the search for this LFV process in events with large missing energy in the NA64 experiment at the CERN SPS, we derive lower limits for Λk and compared them with the corresponding limits existing in the literature. We show that the DIS e(μ)−τ conversion is able to provide a plenty of new limits as yet nonexisting in the literature. We also analyzed the energy spectrum of the final-state τ and discussed the viability of the observation of this process in the NA64 experiment and ones akin to it. The case of polarized beams and targets is also discussed.

关键词： Particle interactions

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Preface

CEUR Workshop Proceedings 2019年 2406卷

作者： Haungs, Andreas Kryukov, Alexander Bychkov, Igor Shigarov, Alexey Kazarina, Yulia Tokareva, Victoria Karlsruhe Institute of Technology Institute for Nuclear Physics Karlsruhe Germany Lomonosov Moscow State University Skobeltsyn Institute of Nuclear Physics Moscow Russia Matrosov Institute for System Dynamics and Control Theory of Siberian Branch of Russian Academy of Sciences Irkutsk Russia Applied Physics Institute Irkutsk State University Irkutsk Russia

Updated limits on the CP violating ηππ and η0ππ couplings derived from the neutron EDM

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arXiv 2019年

作者： Zhevlakov, Alexey S. Gutsche, Thomas Lyubovitskij, Valery E. Department of Physics Tomsk State University Tomsk634050 Russia Matrosov Institute for System Dynamics and Control Theory SB RAS Lermontov str. 134 Irkutsk664033 Russia Institut für Theoretische Physik Universität Tübingen Kepler Center for Astro and Particle Physics Auf der Morgenstelle 14 TübingenD-72076 Germany Departamento de Física y Centro Científico Tecnológico de Valparaíso-CCTVal Universidad Técnica Federico Santa María Casilla 110-V Valparaíso Chile

We complete our derivation of upper limits on the CP violating ηππ and η0ππ couplings from an analysis of their two-loop contributions to the neutron electric dipole moment (nEDM). We use a phenomenological Lagrangian approach which is formulated in terms of hadronic degrees of freedom - nucleons and pseudoscalar mesons. The essential part of the Lagrangian contains the CP violating couplings between η(η0) and pions. Previously, we included photons using minimal substitution in case of the proton and charged pions. Now we extend our Lagrangian by adding the nonminimal couplings, i.e. anomalous magnetic couplings of nucleons with the photon. The obtained numerical upper limits for the ηππ and η0ππ couplings |fηππ(Mη2)| −11 and |fη0ππ(Mη20)| −11 can be useful for the related, planned experiments at the JLab Eta Factory. Using present experimental limits on the nEDM, we derive upper limits on the CP violating θ¯ parameter of θ¯ −10. Copyright © 2019, The Authors. All rights reserved.

关键词： Lagrange multipliers

Deuteron EDM induced by CP violating couplings of pseudoscalar mesons

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arXiv 2020年

作者： Zhevlakov, Alexey S. Lyubovitskij, Valery E. Department of Physics Tomsk State University Tomsk634050 Russia Matrosov Institute for System Dynamics and Control Theory SB RAS Lermontov str. 134 Irkutsk664033 Russia Institut für Theoretische Physik Universität Tübingen Kepler Center for Astro and Particle Physics Auf der Morgenstelle 14 TübingenD-72076 Germany Departamento de Física y Centro Científico Tecnológico de Valparaíso-CCTVal Universidad Técnica Federico Santa María Casilla 110-V Valparaíso Chile

We analyze contributions to the electric dipole (EDM) and Schiff (SFM) moments of deuteron induced by the CP-violating three-pseudoscalar meson couplings using phenomenological Lagrangian approach involving nucleons and pseudoscalar mesons P = π, K, η, η0. Deuteron is considered as a proton-neutron bound state and its properties are defined by one- and two-body forces. One-body forces correspond to a picture there proton and neutron are quasi free constituents of deuteron and their contribution to the deuteron EDM (dEDM) is simply the sum of proton and neutron EDMs. Two-body forces in deuteron are induced by one-meson exchange between nucleons. They produce a contribution to the dEDM, which is estimated using corresponding potential approach. From numerical analysis of nucleon and deuteron EDMs we derive stringent limits on CP-violating hadronic couplings and θ¯ parameter. We showed that proposed measurements of proton and deuteron EDMs at level of ∼ 10−29 by the Store Ring EDM and JEDI Collaborations will provide more stringent upper limits on the CP violating parameters. Copyright © 2020, The Authors. All rights reserved.

关键词： Deuterium

Constructing numerical solutions to a nonlinear heat conduction equation with boundary conditions degenerating at the initial moment of time

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AIP Conference Proceedings 2016年第1期1785卷

作者： L. F. Spevak A. L. Kazakov 1Institute of Engineering Science UB RAS Ekaterinburg Russia 2Institute for System Dynamics and Control Theory SB RAS Irkutsk Russia

This paper deals with one-dimensional boundary value problems for a non-linear heat conduction equation with a power dependence of the heat conductivity coefficient on temperature. New solution algorithms are constructed for the instances of boundary conditions degenerating at the initial time moment. A comparison of the obtained solutions with known exact solutions shows the effectiveness of the proposed algorithms.

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On a solution to a nonlinear heat transfer model by the BEM

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AIP Conference Proceedings 2023年第1期2624卷

作者： A. L. Kazakov L. F. Spevak Matrosov Institute for System Dynamics and Control Theory Siberian Branch of the Russian Academy of Sciences Irkutsk Russia Irkutsk State Transport University Irkutsk Russia Ural State University of Railway Transport Ekaterinburg Russia Institute of Engineering Science Ural Branch of the Russian Academy of Sciences Ekaterinburg Russia

The paper deals with a nonlinear heat transfer model based on the nonlinear second order degenerate parabolic equation with arbitrary form of nonlinearity. Boundary value problems with two non-stationary boundary conditions are discussed: the problem with a specified heat wave front and the problem with a condition specifying the desired function at some manifold. A new existence theorem is formulated. Time-step algorithms based on the boundary element method and the dual reciprocity method are developed. Iteration procedures converging to the continuous solution on each time step are proposed. The algorithms are verified by comparison with known exact solution.

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Tensor meson contribution to the Lamb shift and hyperfine splitting in muonic hydrogen

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Journal of Physics: Conference Series 2020年第1期1435卷

作者： A E Dorokhov A P Martynenko F A Martynenko A E Radzhabov Joint Institute of Nuclear Research BLTP 141980 Moscow region Dubna Russia Samara National Research University named after acad. S.P. Korolev 443086 Samara Russia Matrosov Institute for System Dynamics and Control Theory SB RAS 664033 Irkutsk Russia

We calculate the tensor meson exchange contribution to the interaction operator of muon and proton, which is determined by the tensor meson coupling with two photon state. For the construction of transition form factor T → γγ we use the monopole parametrization over photon four-momenta and experimental data on the decay width ΓTγγ. It is shown that tensor meson f2(1270) exchange gives essential contribution to the Lamb shift in muonic hydrogen ΔΕLs (2P – 2S) which should be taken into account for a comparison with precise experimental data.

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Implication of the hidden sub-GeV bosons for the (g - 2)μ, 8Be-4He anomaly, proton charge radius, EDM of fermions and dark axion portal

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arXiv 2020年

作者： Kirpichnikov, D.V. Lyubovitskij, Valery E. Zhevlakov, Alexey S. Institute for Nuclear Research Russian Academy of Sciences Moscow117312 Russia Institut für Theoretische Physik Universität Tübingen Kepler Center for Astro and Particle Physics Auf der Morgenstelle 14 TübingenD-72076 Germany Departamento de Física Centro Científico Tecnológico de Valparaíso-CCTVal Universidad Técnica Federico Santa María Casilla 110-V Valparaíso Chile Department of Physics Tomsk State University Tomsk634050 Russia Matrosov Institute for System Dynamics and Control Theory SB RAS Lermontov str. 134 Irkutsk664033 Russia

We discuss new physics phenomenology of hidden scalar (S), pseudoscalar (P), vector (V ) and axial-vector (A) particles coupled to nucleons and leptons, which could give contributions to proton charge radius, (g - 2)μ, 8Be-4He anomaly and electric dipole moment (EDM) of Standard Model (SM) particles. In particular, we estimate sensitivity of NA64μ experiment to observe muon missing energy events involving hidden scalar and vector particles. That analysis is based on GEANT4 Monte Carlo simulation of the signal process of muon scattering off target nuclei μN → μNS(V ) followed by invisible boson decay into Dark Matter (DM) particles, S(V ) → χχ. The existence of light subGeV bosons could possibly explain the muon (g -2) anomaly observed. We also summarize existing bounds on ATOMKI X17(JP= 0-, 1±) boson coupling with neutron, proton and electron. We implement these constraints to estimate the contribution of P, V and A particles to proton charge radius via direct 1-loop calculation of Sachs form factors. The analysis reveals the corresponding contribution is negligible. We also calculate bounds on dark axion portal couplings of dimension-five operators, which contribute to the EDMs of leptons and neutron. Copyright © 2020, The Authors. All rights reserved.

关键词： Bosons

New ideas for handling of loop and angular integrals in D-dimensions in QCD

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arXiv 2021年

作者： Lyubovitskij, Valery E. Wunder, Fabian Zhevlakov, Alexey S. Institut für Theoretische Physik Universität Tübingen Kepler Center for Astro and Particle Physics Auf der Morgenstelle 14 TübingenD-72076 Germany Departamento de Física Centro Científico Tecnológico de Valparaíso-CCTVal Universidad Técnica Federico Santa María Casilla 110-V Valparaíso Chile Department of Physics Tomsk State University Tomsk634050 Russia Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research Dubna141980 Russia Matrosov Institute for System Dynamics and Control Theory SB RAS Lermontov str. 134 Irkutsk664033 Russia

We discuss new ideas for consideration of loop diagrams and angular integrals in D-dimensions in QCD. In case of loop diagrams, we propose the covariant formalism of expansion of tensorial loop integrals into the orthogonal basis of linear combinations of external momenta. It gives a very simple representation for the final results and is more convenient for calculations on computer algebra systems. In case of angular integrals we demonstrate how to simplify the integration of differential cross sections over polar angles. Also we derive the recursion relations, which allow to reduce all occurring angular integrals to a short set of basic scalar integrals. All order Ε-expansion is given for all angular integrals with up to two denominators based on the expansion of the basic integrals and using recursion relations. A geometric picture for partial fractioning is developed which provides a new rotational invariant algorithm to reduce the number of denominators. © 2021, CC BY.

关键词： Expansion