Examinando por Autor "Antonov A."

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    First constraints on the Lμ− Lτ explanation of the muon g-2 anomaly from NA64-e at CERN
    (Springer Science and Business Media Deutschland GmbH, 2024-07) Andreev, Yu. M.; Antonov A.; Banerjee D.; Banto Oberhauser B.; Bernhard J.; Bisio P.; Celentano A.; Charitonidis N.; Cooke D.; Crivelli P.; Depero E.; Dermenev A.V.; Donskov S.V.; Dusaev R.R.; Enik T.; Frolov V.N.; Gardikiotis A.; Gertsenberger S.V.; Girod S.; Gninenko S.N.; Hösgen M.; Kachanov V.A.; Kambar Y.; Karneyeu A.E.; Kasianova E.A.; Kekelidze G.; Ketzer B.; Kirpichnikov D.V.; Kirsanov M.M.; Kolosov V.N.; Kramarenko V.A.; Kravchuk L.V.; Krasnikov N.V.; Kuleshov S.V.; Lyubovitskij V.E.; Lysan V.; Marini A.; Marsicano L.; Matveev V.A.; Mena Fredes R.; Mena Yanssen R.; Molina Bueno L.; Mongillo M.; Peshekhonov D.V.; Polyakov V.A.; Radics B.; Salamatin K.; Samoylenko V.D.; Sieber H.; Shchukin D.; Soto O.; Tikhomirov V.O.; Tlisova I.; Toropin A.N.; Tuzi M.; Ulloa P.; Volkov P.V.; Volkov, V. Yu.; Voronchikhin I.V.; Zamora-Saá J.
    The inclusion of an additional U(1) gauge Lμ − Lτ symmetry would release the tension between the measured and the predicted value of the anomalous muon magnetic moment: this paradigm assumes the existence of a new, light Z′ vector boson, with dominant coupling to μ and τ leptons and interacting with electrons via a loop mechanism. The Lμ − Lτ model can also explain the Dark Matter relic abundance, by assuming that the Z′ boson acts as a “portal” to a new Dark Sector of particles in Nature, not charged under known interactions. In this work we present the results of the Z′ search performed by the NA64-e experiment at CERN SPS, that collected ~ 9 × 1011 100 GeV electrons impinging on an active thick target. Despite the suppressed Z′ production yield with an electron beam, NA64-e provides the first accelerator-based results excluding the g − 2 preferred band of the Z′ parameter space in the 1 keV
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    Probing light dark matter with positron beams at NA64
    (American Physical Society, 2024-02-01) Andreev, Yu. M.; Antonov A.; Banerjee D.; Banto Oberhauser B.; Bernhard J.; Bisio P.; Bondí M.; Celentano A.; Charitonidis N.; Cooke D.; Crivelli P.; Depero E.; Dermenev A.V.; Donskov S.V.; Dusaev R.R.; Enik T.; Frolov V.N.; Gardikiotis A.; Gninenko S.N.; Hösgen M.; Kachanov V.A.; Kambar Y.; Karneyeu A.E.; Kekelidze G.; Ketzer B.; Kirpichnikov D.V.; Kirsanov M.M.; Gertsenberger S.V.; Girod S.; Kasianova E.A.; Kramarenko V.A.; Kravchuk L.V.; Krasnikov N.V.; Kuleshov S.V.; Lyubovitskij V.E.; Lysan V.; Marini A.; Marsicano L.; Matveev V.A.; Mena Fredes R.; Mena Yanssen R.; Molina Bueno L.; Mongillo M.; Peshekhonov D.V.; Polyakov V.A.; Radics B.; Salamatin K.; Samoylenko V.D.; Sieber H.; Shchukin D.; Soto O.; Tikhomirov V.O.; Tlisova I.; Toropin A.N.; Tuzi M.; Ulloa P.; Volkov P.V.; Volkov, V. Yu.; Voronchikhin I.V.
    We present the results of a missing-energy search for light dark matter which has a new interaction with ordinary matter transmitted by a vector boson, called dark photon A′. For the first time, this search is performed with a positron beam by using the significantly enhanced production of A′ in the resonant annihilation of positrons with atomic electrons of the target nuclei, followed by the invisible decay of A′ into dark matter. No events were found in the signal region with (10.1±0.1)×109 positrons on target with 100 GeV energy. This allowed us to set new exclusion limits that, relative to the collected statistics, prove the power of this experimental technique. This measurement is a crucial first step toward a future exploration program with positron beams, whose estimated sensitivity is here presented.