CERN Accelerating science

Preprint
Report number	CERN-EP-2022-118
Title	Search for a light muon-philic Z′ with the NA64-e experiment at CERN
Author(s)	Andreev, Yu. M. ; Banerjee, D. ; Banto Oberhauser, B. ; Bernhard, J. ; Bisio, P. ; Bondì, M. ; Burtsev, V. E. ; Celentano, A. ; Charitonidis, N. ; Chumakov, A. G. ; Cooke, D. ; Crivelli, P. ; Depero, E. ; Dermenev, A. V. ; Donskov, S. V. ; Dusaev, R. R ; Enik, T. ; Frolov, V. N. ; Gardikiotis, A. ; Gerassimov, S. G. ; Gninenko, S. N. ; Hösgen, M. ; Jeckel, M. ; Kachanov, V. A. ; Karneyeu, A. E. ; Kekelidze, G. ; Ketzer, B. ; Kirpichnikov, D. V. ; Kirsanov, M. M. ; Kolosov, V. N. ; Konorov, I. V. ; Kovalenko, S. G. ; Kramarenko, V. A. ; Kravchuk, L. V. ; Krasnikov, N. V. ; Kuleshov, S. V. ; Lyubovitskij, V. E. ; Lysan, V. ; Marsicano, L. ; Matveev, V. A. ; Mikhailov, Yu. V. ; Molina Bueno, L. ; Peshekhonov, D. V. ; Polyakov, V. A. ; Radics, B. ; Rojas, R. ; Rubbia, A. ; Samalantin, K. ; Samoylenko, V. D. ; Sieber, H. ; Shchukin, D. ; Tikhomirov, V. O. ; Tlisova, I. ; Toropin, A. N. ; Trifonov, A. Yu ; Ulloa, P. ; Vasilishin, B. I. ; Vasquez Arenas, G. ; Volkov, P. V. ; Volkov, V. Yu. ; Voronchikhin, I.
Publication	2022
Imprint	01 Jun 2022
Subject category	Particle Physics - Experiment
Accelerator/Facility, Experiment	CERN SPS ; NA64
Keywords	electroweak interaction ; calorimeter ; experimental results
Abstract	The extension of Standard Model made by inclusion of additional U (1) gauge L_μ − L_τ symmetry can explain the difference between the measured and the predicted value of the muon magnetic moment and solve the tension in B meson decays. This model predicts the existence of a new, light Z′ vector boson, predominantly coupled to second and third generation leptons, whose interaction with electrons is due to a loop mechanism involving muons and taus. In this work, we present a rigorous evaluation of the upper limits in the Z′ parameter space, obtained from the analysis of the data collected by the NA64-e experiment at CERN SPS, that performed a search for light dark matter with 2.84 × 10^11 electrons impinging with 100 GeV on an active thick target. The resulting limits, despite being included in a region already investigated by neutrino experiments, touch the muon g − 2 preferred band for values of the Z′ mass of order of 1 MeV. The sensitivity projections for the future high-statistics NA64-e runs demonstrate the power of the electrons/positron beam approach in this theoretical scenario.
Copyright/License	Preprint: © 2022-2024 CERN (License: CC-BY-4.0)
Submitted by	andrea.celentano@cern.ch