Decay of the gauge boson with lepton flavor violation

D. Espinosa-Gómez; F. Ramírez-Zavaleta; E. S. Tututi

doi:10.1140/epjc/s10052-023-12069-7

2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2023) 83: 909
https://doi.org/10.1140/epjc/s10052-023-12069-7

Regular Article - Theoretical Physics

Decay of the $Z^{'}$ $Z^\prime$ gauge boson with lepton flavor violation

D. Espinosa-Gómez¹^,2, F. Ramírez-Zavaleta¹ and E. S. Tututi¹^c

¹ Facultad de Ciencias Físico Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Av. Francisco J. Mújica S/N, 58060, Morelia, Michoacán, Mexico
² Ingeniería en Tecnologías de la Información y Comunicaciones, Instituto Tecnológico Superior de Puruándiro, Carretera Puruándiro-Galeana km 4.3, 58532, Puruándiro, Michoacán, Mexico

^c eduardo.tututi@umich.mx

Received: 29 June 2023
Accepted: 24 September 2023
Published online: 10 October 2023

Abstract

The flavor-violating decay of a new neutral massive gauge boson $Z^{'} \to μ e$ $Z^\prime \rightarrow \mu e$ is analyzed in the context of extended models, in which this particle emerges. By means of the analysis of the $μ \to e γ$ $\mu \rightarrow e\gamma$ decay, $μ - e$ $\mu -e$ conversion process in nuclei and the $μ \to e e^{+} e^{-}$ $\mu \rightarrow e e^{+}e^{-}$ decay, the strength of the $Z^{'} μ e$ $Z^\prime \mu e$ coupling is estimated and used to calculate the branching ratio of the $Z^{'} \to μ e$ $Z^\prime \rightarrow \mu e$ decay. This is done for the so-called $Z_{S}, Z_{LR}, Z_{χ}, Z_{ψ}$ $Z_S,\,Z_{LR},\,Z_\chi , Z_\psi$ and $Z_{η}$ $Z_\eta$ bosons. We found that, through the $μ - e$ $\mu -e$ conversion process, the most restrictive bound for the coupling is provided by the $Z_{LR}$ $Z_{LR}$ boson. Meanwhile, by means of the $μ \to e e^{+} e^{-}$ $\mu \rightarrow e e^{+}e^{-}$ decay, the most restrictive bound for the $Z^{'} μ e$ $Z^\prime \mu e$ coupling is provided by the $Z_{χ}$ $Z_\chi$ boson. However, if we concentrate on the less restrictive prediction for the Br( $Z^{'} \to μ e$ $Z^\prime \rightarrow \mu e$ ), this comes from the $Z_{η}$ $Z_\eta$ boson and the resulting branching ratio is less than $10^{- 4}$ $10^{-4}$ . On the other hand, if we consider the most restrictive bound, the branching ratio for the process is below $2 \times 10^{- 7}$ $2\times 10^{-7}$ , which results from the $Z_{RL}$ $Z_{RL}$ boson, and is obtained through the $μ - e$ $\mu -e$ conversion process.

D. Espinosa-Gómez, F. Ramírez-Zavaleta and E. S. Tututi contributed equally to this work.

© The Author(s) 2023

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