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Probing lepton flavor violation via $e\tau$ production in an effective framework at a future electron-positron circular collider

by S. M. Etesami, R. Jafari, M. Mohammadi Najafabadi and S. Tizchang

Submission summary

Abstract

In the standard model framework, lepton flavor is conserved in the interactions, however, it can be violated in some beyond the standard model scenarios. In this study, we consider $e^{\pm}\tau^{\mp}$ production through a four-Fermi lepton flavor violation interaction at the future electron-positron circular collider (FCC-ee). To constrain the Wilson coefficients at four center-of-mass energies of $157.5$, $162.5$, $240$ and $365$ GeV that proposed for the FCC-ee, a standard model effective field theory is considered. The main source of backgrounds are taken into account and the study is performed by including realistic effects of the detector. To improve the result, we combine the individual constraints obtained for each center of mass energy. We show that, the combined limits increase the sensitivity to lepton flavor violation couplings by a factor of around three with respect to the individual results and are comparable to the Belle II prospects.