Electron-to-Tau Lepton Flavor Violation at the Electron-Ion Collider

Abstract

We analyze the potential sensitivity of a search for $e\to \tau$ conversion at a proposed electron-ion collider (EIC) facility. To that end, we calculate the cross sections for $e\to \tau$ events in a leptoquark framework assuming that the leptoquark masses are on the order of several hundred GeV or more. Given present limits on leptoquarks from direct searches at HERA and rare decay processes, an EIC sensitive to 0.1 fb $e\to \tau$ cross sections could probe previously unexplored regions of parameter space for these lepton flavor violating events (assuming 90 GeV center-of-mass energy and 10 fb${}^{-1}$ integrated luminosity). Depending on the species of leptoquark and flavor structure of the couplings, an EIC search could surpass the HERA and rare process sensitivity to $e\to \tau$ conversion amplitudes by as much as an order of magnitude or more. We also derive updated limits on quark flavor-diagonal LFV leptoquark interactions using the most recent BaBar $\tau \to e\gamma$ search. We find that limits from an EIC $e\to \tau$ search could be competitive with the most recent $\tau \to e\gamma$ limit for a subset of the quark flavor-diagonal leptoquark couplings. Using an SU(5) GUT model in which leptoquark couplings are constrained by the neutrino masses and mixing, we illustrate how observable leptoquark-induced $e\to \tau$ conversion can be consistent with stringent LFV limits imposed by $\mu \to e\gamma$ and $\mu \to e$ conversion searches.

19 pages, 7 figures

References in corpus (4)

• Low Energy Precision Test of Supersymmetry
• Search for Lepton Flavor Violating tau Decays into Three Leptons
• Minimal Flavor Violation in the Lepton Sector of the Randall-Sundrum Model
• Leptoquarks and Neutrino Masses at the LHC

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• Searching for new physics at $\mu \to e$ facilities with ${\mu }^{+}$ and ${\pi }^{+}$ decays at rest
• Displaced Signals of Hidden Vectors at the Electron-Ion Collider
• Snowmass 2021 White Paper: Charged lepton flavor violation in the tau sector
• Testing Lepton Flavor Universality at the Electron-Ion Collider
• Probing charged lepton flavor violation with a positron beam at CEBAF (JLAB)
• Probing top-quark electroweak couplings indirectly at the Electron-Ion Collider
• Charged lepton flavor violation associated with heavy quark production in deep inelastic lepton-nucleon scattering via scalar exchange