Lepton-Flavor-Violating ALPs at the Electron-Ion Collider: A Golden Opportunity

Abstract

Axion-like particles (ALPs) arise in a variety of theoretical contexts and can, in general, mediate flavor violating interactions and parity non-conservation. We consider lepton flavor violating ALPs with GeV scale or larger masses which may, for example, arise in composite dark sector models. We show that a future Electron-Ion Collider (EIC) can uncover or constrain such ALPs via processes of the type $e{A}_Z\to \tau A_{Z}a$, where $A_Z$ is a nucleus of charge $Z$ and $a$ is an ALP in the range $m_{\tau }\le m_a\lesssim 20$ GeV. The production of the ALP can have a large $Z^2$ enhancement from low $Q^2$ electromagnetic scattering of the electron from a heavy ion. Using the gold nucleus ($Z=79$) as an example, we show that the EIC can explore $e-\tau$ flavor violation, mediated by GeV-scale ALPs, well beyond current limits. Importantly, the EIC reach for this interaction is not sensitive to the lepton-flavor conserving ALP couplings, whose possible smallness can render searches using $\tau$ decays ineffective. We also discuss how the EIC electron beam polarization can provide a powerful tool for investigating parity violating ALPs.

17 pages, 4 figures. v2: corrected EIC ion-mode luminosity projection; significant updates to analysis. v3: updated to published version

References in corpus (12)

• New Fixed-Target Experiments to Search for Dark Gauge Forces
• Collider Probes of Axion-Like Particles
• Flaxion: a minimal extension to solve puzzles in the standard model
• Flavor probes of axion-like particles
• Charged Lepton Flavor Violation at the EIC
• The Validity of the Weizsacker-Williams Approximation and the Analysis of Beam Dump Experiments: Production of a New Scalar Boson
• Electron-to-Tau Lepton Flavor Violation at the Electron-Ion Collider
• Unified Scenario for Composite Right-Handed Neutrinos and Dark Matter
• Leptoflavorgenesis: baryon asymmetry of the Universe from lepton flavor violation
• Searching for Flavor-Violating ALPs in Higgs Decays
• Cross sections and energy loss for lepton pair production in muon transport
• Probing charged lepton flavor violation with a positron beam at CEBAF (JLAB)

Cited by in corpus (10)

• The Present and Future of QCD
• gamma-UPC: Automated generation of exclusive photon-photon processes in ultraperipheral proton and nuclear collisions with varying form factors
• Opportunities for new physics searches with heavy ions at colliders
• Heavy Neutral Leptons at the Electron-Ion Collider
• Lepton-Flavor-Violating ALP Signals with TeV-Scale Muon Beams
• Displaced Signals of Hidden Vectors at the Electron-Ion Collider
• Flavor-Violating ALPs, Electron g-2, and the Electron-Ion Collider
• Testing Lepton Flavor Universality at the Electron-Ion Collider
• Probing top-quark electroweak couplings indirectly at the Electron-Ion Collider
• Neutron stars can shine a light on elusive lepton-flavor-violating dark matter