Production of leptonium in heavy quarkonium decays

Abstract

Lepton pairs with opposite charges can form bound states known as ``leptonium'' through quantum electrodynamic interactions. Heavy quarkonia such as $J/\psi$ are abundantly produced at facilities like BESIII and the future Super Tau-Charm Facility (STCF). In this work, we investigate leptonium production in heavy quarkonium decays, specifically focusing on the processes $\mathcal{Q}⟶(l_1^{+}{l}_2^{-})[n]+\gamma$ ($l_{1,2}=\tau ,\mu ,e$) and $\mathcal{Q}⟶(l_1^{+}{l}_2^{-})[n]+l_1^{-}{l}_2^{+}$. Here, $\mathcal{Q}$ denotes the heavy quarkonium $J/\psi$ or ${\rm Y}$, while $n=$ ${}^1{S}_0$ or ${}^3{S}_1$ corresponds to para-leptonium and ortho-leptonium, respectively. With an annual production of $3.4\times 10^{12}$ $J/\psi$ events at STCF, there is significant potential to observe positronium $(e^{+}{e}^{-})$, muonium $({\mu }^{+}{e}^{-})$, and dimuonium $({\mu }^{+}{\mu }^{-})$. In particular, the ortho-dimuonium $({\mu }^{+}{\mu }^{-}){[}^3{S}_1]$ may be discovered at the future STCF, with an inclusive branching fraction of $Br(J/\psi ⟶({\mu }^{+}{\mu }^{-}){[}^3{S}_1]+X)=1.5\times 10^{-12}$.

32 pages, 13 figures, to be published in PRD

References in corpus (9)

• STCF Conceptual Design Report: Volume 1 -- Physics & Detector
• Production of the Smallest QED Atom: True Muonium (mu^+ mu^-)
• Number of $J/\psi$ events at BESIII
• Prospects for ditauonium discovery at colliders
• Rare and exclusive few-body decays of the Higgs, Z, W bosons, and the top quark
• Ditauonium spectroscopy
• Photoproduction of relativistic QED bound states in hadronic collisions
• True muonium resonant production at $e^{+}{e}^{-}$ colliders with standard crossing angle
• Production of dileptonic bound states in the Higgs boson decay