Four-lepton decays of neutral vector mesons

We investigate the rare electromagnetic decays of neutral vector mesons (exemplified by $J/\ensuremath{\psi}$, $\mathrm{\ensuremath{\Upsilon}}$, ${\ensuremath{\rho}}^{0}$, $\ensuremath{\omega},\ensuremath{\phi}$, \dots{}) into four charged leptons [$2({e}^{+}{e}^{\ensuremath{-}})$, $2({\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})$, $2({\ensuremath{\tau}}^{+}{\ensuremath{\tau}}^{\ensuremath{-}})$, ${e}^{+}{e}^{\ensuremath{-}}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$, ${e}^{+}{e}^{\ensuremath{-}}{\ensuremath{\tau}}^{+}{\ensuremath{\tau}}^{\ensuremath{-}}$, \dots{}] at lowest order in QED. In contrast to the case of vector meson decay into a single pair of leptons, the lepton mass must be retained in these four-lepton decay channels to cut off the mass singularity. Owing to more pronounced collinear enhancement, the branching fractions of vector mesons decays into $2({e}^{+}{e}^{\ensuremath{-}})$ are considerably greater than those for decays into $2({\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})$. The decay channels $J/\ensuremath{\psi}(\mathrm{\ensuremath{\Upsilon}})\ensuremath{\rightarrow}2({e}^{+}{e}^{\ensuremath{-}}),{e}^{+}{e}^{\ensuremath{-}}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ are predicted to have branching fractions of order ${10}^{\ensuremath{-}5}$, which appear to have bright observation prospect at BESIII, Belle 2, and LHC experiments.

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.