J/Psi Production from Electromagnetic Fragmentation in Z decay

Abstract

The rate for $Z^0\to J/\psi +{\ell }^{+}{\ell }^{-}$ is suprisingly large with about one event for every million $Z^0$ decays. The reason for this is that there is a fragmentation contribution that is not suppressed by a factor of $M_{\psi }^2/M_Z^2$. In the fragmentation limit $M_Z\to \infty$ with $E_{\psi }/M_Z$ fixed, the differential decay rate for $Z^0\to J/\psi +{\ell }^{+}{\ell }^{-}$ factors into electromagnetic decay rates and universal fragmentation functions. The fragmentation functions for lepton fragmentation and photon fragmentation into $J/\psi$ are calculated to lowest order in $\alpha$. The fragmentation approximation to the rate is shown to match the full calculation for $E_{\psi }$ greater than about $3M_{\psi }$.

16 pages and 8 figures

References in corpus (6)

• Gluon Fragmentation into Heavy Quarkonium
• Z^0 Decay into Charmonium via Charm Quark Fragmentation
• Perturbative QCD Fragmentation Functions for $B_c$ and $B_c^{\ast }$ Production
• Heavy Quark Fragmentation to Baryons Containing Two Heavy Quarks
• Heavy Quark Fragmentation to Polarised Quarkonium
• Electromagnetic Production of Quarkonium in $Z^0$ decay

Cited by in corpus (13)

• Production of Heavy Quarkonium in High Energy Colliders
• Collider Phenomenology of Unparticle Physics
• Observation and measurements of the production of prompt and non-prompt $J/\psi$ mesons in association with a $Z$ boson in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector
• Prompt Upsilon and Psi Production at LEP
• Exclusive Double-Charmonium Production from e^+ e^- Annihilation into Two Virtual Photons
• J/psi Production at LEP: Revisited and Resummed
• J/ψElectromagnetic Production at e^+e^- colliders
• The J/ψProduction Associated with a Hard Photon and the Color-Octet Singnature in e^+e^- Annihilation
• Observation of the Z $\to \psi {\ell }^{+}{\ell }^{-}$ decay in pp collisions at $\sqrt{s}=$ 13 TeV
• Note on rare $Z$-boson decays to double heavy quarkonia
• Photoproductions of dileptons, photons, and light vector mesons in p-p, p-Pb, and Pb-Pb collisions at Large Hadron Collider energies
• Rare $W$-boson decays into a vector meson and lepton pair
• Observation of the decay $\mathrm{Z}\to \psi {\ell }^{+}{\ell }^{-}\to {\mu }^{+}{\mu }^{-}{\ell }^{+}{\ell }^{-}$ with the CMS detector