Improved analysis of double $J/\psi$ production in $Z$-boson decay

Abstract

In this paper, we present an improved calculation for the decay rate of the rare $Z$-boson decay into $J/\psi +J/\psi$. This decay is dominated by the photon fragmentation mechanism, i.e., the transition $Z\to J/\psi +{\gamma }^{\ast }$ followed by the fragmentation ${\gamma }^{\ast }\to J/\psi$. In our calculation, the amplitude of ${\gamma }^{\ast }\to J/\psi$ is extracted from the measured value of $\Gamma (J/\psi \to e^{+}{e}^{-})$, and the amplitude of $Z\to J/\psi +{\gamma }^{\ast }$ is calculate through the light-cone approach. The higher-order QCD and relativistic corrections in the amplitude of ${\gamma }^{\ast }\to J/\psi$ and the large logarithms of $m_{{}_Z}^2/m_c^2$ that appear in the amplitude of $Z\to J/\psi +{\gamma }^{\ast }$ are resummed in our calculation. Besides, the non-fragmentation amplitude is calculated based on the NRQCD factorization, and the next-to-leading order QCD and relativistic corrections are included. The obtained branching fraction for this $Z$ decay channel is $8.66_{-0.69}^{+1.48}\times 10^{-11}$.

arXiv comment10 pages, 2 figures

References in corpus (28)

• The Cosmological Parameters 2006
• Big-Bang nucleosynthesis (Particle Data Group mini-review)
• Rigorous QCD Analysis of Inclusive Annihilation and Production of Heavy Quarkonium
• Automatized One-Loop Calculations in 4 and D dimensions
• Generating Feynman Diagrams and Amplitudes with FeynArts 3
• Asymptotic expansion of Feynman integrals near threshold
• New Developments in FeynCalc 9.0
• The renormalization of the axial anomaly in dimensional regularization
• Algorithm FIRE -- Feynman Integral REduction
• Higher Twist Distribution Amplitudes of Vector Mesons in QCD: Formalism and Twist Three Distributions
• The $\rho$ Meson Light-Cone Distribution Amplitudes of Leading Twist Revisited
• Higgs boson decays to quarkonia and the Hccbar coupling
• Light Cone Sum Rules for the pi0-gamma*-gamma Form Factor Revisited
• Improved determination of color-singlet nonrelativistic QCD matrix elements for S-wave charmonium
• $Apart: A Generalized Mathematica Apart Function
• Resummation of Relativistic Corrections to e+ e- -> J/psi+eta_c
• NRQCD Factorization for Twist-2 Light-Cone Wave-Functions of Charmonia
• Three-loop matching of the vector current
• The leading twist light-cone distribution amplitudes for the S-wave and P-wave quarkonia and their applications in single quarkonium exclusive productions
• Factorization in exclusive quarkonium production
• $Z$-boson decays to a vector quarkonium plus a photon
• New approach to the resummation of logarithms in Higgs-boson decays to a vector quarkonium plus a photon
• Exclusive Two-Vector-Meson Production from e^+ e^- Annihilation
• Relativistic corrections to light-cone distribution amplitudes of S-wave $B_c$ mesons and heavy quarkonia
• Double Charmonia Production in Exclusive $Z$ Boson Decays
• $Z$ boson radiative decays to a $S$-wave quarkonium at NNLO and NLL accuracy
• Note on rare $Z$-boson decays to double heavy quarkonia
• Analysis of double-$J/\psi$ production in $Z$ decay at next-to-leading-order QCD accuracy