Lattice study of $J/\Psi$J/Ψ form factors with twisted boundary conditions

Radiative transitions in charmonium from lattice QCD

“…Taking a spread over them yields E 2 (0) = −0.172 (15). This is comparable with previous lattice determinations which found E 2 (0) = −0.109(56) [9] and −0.23(2) [5]. Despite the challenges involved, it can be seen that the methods developed in this work can be used to robustly and precisely determine multiple form factors.…”

“…Lattice QCD, where the theory is discretised on a lattice in a finite spacetime volume and quantities are computed numerically, is a method that allows for systematically-improvable computations within QCD. Lattice calculations of a few radiative transition amplitudes involving low-lying charmonia, such as J/ψ → η c γ, ψ(2S) → η c γ, χ c0 → J/ψ γ, are now mature [5][6][7][8][9][10][11], but there have been fewer calculations involving higher-lying and excited charmonia [12][13][14].…”

Radiative Transitions in Charmonium from Lattice QCD

“…Lattice QCD, where the theory is discretised on a lattice in a finite spacetime volume and quantities are computed numerically, is a method that allows for systematically-improvable computations within QCD. Lattice calculations of a few radiative transition amplitudes involving low-lying charmonia, such as J/ψ → η c γ, ψ(2S) → η c γ, χ c0 → J/ψ γ, are now mature [5][6][7][8][9][10][11], but there have been fewer calculations involving higher-lying and excited charmonia [12][13][14].…”