Lattice QCD estimate of the ${\eta }_c(2S)\to J/\psi \gamma$ decay rate

Damir Becirevic, Michael Kruse, Francesco Sanfilippo

We compute the hadronic matrix element relevant to the physical radiative decay ${\eta }_c(2S)\to J/\psi \gamma$ by means of lattice QCD. We use the (maximally) twisted mass QCD action with Nf=…