Gravitational form factors of charmonia

We investigate the gravitational form factors of charmonium. Our method is based on a Hamiltonian formalism on the light front known as basis light -front quantization. The charmonium mass spectrum and light -front wave functions were obtained from diagonalizing an effective Hamiltonian that incorporates confinement from holographic QCD and one -gluon exchange interaction from light -front QCD. We proposed a quantum many -body approach to construct the hadronic matrix elements of the energy momentum tensor T ++ and T + - , which are used to extract the gravitational form factors A ( Q 2 ) and D ( Q 2 ) . The obtained form factors satisfy the known constraints, e.g., the von Laue condition. From these quantities, we also extract the energy, pressure and light -front energy distributions of the system. We find that hadrons are multilayer systems.