Impact of new particles on the ratio of Electromagnetic form factors

Abstract

We consider the electromagnetic form factors ratio in the Rosenbluth and polarization methods. We explore the impact of adding new particles as the mediators in the electron-proton scattering on these ratios. Consequently, we find some bound on the scalar coupling as $\alpha_{sc}\sim 10^{-5}$ for $m_{sc}\sim 5 MeV-2 GeV$ and $\alpha_{sc}\sim 10^{-4}-10^{-3}$ for $m_{sc}\sim 2-10 GeV$. Meanwhile, the vector coupling is bounded as $\alpha_v\sim 10^{-5}$ for $m_v\sim 5 MeV-1.1 GeV$ and $\alpha_v\sim 10^{-4}-10^{-3}$ for $m_v\sim 1.2-10 GeV$. These constraints are in complete agreement with those which is found from other independent experiments.