Abstract

We propose a Standard Model extension by a U(1)R gauge symmetry where only right-handed chiral fermions can carry a nontrivial charge. Here, we show that the simplest anomaly-free solution to accommodate the proton charge radius discrepancy takes right-handed muons, µR, and first generation quarks, uR and dR. Consistency with the latest muon's (g-2) measurements is achieved through an extra light scalar, which itself must lie in the tens of MeV mass range to be viable.