Empirical transverse charge densities in the nucleon-to-P_(11)(1440) transition

摘要

Using recent experimental data, we analyze the electromagnetic transition from the nucleon to the P_(11)(1440) resonance. From the resulting empirical transition form factors, we map out the quark transverse charge densities which induce the N→P_(11)(1440) transition. It is found that the transition from the proton to its first radially excited state is dominated by up quarks in a central region of around 0.5 fm and by down quarks in an outer band which extends up to about 1 fm.