Empirical transverse charge densities in the nucleon-to-P11(1440) transition

TL;DR

This paper analyzes the electromagnetic transition from the nucleon to the P11(1440) resonance using experimental data to map quark transverse charge densities, revealing spatial quark distributions during the transition.

Contribution

It provides the first empirical mapping of quark transverse charge densities in the nucleon-to-P11(1440) transition based on recent experimental form factors.

Findings

Up quarks dominate the central 0.5 fm region.

Down quarks are prominent in the outer region up to 1 fm.

Transition involves a radial excitation of the nucleon.

Abstract

Using recent experimental data, we analyze the electromagnetic transition from the nucleon to the P11(1440) resonance. From the resulting empirical transition form factors, we map out the quark transverse charge densities which induce the N to P11(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.