The fourth dimension of the nucleon structure: spacetime analysis of the timelike electromagnetic proton form factors

TL;DR

This paper explores the spacetime structure of proton electromagnetic form factors, proposing a time-dependent interpretation of the timelike form factor as a Fourier transform of a temporal function, extending the understanding of nucleon structure.

Contribution

It introduces a novel spacetime analysis of proton form factors, linking spatial and temporal distributions through a unified correlation function.

Findings

Timelike form factor interpreted as Fourier transform of a time-dependent function

Unified correlation function depends on both space and time

Provides a deeper understanding of nucleon structure in spacetime

Abstract

As well known, spacelike proton form factors expressed in the Breit frame may be interpreted as the Fourier transform of static space distributions of electric charge and current. In particular, the electric form factor is simply the Fourier transform of the charge distribution $F(q)=\int e^{i\vec q \cdot \vec r} \rho(r)d^3r$. We don't have an intuitive interpretation of the same level of simplicity for the proton timelike form factor appearing in the reactions $e^+e^-\leftrightarrow \bar{p}p$. However, one may suggest that in the center of mass (CM) frame, where $q_\mu x^\mu =qt$, a timelike electric form factor is the Fourier transform $F(q) =\int e^{iqt} R(t)dt$ of a function $R(t)$ expressing how the electric properties of the forming (or annihilating) proton-antiproton pair evolve in time. Here we analyze in depth this idea, show that the functions $\rho(r)$ and $R(t)$ can be formally written as the time and space integrals of a unique correlation function depending on both time and space coordinates.