Sea-quark effects in the pion charge form factor

TL;DR

This paper explores how sea-quark components significantly influence the pion charge form factor, showing that including explicit $(qar q)^2$ states in models aligns well with experimental data at high momentum transfers.

Contribution

It introduces a constituent quark model extended with explicit $(qar q)^2$ components to better explain the pion charge form factor data.

Findings

$(qar q)^2$ components can dominate the form factor at high $Q^2$

Admixtures of up to 50% $(qar q)^2$ fit experimental data

The form factor's sensitivity to quark or antiquark P-states is minimal

Abstract

It is shown that the data on the pion charge form factor admit the possibility for a substantial sea-quark components in the pion wave function. If the charge form factor is calculated with instant form kinematics in a constituent quark model that is extended to include explicit $(q\bar q)^2$ components in the pion wave function, that component will give the dominant contribution to the calculated $\pi^+$ charge form factor at large values of momentum transfer. The present experimental values $Q^2$ can be described well with $(q\bar q)^2$ component admixtures of up to 50%. The sensitivity of the calculated $\pi^+$ charge form factor to whether one of the quarks or one of the antiquarks is taken to be in the P-state is small.