Sea quark contributions to nucleon electromagnetic form factors with the nonlocal chiral effective Lagrangian * * Supported by the National Natural Sciences Foundations of China (11475186), the Sino-German CRC 110 “Symmetries and the Emergence of Structure in QCD” project by NSFC (11621131001)

Ming-Yang Yang,Ping Wang

doi:10.1088/1674-1137/44/5/053101

Abstract

The sea quark contributions to the nucleon electromagnetic form factors of the up, down and strange quarks are studied with the nonlocal chiral effective Lagrangian. Both octet and decuplet intermediate states are included in the one loop calculations. Compared with the strange quark form factors, although their signs are the same, the absolute value of the light quark form factors are much larger. For both the electric and magnetic form factors, the contribution of the d quark is larger than of the u quark. The current lattice simulations of the light sea quark form factors are in between our results for the u and dquarks.

Highlights

Nucleon structure is one of the hottest research objects in hadron physics
In 2002, we studied the strange form factors with perturbative chiral quark model (PCQM) and it was found the strange charge form factor is positive, while the strange magnetic form factor is negative [8]
It can be seen clearly that our calculated sea quark contribution is obviously larger than the lattice data

Summary

Introduction

Nucleon structure is one of the hottest research objects in hadron physics. A lot of experimental and theoretical efforts have been made on this topic. In addition to the valence quark, the information from sea quark contribution to nucleon properties is very important both analytically and numerically It is crucial for the leading non-analytic behavior of the physical quantities. The nucleon form factors as well as the sea contribution from light and strange quark were simulated on lattice even at physical pion mass [21–24]. Lagrangian which makes it possible to study the hadron properties at relatively large Q2 [25–30]. We will apply the nonlocal Lagrangian to investigate the light sea quark contribution to the nucleon form factors. [33], we can get the sea and valence quark contribution separately This method is equivalent to the quenched chiral perturbation theory.

Chiral effective Lagrangian

Electromagnetic form-factors

Numerical Results

Summary