Spatial imaging of proton via leading-twist nonskewed GPDs with basis light-front quantization
Satvir Kaur, Siqi Xu, Chandan Mondal, Xingbo Zhao, James P. Vary
Abstract
The internal image of the proton is unveiled by examining the generalized parton distributions (GPDs) at zero skewness, within the basis light-front quantized environment. Several distributions emerge when a quark is sampled with different currents depending upon the helicity arrangements of the active quark and the proton target. We investigate six of the eight leading-twist proton GPDs of the valence quarks, the helicity conserving distributions <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mo stretchy="false">(</a:mo><a:mi>H</a:mi><a:mo>,</a:mo><a:mi>E</a:mi><a:mo>,</a:mo><a:mover accent="true"><a:mrow><a:mi>H</a:mi></a:mrow><a:mrow><a:mo stretchy="false">˜</a:mo></a:mrow></a:mover><a:mo stretchy="false">)</a:mo></a:mrow></a:math> and the helicity nonconserving <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mo stretchy="false">(</g:mo><g:msub><g:mi>H</g:mi><g:mi>T</g:mi></g:msub><g:mo>,</g:mo><g:msub><g:mi>E</g:mi><g:mi>T</g:mi></g:msub><g:mo>,</g:mo><g:msub><g:mover accent="true"><g:mi>H</g:mi><g:mo stretchy="false">˜</g:mo></g:mover><g:mi>T</g:mi></g:msub><g:mo stretchy="false">)</g:mo></g:math> distributions at skewness set to zero (<m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"><m:mi>ζ</m:mi><m:mo>=</m:mo><m:mn>0</m:mn></m:math>). We consider purely transverse momentum transfer and, hence, obtain results describe only the proton’s two-dimensional structure in the transverse plane. We present the Mellin moments of these distribution functions, where the first moment produces a form factor and the second Mellin moments help extract the information on partonic contributions to the hadronic angular momentum. We compare our results for the Mellin moments with those from lattice QCD and other approaches where available. We also present the GPDs in transverse position space. Published by the American Physical Society 2024