An Impact Study on the Pion Structure Measurement at EicC.

An Electron-ion collider in China (EicC) has recently been proposed, for imaging the precise and detailed internal structures of hadrons, understanding the emergent properties of nucleon (such as the nucleon mass and spin) and the emergence of nuclear medium effect, and studying the exotic hadronic states. By exploiting the abundant “pion cloud” around the proton, an experiment of measuring the pion structure is suggested, and it is one of the physics highlights at the EicC facility. In this paper, we present a simulation study of the proposed pion structure experiment. At EicC, the pion structure information is accessed via the leading-neutron tagged deep inelastic scattering—the widely acknowledged Sullivan process of pion exchange with small momentum transfer. We briefly discuss the theoretical framework of our event generator and the current design of the experimental setup for the experiment. We then evaluate the statistical errors of the pion structure function that would be extracted from the proposed measurement under the integrated luminosity of 50 fb - 1 . The sensitivity and precision to pion parton distribution functions are also demonstrated with a global fit. The precise quark distributions of the pion can be achieved at EicC in the range of 0.05 < x π < 0.95 , and the pion gluon distribution also can be constrained by the global fit of the pseudo-data at various Q 2 . [ABSTRACT FROM AUTHOR]