Speaker: Prof. Wen-Chen Chang (AS)
Talk title: Pion and Kaon PDFs
Time: 2025/04/21 (Mon.) 12:30
Place: NCTS Physics 4F Lecture Hall, Cosmology Hall, NTU

Abstract: 
The pion, as the Goldstone boson of dynamical chiral symmetry breaking of the strong interaction, is the lightest QCD bound state. Because of its light mass, pion plays a dominant role in the long-range nucleon-nucleon interaction. Understanding the internal structure is important to investigate the low energy, non-perturbative aspects of QCD. Nevertheless, the uncertainties of partonic density functions (PDFs) of pions are relatively huge, because of the lack of rest pion targets.

In this talk, we review recent experimental and theoretical progress on extracting the pion PDFs. Furthermore, we will provide quantitative evidence within the CEM and NRQCD frameworks that the existing pion-induced fixed-target J/psi and psi (2S) data are sensitive to the gluon density of pions and favor the pion PDFs with relatively large gluon contents at large x. The recent work of extending the study to the poorly known kaon PDFs will be reported.

References:
[1] W.C. Chang, J.C. Peng, S. Platchkov, and T. Sawada, Phys. Rev. D 102, 054024 (2020); arXiv:2006.06947.
[2] C.Y. Hsieh, Y.S. Lian, W.C. Chang, J.C. Peng, S. Platchkov, and T. Sawada, Chin. J. Phys. 73, 13 (2021); arXiv:2103.11660.
[3] W.C. Chang, J.C. Peng, S. Platchkov, and T. Sawada, Phys. Rev. D 107, 056008 (2023); arXiv: 2209.04072.
[4] W.C. Chang, J.C. Peng, S. Platchkov, and T. Sawada, Phys. Lett. B 855, 138820 (2024); arXiv: 2402.02860.