The standard for parton distribution function (PDF) fits is at next-to-next-to-leading order (NNLO) in the strong coupling constant ($\alpha_{s}$). However, as we move into a new era of high precision phenomenology, experimental physics is pushing the need for a robust understanding of theoretical uncertainties to new levels. Due to the perturbative nature of calculations in Quantum...
The Electron Ion Collider (EIC) to be built by JLab and BNL will be unique in colliding polarized electrons off polarized protons and light nuclei, providing the spin degrees of freedom essential to pursue its physics program to study spin structure, multi-dimensional tomographic images of protons and nuclei, and collective effects of gluons in nuclei. The unprecedented luminosity of the EIC,...
In this presentation I will talk about a novel contribution to the transverse single spin asymmetry (TSSA) from the gT(x) distribution of the transversely polarized proton [1,2]. I will explain how this contribution, absent at the Born level, first appears at two loops and outline the key ideas in the derivation. Next, I will show the detailed results in SIDIS for all possible harmonics of the...
At BESIII, the R value is measured with a total of 14 data points with the corresponding c.m. energy going from 2.2324 to 3.6710 GeV.
The statistical uncertainty of the measured R is less than 0.6%. Two different simulation models, the LUARLW and a new Hybrid generated, are used and give consistent detection efficiencies and initial-state-radiation corrections. An accuracy of better than 2.6%...
