Tensor-polarized structure function b1 in the standard convolution description of the deuteron

Tensor-polarized structure functions of a spin-1 hadron are additional observables, which do not exist for the spin-1/2 nucleon. They could probe novel aspects of the internal hadron structure. Twist-2 tensor-polarized structure functions are b(1) and b(2), and they are related by the Callan-Gross-like relation in the Bjorken scaling limit. In this work, we theoretically calculate b(1) in the standard convolution description for the deuteron. Two different theoretical models, a basic convolution description and a virtual nucleon approximation, are used for calculating b(1), and their results are compared with the HERMES measurement. We found large differences between our theoretical results and the data. Although there is still room to improve by considering higher-twist effects and in the experimental extraction of b(1) from the spin asymmetry A(zz), there is a possibility that the large differences require physics beyond the standard deuteron model for their interpretation. Future b(1) studies could shed light on a new field of hadron physics. In particular, detailed experimental studies of b(1) will start soon at the Thomas Jefferson National Accelerator Facility. In addition, there are possibilities to investigate tensor-polarized parton distribution functions and b(1) at Fermi National Accelerator Laboratory and a future electron-ion collider. Therefore, further theoretical studies are needed for understanding the tensor structure of the spin-1 deuteron, including a new mechanism to explain the large differences between the current data and our theoretical results.