The Universal Nature of Transversity PDFs and the Tensor Charges of the Nucleon

The transversity parton distribution functions (PDFs), which quantify the degree of transverse polarization of quarks within a transversely polarized nucleon, have been a focus of QCD phenomenology for decades. Two approaches to extracting these functions are through transverse momentum dependent (TMD) and/or collinear twist-3 (CT3) observables as well as the use of collinear factorization with dihadron fragmentation functions (DiFFs). The transversity PDFs are also of interest since they allow one to calculate the tensor charges of the nucleon. The tensor charges are important in low-energy beyond the Standard Model studies and also have been computed very precisely in lattice QCD. In this talk, I will report on new developments in the theory and phenomenology of DiFFs in extracting the transversity PDFs and discuss their compatibility with the TMD/CT3 approach as well as lattice QCD computations of the nucleon tensor charges.