Beam Spin Asymmetries of \(\pi ^{ + }\pi ^{0}\) Dihadrons from SIDIS at CLAS12

Abstract

Spin asymmetries provide a wide range of insights into nucleon structure and hadronization. Recent measurements of beam spin asymmetries of π + π − dihadrons from Semi-Inclusive Deep Inelastic Scattering (SIDIS) at CLAS12 provide the first empirical evidence of a nonzero G ⊥ 1 , the parton helicity-dependent Dihadron Fragmentation Function (DiFF) encoding spin-momentum correlations in hadronization. These measurements have been extended to aid in the characterization of H ⊥ 1 and H ∢ 1 , the DiFFs dependent on parton transverse spin, via a multidimensional partial wave analysis, giving access to the dependence on the interference of dihadrons of particular polarizations. Reconstruction of π 0 s allows for further extension of these measurements to π + π 0 and π − π 0 dihadrons. The DiFFs describing π + π − production differ from those describing π + π 0 and π − π 0 production, which involve different quark flavors along with a strong suppression of the exclusive diffractive contribution. This presentation will focus on beam spin asymmetries for π + π 0 dihadrons, compared to those from π + π − dihadrons, which will help shed light on a more comprehensive picture of dihadron fragmentation.