Title: Energy Correlators within Jets in Transversely Polarized Proton Proton Collisions at 200 GeV

PA: Ting Lin

Target Journal: Phys. Rev. Lett.

Abstract:  We present the first measurement of one- and two-point energy–energy correlators (EEC) within jets in transversely polarized proton proton collisions at 200 GeV. The one-point EEC correlates the jet axis with a single hadron, while the two-point EEC measures the relative azimuth between hadron pairs in jet, both weighted by hadron momentum fractions. Spin-dependent asymmetries are observed for pi+, pi-− and pi+pi− in jet, providing direct sensitivity to higher-order Mellin moments of transverse spin–dependent fragmentation functions and probing the transition from the perturbative to the nonperturbative regime of QCD. These results provide unique constraints on spin–momentum correlations in hadronization, establish EEC as a new tool to probe the transverse spin effects in QCD.

Paper Draft: In preparation

Analysis Note:

Figure 1: Definition of one- and two-point EEC in jet

Figure 2: Asymmetry vs. phi_S - phi_{h/hh}

Figure 3: Asymmetry vs. Jet Pt

Figure 4: Asymmetry vs. theta