Hadronization geometry from net-charge angular correlations on momentum subspace ($η,ϕ$) in Au-Au collisions at $\sqrt{s_{NN}} = 130$ GeV

Abstract

We present the first measurements of charge-dependent correlations on angular difference variables $η_1 - η_2$ (pseudorapidity) and $ϕ_1 - ϕ_2$ (azimuth) for primary charged hadrons with transverse momentum $0.15 \leq p_t \leq 2$ GeV/$c$ and $|η| \leq 1.3$ from Au-Au collisions at $\sqrt{s_{NN}} = 130$ GeV. We observe correlation structures not predicted by theory but consistent with evolution of hadron emission geometry with increasing centrality from one-dimensional fragmentation of color strings along the beam direction to an at least two-dimensional hadronization geometry along the beam and azimuth directions of a hadron-opaque bulk medium.