Long-range near-side correlation in \(e^+e^-\) Collisions at 183-209 GeV with ALEPH Archived Data

• Published in: arXiv.org 2024-08
• Main Authors: Yu-Chen, Chen, Chen, Yi, Badea, Anthony, Baty, Austin, Innocenti, Gian Michele, Maggi, Marcello, McGinn, Christopher, Peters, Michael, Tzu-An Sheng, Thaler, Jesse, Yen-Jie, Lee
• Format: Article
• Language: English
• Subjects: Angular correlation; Charged particles; Fourier series; Kinematics; Mathematical analysis
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2312.05084

The first measurement of two-particle angular correlations for charged particles with LEP-II data is presented. The study is performed using archived hadronic \(e^+e^-\) data collected by ALEPH at center-of-mass energies up to 209 GeV, above the \(W^+W^-\) production threshold, which provide access to unprecedented charged-particle multiplicities and more complex color-string configurations if compared to previous measurements at LEP-I energies. An intriguing long-range near-side excess is observed in the correlation function measured with respect to the thrust axis in the highest multiplicity interval \(N_{\mathrm{trk}}\geq 50\). Such a structure is not predicted by the Monte-Carlo simulation. The harmonic anisotropy coefficients \(v_n\), which result from the Fourier expansion of the two-particle correlation functions, were also measured for the first time in \(e^+e^-\) data, and compared to PYTHIA6 predictions and to the results obtained in proton-proton collisions. The results presented in the Letter provide novel experimental constraints on the formation of collective phenomena in point-like \(e^+e^-\) collisions.