Exploring the Collective Phenomenon at the Electron-Ion Collider

Abstract

Based on rare fluctuations in strong interactions, we argue that there is a strong physical resemblance between the high multiplicity events in photo-nuclear collisions and those in pA collisions, in which interesting long range collective phenomena are discovered. This indicates that the collectivity can also be studied in certain kinematic region of the upcoming Electron-Ion Collider (EIC) where the incoming virtual photon has a sufficiently long lifetime. Using a model in the Color Glass Condensate formalism, we first show that the initial state interactions can explain the recent ATLAS azimuthal correlation results measured in the photo-nuclear collisions, and then we provide quantitative predictions for the long range correlations in eA collisions in the EIC regime. With the unprecedented precision and the ability to change size of the collisional system, the high luminosity EIC will open a new window to explore the physical mechanism responsible for the collective phenomenon.

Measurement of Two-Particle Correlations of Hadrons in $e^{+}e^{-}$ Collisions at Belle

“…No significant ridge-like signal was observed in these measurements. These results have stimulated discussions on the ways to search for and understand possible collectivity signatures in e + e − [27][28][29] and electron-ion collisions [30,31]. However, the data samples used for the search in the e + e − ALEPH archived data [26] is small, which motivates the examination of a high-statistics data to study the highest multiplicity tail at Belle.…”