Motivation

The first meeting of the Saturated Glue (SURGE) Topical Collaboration.

Collaboration mission: Discover and explore the gluon saturation regime of quantum chromodynamics by advancing calculations to high precision and developing a comprehensive framework to compute observables and compare to a wide range of experimental data, including predictions for the Electron Ion Collider (EIC).

Collaboration Goals

• Identify observables that are sensitive to gluon saturation in polarized and unpolarized proton-nucleus collisions (p + A), ultraperipheral heavy ion and p + A collisions, in DIS off polarized protons or light nuclei (e + p), and in DIS off heavy nuclei (e + A).
• Provide robust end-to-end calculations minimizing known uncertainties for each of these observables with an ambitious goal of < 10% accuracy, sufficient for unambiguous characterization of the gluon dominated small x regime in protons and nuclei.
• Incorporate results in a novel global analysis framework for data-theory comparisons that can be systematically improved to cleanly establish evidence for a universal gluon saturation regime in QCD.
• Explore the larger implications of the ideas and techniques developed during the project and their interdisciplinary connections.

A realistic goal in small x studies is 10% accuracy. This is driven by the fact that process-dependent so-called “impact factors” for key final states are progressing towards next-to-leading order (NLO) accuracy; likewise, there is progress in computing small-x evolution equations to next-to-leading logarithmic accuracy. We will also discuss reducing uncertainties in initial conditions, spin dynamics and parton fragmentation to this required level.

Topics or Session Information

• Initial state
• Small x evolution and next-to-leading order calculations
• Spin
• Final state
• Framework and global analysis