Multiparticle Collectivity from Initial State Correlations in High Energy Proton-Nucleus Collisions.

Area of Science:

• High Energy Nuclear Physics
• Quantum Chromodynamics
• Particle Physics

Background:

• Multiparticle correlations in high-energy collisions provide insights into the underlying physics.
• Interpreting these correlations in proton-nucleus (p+A) collisions is crucial for understanding nuclear matter.

Purpose of the Study:

• To reproduce qualitative features of multiparticle correlations in p+A collisions using a simplified initial state model.
• To offer an alternative explanation to hydrodynamic flow for observed correlation patterns.

Main Methods:

• Developed a simple initial state model involving coherent parton scattering off color charge domains.
• Analyzed azimuthal angle Fourier harmonics (v_n{2}) and four-particle correlations (v_2{4}).
• Investigated energy and transverse momentum dependencies, and symmetric cumulants.

Main Results:

• The model successfully reproduces the ordering of v_n{2} magnitudes and the energy/transverse momentum dependence of v_2{4}.
• Observed similar patterns in an Abelian version of the model, with v_2{2}>v_2{4}≈v_2{6}≈v_2{8}.
• The findings challenge the exclusive interpretation of these patterns as signatures of hydrodynamic flow.

Conclusions:

• A simple initial state model can explain key features of multiparticle correlations in p+A collisions.
• Coherent parton scattering provides a viable alternative mechanism to hydrodynamic flow.
• This work offers new perspectives on interpreting experimental data from RHIC and LHC.