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"Ridge" in proton-proton scattering at 7 TeV
K Werner1, Iu Karpenko, T Pierog
1SUBATECH, University of Nantes-IN2P3/CNRS-EMN, Nantes, France.
Physical Review Letters
|April 27, 2011
Summary
Researchers observed a "ridge" structure in proton-proton scattering at the LHC. Hydrodynamical expansion naturally explains this structure, suggesting fluid-like behavior in particle collisions.
Area of Science:
- High-energy particle physics
- Quantum chromodynamics
- Heavy-ion collisions
Background:
- The Large Hadron Collider (LHC) has observed a significant "ridge" structure in two-particle correlation functions during proton-proton scattering experiments.
- This structure is characterized by a strong correlation at zero azimuthal angle difference (Δφ=0) extending over a large pseudorapidity difference (Δη).
Purpose of the Study:
- To investigate the origin of the "ridge" structure observed in proton-proton scattering at the LHC.
- To determine if hydrodynamical expansion can naturally explain the observed correlation patterns.
Main Methods:
- Event-by-event hydrodynamical expansion calculations were performed.
- Flux tube initial conditions were utilized to model the particle interactions.
- The study focused on statistical fluctuations in initial conditions and subsequent collective expansion.
Main Results:
- The hydrodynamical expansion model, using flux tube initial conditions, successfully reproduces the observed "ridge" structure.
- The model naturally explains the strong correlation at Δφ=0 and its extension in Δη.
- Event-by-event calculations are crucial for capturing the effect of initial condition fluctuations.
Conclusions:
- The results provide strong evidence for fluid-like behavior in proton-proton scattering, even at small length scales (around 0.1 fm).
- Collective expansion plays a significant role in shaping the observed correlation structures.
- This finding supports the applicability of hydrodynamical models beyond traditional heavy-ion collisions.
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