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Medium-induced QCD cascade: democratic branching and wave turbulence
J-P Blaizot1, E Iancu, Y Mehtar-Tani
1Institut de Physique Théorique Saclay, CNRS/URA2306, F-91191 Gif-sur-Yvette, France. jean-paul.blaizot@cea.fr
Physical Review Letters
|August 20, 2013
Summary
We investigated gluon cascades in quark-gluon plasma, finding that medium-induced emissions efficiently transport energy via quasidemocratic branchings. This turbulent flow explains excess soft energy observed in heavy-ion collisions.
Area of Science:
- High-energy particle physics
- Quantum Chromodynamics (QCD)
- Heavy-ion collisions
Background:
- Energetic partons interacting within a quark-gluon plasma (QGP) generate complex gluon cascades.
- Understanding energy transport at large angles is crucial for interpreting experimental data from heavy-ion collisions.
Purpose of the Study:
- To analyze the average properties of gluon cascades produced by energetic partons in a QGP.
- To investigate the role of soft, medium-induced gluon emissions in energy transport.
- To explore the phenomenon of quasidemocratic branching and its implications for turbulence.
Main Methods:
- Theoretical study of gluon cascade properties.
- Focus on soft, medium-induced emissions and multiple branching effects.
- Analysis of energy transport mechanisms and spectral properties.
Main Results:
- Medium-induced branchings in QGP are quasidemocratic, with offspring gluons carrying significant energy.
- This leads to an efficient energy transport mechanism resembling wave turbulence with a ~1/sqrt[ω] spectrum.
- Multiple branchings play a critical role in shaping the cascade.
Conclusions:
- The turbulent energy transport in gluon cascades provides a plausible explanation for excess soft energy observed in dijet asymmetry in Pb-Pb collisions at the LHC.
- Quasidemocratic branching is a key feature distinguishing QGP cascades from vacuum cascades.
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