The space-time structure of hadronization in the Lund model

Area of Science:

• High Energy Physics
• Quantum Chromodynamics (QCD)
• Particle Phenomenology

Background:

• The Lund string model traditionally describes particle fragmentation using an energy-momentum picture.
• Extending this to complex systems and incorporating a space-time picture has been challenging.
• Previous models primarily focused on the energy-momentum aspects of hadronization.

Purpose of the Study:

• To develop and implement a space-time picture of hadronization within the Lund string model.
• To investigate hadron production density in various complex systems, including LHC events.
• To provide a framework for understanding collective behavior in high-multiplicity collisions.

Main Methods:

• Development of the space-time picture for open/closed multiparton topologies, junction systems, and massive quarks.
• Integration of the new framework into the Pythia event generator.
• Quantification of hadron production density under diverse conditions using toy and LHC event simulations.

Main Results:

• The study successfully elaborates the space-time picture of fragmentation for complex systems.
• Calculations reveal potentially high densities of hadron production in simulated events.
• Results are validated using both simplified toy systems and realistic Large Hadron Collider (LHC) event data.

Conclusions:

• The high hadron production density observed motivates the collective behavior seen in high-multiplicity proton-proton (pp) collisions.
• The developed space-time framework offers a significant advancement for particle physics event generators like Pythia.
• This provides a foundation for future model developments, including aspects like hadronic rescattering.