PYTHIA status report
Recent improvements in the PYTHIA event generator are summarized: new hard subprocesses, γ*γ* physics, QCD final-state showers, and more.
The Lund Model
Preface 1. Relativistic kinematics, electromagnetic fields and the method of virtual quanta 2. The harmonic oscillator and the quantum field 3. The vacuum as a dielectric medium and renormalisation 4. Deep inelastic scattering and the parton model 5. The classical motion of the massless relativistic string 6. The decay kinematics of the massless relativistic string 7. A stochastic process for string decay 8. The properties of the Lund model fragmentation formulae: external part formulas 9. The internal part fragmentation formulae and their relations to the unitarity equations of Regge theory 10. The dynamical analogues of the Lund model fragmentation formulae 11. Flavour and transverse momentum generation, and the vector to pseudoscalar meson ratio 12. Heavy quark fragmentation and Baryon production 13. The Hanbury-Brown-Twiss-effect and polarisation in the Lund model 14. The Lund gluon model, the kinematics and the decay properties 15. Gluon emission via the Bremsstrahlung process 16. Multigluon emission, the dipole moment and parton coherence cascade models 17. The lambda measure in the leading log, and the modified lead log approximation of perturbative QCD 18. The parton model and QCD 19. Inelastic lepto-production in the Lund model, the soft radiation model and heretical structure functions 20. Hadronic interaction models References Index.
A model for the reaction mechanism and the baryon fragmentation distributions in low p⊥ hadronic interactions
Abstract We present a reaction mechanism, based on a semiclassical treatment of color dynamics together with the corresponding results for the final state in a low p ⊥ hadronic interaction. The ensuing model is of fragmentation character (like the one presented on phenomenological grounds in refs. [1, 2]) and the final-state hadrons stem from the breakup of an essentially one-dimensional color force field in a way similar to the models for soft hadronisation of colored objects that we have developed for use in leptoproduction and e + e − annihilation. We present a set of predictions from the model for baryon fragmentation distributions in low p ⊥ reactions which is in good agreement with the present experimental data and also contains some non-trivial correlation properties that can be tested in the next generation of experiments.