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Picture of Christian Bierlich

Christian Bierlich


Picture of Christian Bierlich

Rope Hadronization, Geometry and Particle Production in pp and pA Collisions


  • Christian Bierlich

Summary, in English

This thesis concerns models of high energy collisions of sub-atomic particles, and the models’ implementation in numerical simulations; so–called Monte Carlo event generators. The models put forth in the thesis improves the description of soft collisions of protons, and takes the first steps towards a new, microscopic description of collectivity in proton collisions and collisions of heavy nuclei such as lead.
Paper I. The Lund string hadronization model is reviewed, and a model for corrections in busy environments, such as pp minimum bias, are introduced, and its implementation in the event generator DIPSY is described. The model affects the hadrochemistry of the underlying event, and improves description of existing pp data from LHC and RHIC.
Paper II. A series of new observables sensitive to effects from rope hadronization is introduced, and predictions of the rope hadronization model is compared to predictions from a similar model based on junction formation.
Paper III. The Glauber formalism for collisions of nuclei is reviewed, and contributions from diffraction are considered. The Glauber–Gribov formalism for colour fluctuations is compared to the DIPSY model. On the basis of this comparision, corrections to the Glauber–Gribov parametrization of the pp cross section are suggested.
This corrected formalism is then coupled to a particle production model, and preliminary descriptions of particle production in pA is given.
Paper IV. A model for string–shoving, expanding on the model from Paper I, is introduced at the proof–of–concept level. It is shown that the model qualitatively produces a rise of mean-p ⊥ with hadron mass and long range azimuthal correlations in pp collisions.


  • Theoretical Particle Physics

Publishing year




Document type



Lund University, Faculty of Science, Department of Astronomy and Theoretical Physics


  • Subatomic Physics


  • QCD
  • Phenomenology
  • Hadronization
  • Heavy ion collisions
  • Fysicumarkivet A:2016:Bierlich




  • Leif Lönnblad
  • Torbjörn Sjöstrand


  • ISBN: 978-91-7753-149-4
  • ISBN: 978-91-7753-148-7

Defence date

27 January 2017

Defence time


Defence place

Lundmark lecture hall, Lund Observatory, Sölvegatan 27, Lund


  • Klaus Werner (Professor)