
Christian Bierlich
Researcher, docent

Research
My research work revolves mainly around Monte Carlo simulation of hadronic collisions, and collisions of heavy ions. Mainly using the general purpose Monte Carlo event generator PYTHIA, of which I am a co-author. I am mainly interested in cases for collisions of "small systems", meaning for example protons, behave like collisions of heavy nuclei. In these cases the collisions exhibit so-called "collective behavior", where the emerging particles act as if they are produced by a single body of matter. The calculations used to describe this, involves multibody dynamics of Lund strings.
Outreach
I write popular articles on physics, in the magazine "Science Illustrated", see the literature list below. I am furthermore topic responsible for several sub-topics of high energy physics on the Danish National Encyclopedia. I also give the occasional outreach talk, contact me if you are interested.
IT
I am responsible for parts of the division IT, related to webpage administration as well as the Physics CodeLAB infrastructure. Feel free to drop me an email or to come by.
Publications
Displaying of publications. Sorted by year, then title.
Iterative HOMER with uncertainties
Anja Butter, Ayodele Ore, Sofia Palacios Schweitzer, Tilman Plehn, Benoît Assi, et al.
(2026) SciPost Physics, 20
ArticleGoing against the flow : Revealing the QCD degrees of freedom in hadronic collisions
Christian Bierlich, Peter Christiansen, Gösta Gustafson, Leif Lönnblad, Robin Törnkvist, et al.
(2026) Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 874
ArticleCharacterizing the hadronization of parton showers using the HOMER method
Benoît Assi, Christian Bierlich, Philip Ilten, Tony Menzo, Stephen Mrenna, et al.
(2025) SciPost Physics, 19
ArticlePost-hoc reweighting of hadron production in the Lund string model
Benoît Assi, Christan Bierlich, Philip Ilten, Tony Menzo, Stephen Mrenna, et al.
(2025) SciPost Physics, 19
ArticleSimplifying strangeness fluctuations through balance functions in proton–proton collisions
Christian Bierlich, Peter Christiansen
(2025) European Physical Journal C, 85
ArticleDescribing hadronization via histories and observables for Monte-Carlo event reweighting
Christian Bierlich, Phil Ilten, Tony Menzo, Stephen Mrenna, Manuel Szewc, et al.
(2025) SciPost Physics, 18
ArticleReweighting Monte Carlo predictions and automated fragmentation variations in Pythia 8
Christan Bierlich, Philip Ilten, Tony Menzo, Stephen Mrenna, Manuel Szewc, et al.
(2024) SciPost Physics, 16
ArticleString Interactions as a Source of Collective Behaviour
Christian Bierlich
(2024) Universe, 10
Review articleThe dynamic hadronization of charm quarks in heavy-ion collisions
Christian Bierlich, Gösta Gustafson, Leif Lönnblad, Harsh Shah
(2024) European Physical Journal C, 84
ArticleEvent generators for high-energy physics experiments
J.M. Campbell, C. Bierlich, S. Chakraborty, R. Frederix, L. Gellersen, et al.
(2024) SciPost Physics, 16
ArticleTowards a data-driven model of hadronization using normalizing flows
Christian Bierlich, Phil Ilten, Tony Menzo, Stephen Mrenna, Manuel Szewc, et al.
(2024) SciPost Physics, 17
ArticleA test of strangeness quantum number conservation in proton-proton collisions
Christian Bierlich, Stefano Cannito, Valentina Zaccolo
(2024) European Physical Journal C, 84
ArticleStrangeness enhancement across collision systems without a plasma
Christian Bierlich, Smita Chakraborty, Gösta Gustafson, Leif Lönnblad
(2022) Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 835
ArticleJet modifications from colour rope formation in dense systems of non-parallel strings
Christian Bierlich, Smita Chakraborty, Gösta Gustafson, Leif Lönnblad
(2022) SciPost Physics, 13
ArticleA comprehensive guide to the physics and usage of PYTHIA 8.3
Christian Bierlich, Smita Chakraborty, Nishita Desai, Leif Gellersen, Ilkka Helenius, et al.
(2022) SciPost Physics
ArticleHyperfine splitting effects in string hadronization
Christian Bierlich, Leif Lönnblad, Gösta Gustafson, Smita Chakraborty
(2022) European Physical Journal C. Particles and Fields
ArticleMultiparton interactions and underlying event : A PYTHIA perspective
Christian Bierlich
(2021) Proceedings of Science, 387
Paper in conference proceedingForbundne atomer holder tiden
Christian Bierlich
(2021) Illustreret Videnskab, 2021
Specialist publication articleAntistof kan sende fysikken i frit fald
Christian Bierlich
(2021) Illustreret Videnskab, 2021
Specialist publication articleSetting the string shoving picture in a new frame
Christian Bierlich, Smita Chakraborty, Gösta Gustafson, Leif Lönnblad
(2021) Journal of High Energy Physics
ArticleHadronic rescattering in pA and AA collisions
Marius Utheim, Christian Bierlich, Torbjorn Sjostrand
(2021) European Physical Journal A
ArticleRobust independent validation of experiment and theory : RIVET version 3
Christian Bierlich, Andy Buckley, Jonathan Butterworth, Christian Holm Christensen, Louie Corpe, et al.
(2020) SciPost Physics, 8
ArticleConfronting experimental data with heavy-ion models : Rivet for heavy ions
Christian Bierlich, Andy Buckley, Christian Holm Christensen, Peter Harald Lindenov Christiansen, Cody B. Duncan, et al.
(2020) European Physical Journal C, 80
ArticleNovel tools and observables for jet physics in heavy-ion collisions
Harry Arthur Andrews, Liliana Apolinario, Redmer Alexander Bertens, Christian Bierlich, Matteo Cacciari, et al.
(2020) Journal of Physics G: Nuclear and Particle Physics, 47
ArticleKvantemikrofon hører verdens mindste lyde
Christian Bierlich
(2020) Illustreret Videnskab, 2020
Specialist publication articleUniversets spejlbillede
Christian Bierlich
(2020) Illustreret Videnskab, 2020
Specialist publication articleQCD challenges from pp to A–A collisions
J. Adolfsson, A. Andronic, C. Bierlich, P. Bozek, S. Chakraborty, et al.
(2020) European Physical Journal A, 56
Review articleDipole evolution: perspectives for collectivity and γ*A collisions
Christian Bierlich, Christine Rasmussen
(2019) Journal of High Energy Physics
ArticleSoft modifications to jet fragmentation in high energy proton–proton collisions
Christian Bierlich
(2019) Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 795 p.194-199
ArticleStudying the Effect of the Hadronic Phase in Nuclear Collisions with PYTHIA and UrQMD
Christian Bierlich, André Vieira da Silva, D. D. Chinellato, Jun Takahashi
(2019) SQM 2019, 319-323
Paper in conference proceedingMicroscopic collectivity : The ridge and strangeness enhancement from string–string interactions
Christian Bierlich
(2019) Nuclear Physics A, 982 p.499-502
ArticleUltrapræcist atomur skal måle Jordens vægt
Christian Bierlich
(2019) Illustreret Videnskab, 2019
Specialist publication articleRope Hadronization and Strange Particle Production
Christian Bierlich
(2018) 17th International Conference on Strangeness in Quark Matter, SQM 2017, 171
Paper in conference proceedingCollectivity without plasma in hadronic collisions
Christian Bierlich, Gösta Gustafson, Leif Lönnblad
(2018) Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 779 p.58-63
ArticleThe Angantyr model for heavy-ion collisions in Pythia8
Christian Bierlich, Gösta Gustafson, Leif Lönnblad, Harsh Shah
(2018) Journal of High Energy Physics, 2018
ArticleFuture physics opportunities for high-density QCD at the LHC with heavy-ion and proton beams
Christian Bierlich, Y. Zhou
(2018) Future physics opportunities for high-density QCD at the LHC with heavy-ion and proton beams
Paper in conference proceedingNu kan vi teleportere data ud i rummet
Christian Bierlich
(2018) Illustreret Videnskab, 2018
Specialist publication articlePISTA: Posterior Ion STAcking
Johannes Bellm, Christian Bierlich
(2018) ArXiv e-prints
MiscellaneousSolsystemets miniputter
Christian Bierlich
(2017) Illustreret Videnskab, 2017
Specialist publication articleHvor bliver de af?
Christian Bierlich
(2017) Illustreret Videnskab, 2017
Specialist publication articleMultiparton interactions : From pp to pA
Christian Bierlich
(2017) Nuclear and Particle Physics Proceedings, 289-290 p.377-380
ArticleHadronisation models and colour reconnection
Christian Bierlich
(2016) Proceedings of Science, 11
Paper in conference proceedingRope Hadronization, Geometry and Particle Production in pp and pA Collisions
Christian Bierlich
(2016)
Doctoral Thesis (compilation)Diffractive and non-diffractive wounded nucleons and final states in pA collisions
Christian Bierlich, Gösta Gustafson, Leif Lönnblad
(2016) Journal of High Energy Physics, 2016
ArticleJagten på den niende planet
Christian Bierlich
(2016) Illustreret Videnskab, 2016
Specialist publication articleForskere fanger ekko fra sorte huller : Hvad er der inden i et sort hul?
Christian Bierlich
(2016) Illustreret Videnskab, 2016
Specialist publication articleA shoving model for collectivity in hadronic collisions
Christian Bierlich, Gösta Gustafson, Leif Lönnblad
(2016) arXiv.org, 1612
ArticleEffects of color reconnection on hadron flavor observables
Christian Bierlich, Jesper Roy Christiansen
(2015) Physical Review D (Particles, Fields, Gravitation and Cosmology), 92
ArticleEffects of overlapping strings in pp collisions
Christian Bierlich, Gösta Gustafson, Leif Lönnblad, Andrey Tarasov
(2015) Journal of High Energy Physics
Article