University of Jyväskylä

Dissertation: 15.12.2017 Jet fragmentation transverse momentum from h-h correlations in pp and p-Pb collisions (Viinikainen)

Start date: Dec 15, 2017 12:00 PM

End date: Dec 15, 2017 03:00 PM

Location: Ylistönrinne, FYS1

Jussi Viinikainen
M.Sc. Jussi Viinikainen defends his doctoral dissertation in Physics "Jet fragmentation transverse momentum from h-h correlations in pp and p-Pb collisions". Opponent Professor Gunther Roland (Massachusetts Institute of Technology) and custos Professor Jan Rak (University of Jyväskylä). The doctoral dissertation is held in English.


We study the transverse structure of jets via jet fragmentation transverse momentum distributions obtained using two particle correlations in proton-proton and proton-lead collisions measured with the ALICE experiment at the CERN LHC. The measured distributions show clear narrow Gaussian and wide non-Gaussian components. Based on PYTHIA simulations, we argue that the narrow component can be related to non-perturbative hadronization and the wide component to quantum chromodynamical splitting. We further show that the trigger transverse momentum dependence of the width of the narrow component is small in accordance with the assumption of universality of the hadronization process. On the other hand, the wide component width shows a rising trend suggesting increased branching with increasing trigger momentum. The results obtained in pp collisions at the center-of-mass energy of 7 TeV and in p-Pb collisions at the center-of-mass energy per nucleon of 5.02 TeV are the same within the uncertainties and hence no significant cold nuclear matter effects are observed. The obtained results are compared to previous measurements from CCOR and PHENIX as well as to PYTHIA 8 and Herwig 7 simulations.

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M.Sc. Jussi Viinikainen
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