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Production of φ Mesons as a Function of Multiplicity & Spherocity


Summary, in English

The purpose of this project is to further investigate whether the collective behavior observed in
high energy proton-proton (p-p) collision can be attributed to the formation of Quark-Gluon Plasma
(QGP). This is done by measuring the production rate of the strange φ meson in high multiplicity
p-p collisions at √sNN = 13 TeV. The high multiplicity p-p events are then divided into different
transverse spherocity bins, in order to gauge whether the φ production is dominated by events that
are geometrically characterized as jet-like or isotropic. The results, although leaving some questions to
be asked regarding the simulated detector efficiency, present a pronounced enhancement of φ mesons
in high multiplicity collisions, and further state that the strangeness enhancement is dominated by
events with an overall isotropic shape. These findings suggest that Lund string-like models might
be inadequate at fully describing high multiplicity p-p collisions. It also gives further support to the
idea that the preferred mechanism of φ particle production might follow a statistical, hydrodynamical
model, through the formation of a QGP phase.

Publishing year




Document type

Student publication for Master's degree (two years)


  • Physics and Astronomy


  • Peter Christiansen