Exploring jets with respect to the reaction plane in heavy-ion collisions with XSCAPE
(2025) FYSK04 20251Particle and nuclear physics
Department of Physics
- Abstract
- The aim of this thesis is to explore jets traversing the Quark-Gluon Plasma (QGP)created in Pb-Pb collisions. This is done in the simulation program XSCAPE with a center of mass energy of 2.76 TeV. By categorising the jets by their azimuthal angle with respect to the event plane angle, the path length dependence of the energy loss was studied. The path length classification was described with the energy density through which a jet passes, as well as the jet’s number of interactions in the QGP. Event shape engineering was used to classify the ellipticity of the collision and obtain a sample of events with an elliptically shaped QGP to work with, where a difference in path would be present, and a set of events with a spherically shaped QGP... (More)
- The aim of this thesis is to explore jets traversing the Quark-Gluon Plasma (QGP)created in Pb-Pb collisions. This is done in the simulation program XSCAPE with a center of mass energy of 2.76 TeV. By categorising the jets by their azimuthal angle with respect to the event plane angle, the path length dependence of the energy loss was studied. The path length classification was described with the energy density through which a jet passes, as well as the jet’s number of interactions in the QGP. Event shape engineering was used to classify the ellipticity of the collision and obtain a sample of events with an elliptically shaped QGP to work with, where a difference in path would be present, and a set of events with a spherically shaped QGP as a reference. It followed that the classification of the ellipticity did not change the collision area of the peripheral events used. Jets traveling out-of-plane have less transverse momentum than in-plane jets and therefore seem to have undergone more jet quenching. The quenching is also more prominent for jets with lower momentum. The thesis shows similar results to previous studies of next to no path length dependency. This project found that the energy density showed a dependence on the path length concealed by fluctuations in the medium and the fragmentation of the jets. (Less)
- Popular Abstract
- Everything we can touch in the universe consists of atoms. In turn, these atoms are built up by protons, neutrons and electrons, a fact many know from high school. Interestingly, this is not the end of the line, protons and neutrons have some building blocks inside them as well. These building blocks, called quarks and gluons, are confined inside the protons and neutrons and can not be found on their own, or so we thought. In the early 2000s, scientists found that in high-energy collisions between two heavy ions, a hot and dense medium, which later got the name Quark-Gluon Plasma, was being formed. When exploring the Quark-Gluon Plasma, scientists found that quarks and gluons disconnected from the protons and neutrons and could roam more... (More)
- Everything we can touch in the universe consists of atoms. In turn, these atoms are built up by protons, neutrons and electrons, a fact many know from high school. Interestingly, this is not the end of the line, protons and neutrons have some building blocks inside them as well. These building blocks, called quarks and gluons, are confined inside the protons and neutrons and can not be found on their own, or so we thought. In the early 2000s, scientists found that in high-energy collisions between two heavy ions, a hot and dense medium, which later got the name Quark-Gluon Plasma, was being formed. When exploring the Quark-Gluon Plasma, scientists found that quarks and gluons disconnected from the protons and neutrons and could roam more or less freely. They found that this medium was like a liquid with a viscosity lower than any material, so low in fact, that it’s almost considered a perfect liquid.
Quarks and gluons interact with the Quark-Gluon Plasma and lose energy. Many searches for understanding the behavior of the Quark Gluon Plasma have been made. Intuitively, it would be expected that as a particle travels further in the medium, the energy loss will increase. Previous studies have seen indications of this path dependence. However, the need for a deeper understanding is relevant. This project aims to explore high energy particles traveling in the Quark-Gluon Plasma. What we hope to gain is finding a path dependence on the loss of energy particles have, by comparing different lengths that the particles travel through the medium. This will be done in simulation and in doing so, offer a deeper understanding of the inner workings of the medium.
It was found that a path dependence is present, however fluctuations are impacting the result to an extent that this dependence is rather hidden. Think of yourself standing in a courtyard. The time it takes you to cross the courtyard depends on the size (path of particle) and how fast you walk (energy of particle). However, if the courtyard is filled with people, another aspect influences how fast you reach your destination. As you walk, you will bump into people and it will take longer to reach your destination than without them around you. As a particle travels in the Quark-Gluon Plasma, it sees the medium a little like you see the people in the courtyard. The longer of a medium a particle passes through, the more energy it will lose. However, depending on the fluctuations in the density (the amount of people) of the medium, this path dependence can be hidden. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9208241
- author
- Brandt Sahlberg, Ellen LU
- supervisor
-
- Alice Ohlson LU
- organization
- course
- FYSK04 20251
- year
- 2025
- type
- M2 - Bachelor Degree
- subject
- language
- English
- id
- 9208241
- date added to LUP
- 2025-07-15 13:40:02
- date last changed
- 2025-07-15 13:40:02
@misc{9208241,
abstract = {{The aim of this thesis is to explore jets traversing the Quark-Gluon Plasma (QGP)created in Pb-Pb collisions. This is done in the simulation program XSCAPE with a center of mass energy of 2.76 TeV. By categorising the jets by their azimuthal angle with respect to the event plane angle, the path length dependence of the energy loss was studied. The path length classification was described with the energy density through which a jet passes, as well as the jet’s number of interactions in the QGP. Event shape engineering was used to classify the ellipticity of the collision and obtain a sample of events with an elliptically shaped QGP to work with, where a difference in path would be present, and a set of events with a spherically shaped QGP as a reference. It followed that the classification of the ellipticity did not change the collision area of the peripheral events used. Jets traveling out-of-plane have less transverse momentum than in-plane jets and therefore seem to have undergone more jet quenching. The quenching is also more prominent for jets with lower momentum. The thesis shows similar results to previous studies of next to no path length dependency. This project found that the energy density showed a dependence on the path length concealed by fluctuations in the medium and the fragmentation of the jets.}},
author = {{Brandt Sahlberg, Ellen}},
language = {{eng}},
note = {{Student Paper}},
title = {{Exploring jets with respect to the reaction plane in heavy-ion collisions with XSCAPE}},
year = {{2025}},
}