Investigating RT using two-particle angular correlations in proton-proton collisions
(2020) FYSK02 20201Particle and nuclear physics
Department of Physics
- Abstract
- The observable, RT , is investigated using two-dimensional (∆η, ∆φ) angular correlations, where ∆η and ∆φ are the differences in pseudorapidity and azimuthal angle respectively, between the trigger and associated tracks. The analysed data consists of reconstructed tracks, from proton-proton collisions at collision energy ps = 13 TeV, taken from the ALICE detector at the LHC. Correlations are constructed in three configurations, where the selection of trigger and associated tracks is changed. Analysis of the correlations imply that RT has high sensitivity to the underlying event, as well as a tendency to select event shapes with dominating back-toback jet fragmentation for low RT. A disappearance of the away-side peak in ∆φ-projections is... (More)
- The observable, RT , is investigated using two-dimensional (∆η, ∆φ) angular correlations, where ∆η and ∆φ are the differences in pseudorapidity and azimuthal angle respectively, between the trigger and associated tracks. The analysed data consists of reconstructed tracks, from proton-proton collisions at collision energy ps = 13 TeV, taken from the ALICE detector at the LHC. Correlations are constructed in three configurations, where the selection of trigger and associated tracks is changed. Analysis of the correlations imply that RT has high sensitivity to the underlying event, as well as a tendency to select event shapes with dominating back-toback jet fragmentation for low RT. A disappearance of the away-side peak in ∆φ-projections is observed in high RT events. We also see significant near-side correlations in all configurations, even within the transverse region. (Less)
- Popular Abstract
- Studying the first moments of the universe is a very hard task. How does one even start? One of the methods used for this task is to try to recreate the conditions of the early universe. Back then, the universe was much smaller but still contained everything that exists in our universe today. This means that everything was tightly packed together, causing higher energy densities and temperatures. At these high energies, atoms cannot form since not even the protons and neutrons themselves can form. This is because the constituents of the protons and neutrons, the quarks and gluons, now form a plasma and cannot bind exclusively to each other. This plasma is called the Quark Gluon Plasma (QGP).
The Large Hadron Collider (LHC) is a large... (More) - Studying the first moments of the universe is a very hard task. How does one even start? One of the methods used for this task is to try to recreate the conditions of the early universe. Back then, the universe was much smaller but still contained everything that exists in our universe today. This means that everything was tightly packed together, causing higher energy densities and temperatures. At these high energies, atoms cannot form since not even the protons and neutrons themselves can form. This is because the constituents of the protons and neutrons, the quarks and gluons, now form a plasma and cannot bind exclusively to each other. This plasma is called the Quark Gluon Plasma (QGP).
The Large Hadron Collider (LHC) is a large particle accelerator, the largest in the world, which is used to collide particles like protons and ionized atoms. These collisions are highly energetic, due to the extremely high acceleration of the LHC (close to the speed of light). The collision events do not last for a long time, but during these events the conditions are similar to the conditions of the early universe.
There are four detectors built into the LHC, these detectors are placed where the collisions take place. These detectors measure many different things, from the speed of the collision fragments to the number of fragments and their distributions. All this data must be saved and analysed. And it is a lot of data.
One can look at the distribution of the particle fragments of the collisions. Specifically, the distributions of the fragments relative to the fastest particles. Because it is believed that the fast fragments are not part of the possible QGP, but rather the particles that are perpendicular to these “jets” of fast fragments. When the QGP cools down, the quarks and gluons are no longer free and have bound themselves to particles like protons and neutrons.
An ongoing study is trying to use the ratio of particles in the perpendicular (transverse) region (figure 1) relative to the average number of particles in the transverse region for all recorded events, to try to classify and categorize events. Using this categorization can help scientists to analyse and select interesting events. Especially in the study of the QGP. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9026184
- author
- Chroscik, Dilan LU
- supervisor
- organization
- course
- FYSK02 20201
- year
- 2020
- type
- M2 - Bachelor Degree
- subject
- keywords
- particle physics, proton-proton collisions, two-particle angular correlations, underlying event, relative transverse activity, ALICE, LHC, collective flow, long range correlations
- language
- English
- id
- 9026184
- date added to LUP
- 2020-08-17 08:51:51
- date last changed
- 2020-08-17 08:51:51
@misc{9026184,
abstract = {{The observable, RT , is investigated using two-dimensional (∆η, ∆φ) angular correlations, where ∆η and ∆φ are the differences in pseudorapidity and azimuthal angle respectively, between the trigger and associated tracks. The analysed data consists of reconstructed tracks, from proton-proton collisions at collision energy ps = 13 TeV, taken from the ALICE detector at the LHC. Correlations are constructed in three configurations, where the selection of trigger and associated tracks is changed. Analysis of the correlations imply that RT has high sensitivity to the underlying event, as well as a tendency to select event shapes with dominating back-toback jet fragmentation for low RT. A disappearance of the away-side peak in ∆φ-projections is observed in high RT events. We also see significant near-side correlations in all configurations, even within the transverse region.}},
author = {{Chroscik, Dilan}},
language = {{eng}},
note = {{Student Paper}},
title = {{Investigating RT using two-particle angular correlations in proton-proton collisions}},
year = {{2020}},
}