Multiparton Interaction Models and Parton Shower Studies
(2011)- Abstract
- This thesis involves phenomenological models for describing high energy
particle collisions. One class of these models, multiparton interactions
(MPI), deals with the fact that when colliding two hadrons, it is possible
for more than one pair of their constituents to interact. The other deals
with parton showers, which are used to fill enhanced regions of phase space
and give fully exclusive final states. These two components, when part of
an event generation framework, help in the simulation of complete high
energy collision events.
Paper I presents a study of an extension to the MPI model, enhanced
screening, where the amount of colour screening in... (More) - This thesis involves phenomenological models for describing high energy
particle collisions. One class of these models, multiparton interactions
(MPI), deals with the fact that when colliding two hadrons, it is possible
for more than one pair of their constituents to interact. The other deals
with parton showers, which are used to fill enhanced regions of phase space
and give fully exclusive final states. These two components, when part of
an event generation framework, help in the simulation of complete high
energy collision events.
Paper I presents a study of an extension to the MPI model, enhanced
screening, where the amount of colour screening in an incoming hadron is
increased in those events with a large amount of activity.
Paper II presents another extension to the MPI model, rescattering.
Commonly, in MPI models, interactions are between pairs of partons which
originate from the incoming hadrons. With rescattering, an MPI can instead
involve partons which come from previous interactions or shower
branchings.
Paper III studies the first emission of the parton shower. First, the
interface to a next-to-leading generator, POWHEG-hvq, is examined.
Second, a dampening of the first shower emission, based on general matrix
element arguments is studied.
Paper IV again deals with parton showers. Minor changes to the framework
are outlined, before a kinematic comparison of the shower is made against
2 to 3 QCD real emission matrix elements. Finally, tunes of the
generator are made to both Tevatron and LHC data.
Paper V examines an extension to the impact parameter formalism of the MPI
model, where the size of an incoming proton is varied depending on the
x value of a parton being taken from it. (Less) - Abstract (Swedish)
- Popular Abstract in English
Experiments, such as the Large Hadron Collider (LHC) in CERN, Switzerland,
collide particles together at high energies, in the hope of probing the
fundamental constituents and forces of nature. On the theoretical side, the
Standard Model (SM) is currently the best description we have. It is a
theory that encompasses the strong, weak and electromagnetic forces,
although excludes gravity. This thesis deals with topics related to Monte
Carlo event generators; tools which, based on the theory, simulate these
particle collisions, and give us an idea of what to expect at particle
physics experiments.
When protons... (More) - Popular Abstract in English
Experiments, such as the Large Hadron Collider (LHC) in CERN, Switzerland,
collide particles together at high energies, in the hope of probing the
fundamental constituents and forces of nature. On the theoretical side, the
Standard Model (SM) is currently the best description we have. It is a
theory that encompasses the strong, weak and electromagnetic forces,
although excludes gravity. This thesis deals with topics related to Monte
Carlo event generators; tools which, based on the theory, simulate these
particle collisions, and give us an idea of what to expect at particle
physics experiments.
When protons are made to collide, as at the LHC, much of the physics will
be dominated by the strong force. The part of the SM that describes this is
known as Quantum Chromo Dynamics (QCD). It is not currently possible to
solve this theory exactly, and many approximate methods are used. This
thesis, in part, relates to parton showers, which describe the phenomenon
that quarks and gluons (collectively known as partons, and the constituents
of hadrons, such as the proton), can radiate other quarks and gluons, and
in fact do so copiously under certain conditions.
The other part of this thesis deals with multiparton interaction (MPI)
models. MPI is a consequence of the composite nature of hadrons.
For example, a proton is made up from three quarks, and will also contain
many gluons which in turn can split into further quark-antiquark pairs.
When two protons collide, it is hoped that one parton from each will
interact together, but it is also possible for more than one pair to do so.
These MPI affect the results from collider experiments, and so it is vital
to have good models for them, such that their effect can be understood and
disentangled from the data. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1787237
- author
- Corke, Richard LU
- supervisor
- opponent
-
- Professor Cacciari, Matteo, LPTHE, UPMC Univ. Paris 6, France and Université Paris Diderot, France
- organization
- publishing date
- 2011
- type
- Thesis
- publication status
- published
- subject
- keywords
- Multiparton Interactions, Parton Showers, Phenomenological Models, QCD Phenomenology
- pages
- 211 pages
- publisher
- Department of Astronomy and Theoretical Physics, Lund University
- defense location
- Lecture Hall F, Department of Astronomy and Theoretical Physics, Sölvegatan 14A, Lund, Sweden
- defense date
- 2011-03-11 10:15:00
- ISBN
- 978-91-7473-087-6
- language
- English
- LU publication?
- yes
- id
- 6f55eea6-7de0-4ece-9792-73ed6f5b3b78 (old id 1787237)
- date added to LUP
- 2016-04-04 10:13:12
- date last changed
- 2018-11-21 20:57:30
@phdthesis{6f55eea6-7de0-4ece-9792-73ed6f5b3b78, abstract = {{This thesis involves phenomenological models for describing high energy<br/><br> particle collisions. One class of these models, multiparton interactions<br/><br> (MPI), deals with the fact that when colliding two hadrons, it is possible<br/><br> for more than one pair of their constituents to interact. The other deals<br/><br> with parton showers, which are used to fill enhanced regions of phase space<br/><br> and give fully exclusive final states. These two components, when part of<br/><br> an event generation framework, help in the simulation of complete high<br/><br> energy collision events.<br/><br> <br/><br> Paper I presents a study of an extension to the MPI model, enhanced<br/><br> screening, where the amount of colour screening in an incoming hadron is<br/><br> increased in those events with a large amount of activity.<br/><br> <br/><br> Paper II presents another extension to the MPI model, rescattering.<br/><br> Commonly, in MPI models, interactions are between pairs of partons which<br/><br> originate from the incoming hadrons. With rescattering, an MPI can instead<br/><br> involve partons which come from previous interactions or shower<br/><br> branchings.<br/><br> <br/><br> Paper III studies the first emission of the parton shower. First, the<br/><br> interface to a next-to-leading generator, POWHEG-hvq, is examined.<br/><br> Second, a dampening of the first shower emission, based on general matrix<br/><br> element arguments is studied.<br/><br> <br/><br> Paper IV again deals with parton showers. Minor changes to the framework<br/><br> are outlined, before a kinematic comparison of the shower is made against<br/><br> 2 to 3 QCD real emission matrix elements. Finally, tunes of the<br/><br> generator are made to both Tevatron and LHC data.<br/><br> <br/><br> Paper V examines an extension to the impact parameter formalism of the MPI<br/><br> model, where the size of an incoming proton is varied depending on the<br/><br> x value of a parton being taken from it.}}, author = {{Corke, Richard}}, isbn = {{978-91-7473-087-6}}, keywords = {{Multiparton Interactions; Parton Showers; Phenomenological Models; QCD Phenomenology}}, language = {{eng}}, publisher = {{Department of Astronomy and Theoretical Physics, Lund University}}, school = {{Lund University}}, title = {{Multiparton Interaction Models and Parton Shower Studies}}, year = {{2011}}, }