4th Year Projects in 2016

From SydneyHEPWiki
Jump to: navigation, search

Below is a list of the 4th year projects offered for Semester 1, 2016. These are representative of the sort of projects we can offer - we may alter some of these closer to the time or indeed add new possibilities.

Simultaneous measurements of Standard Model cross-sections at the Large Hadron Collider

Supervisors: A/Prof Kevin Varvell,Dr Kevin Finelli,Dr Jin Wang
Contact: A/Prof Kevin Varvell,
Room: 344
Email: kevin.varvell AT sydney.edu.au
Phone: (02) 9351 2539

The Large Hadron Collider is designed to produce exotic particles such as the Higgs boson, top quark, and W and Z bosons by colliding protons together and using gigantic detectors like ATLAS to examine the debris. By fitting data collected by ATLAS to predictions made by the Standard Model, the model which describes all fundamental interactions of elementary particles, we can simultaneously study the production mechanisms of several rare processes. This simultaneous measurement allows us to perform a global test of the Standard Model which has the potential to reveal new physical processes beyond the Standard Model, and will attempt to resolve or confirm discrepancies seen in other LHC measurements. The student will have the opportunity to collaborate with scientists based at CERN and will be involved in statistical analysis of LHC data. This work would be suitable both for standalone honours projects and for projects leading into subsequent PhD research.


Data acquisition for an upgraded ATLAS detector at a High Luminosity Large Hadron Collider

Supervisors: A/Prof Kevin Varvell
Contact: A/Prof Kevin Varvell,
Room: 344
Email: kevin.varvell AT sydney.edu.au
Phone: (02) 9351 2539

In the future the Large Hadron Collider at CERN will be upgraded to high luminosity running (the so-called HL-LHC) and this will require the giant detectors such as ATLAS to undergo their own upgrades in order to be able to collect data at significantly higher rates. Planning for this is already underway, and in this project a local test-stand for studying fast read-out possibilities for the new ATLAS inner tracker (ITK) will be developed.


The testing of the Standard Model through precision measurement - Precision Higgs measurements

Supervisors: Dr Anthony Morley, A/Prof Kevin Varvell
Contact: Dr Anthony Morley,
Room: (based at CERN in 2015)
Email: anthony.morley AT sydney.edu.au
Phone: +41 22 76 77975

The Higgs Boson discovery, while interesting and extremely exciting, was very much expected physics. The ATLAS detector has, so far, found no traces of truly new physics: supersymmetric particles, extra dimensions, etc. At present there is no strong evidence for any of the new models and at the same time a large number of these models cannot be ruled out. Studying the newly discovered Higgs Boson in great detail is one potential avenue to finding new physics. In this project we will study ways to enhance the ability of the ATLAS detector to measure the properties of the Higgs boson.


Design and optimisation of the next-generation tracking algorithms at the LHC

Supervisors: Dr Anthony Morley, A/Prof Kevin Varvell
Contact: Dr Anthony Morley,
Room: (based at CERN in 2015)
Email: anthony.morley AT sydney.edu.au
Phone: +41 22 76 77975

The LHC has turned on again is running at 13 TeV and to the expedite the search for new phenomenon the LHC will endeavour to collide more protons simultaneous than it has ever done before. All of these simultaneous collisions introduces a number of experimental challenges when trying to identify what has occurred in each of these collisions. This project will address one these challenges specifically the accuracy and speed in which we reconstruct charge particles in these collisions. This project will expose the student to machine learning, optimisation and pattern recognition techniques.


This work contribute design of the planned upgrades to the ATLAS tracking detector that will be replaced in 2022.


Exotic particles from Initial-State Radiation in the Belle II experiment

Supervisors: A/Prof Kevin Varvell
Contact: A/Prof Kevin Varvell,
Room: 344
Email: kevin.varvell AT sydney.edu.au
Phone: (02) 9351 2539

The Belle II experiment at the SuperKEKB electron-positron collider in Japan, currently being constructed, will primarily aim to study rare decays of B mesons. However it will also be able to search for new exotic states containing quarks and gluons, using a technique known as Initial State Radiation (ISR), which effectively enables the energy at which the electron and positron collide to be tuned. In this project a Monte Carlo study of the ISR process at Belle II will enable us to gauge the potential of this technique for extending our understanding of how quarks and gluons bind to form hadronic matter.


Searching for charged exotic mesons at ATLAS

Supervisor: Dr Bruce Yabsley
Contact: Dr Bruce Yabsley
Room: 363
Email: bruce.yabsley AT sydney.edu.au
Phone: (02) 9351 6808

Many so-called exotic mesons have been seen over the last twelve years: particles that do not have the quark-antiquark structure of the established mesons such as the pions, kaons, D-mesons, etc. Since 2007 candidates for charged exotic states have also been seen, with possible explanations including tetraquark structures, and pairs of mesons bound together in deuteron-like "molecules". These states have been seen at electron-positron colliders, but they may also be produced at hadron-hadron colliders: the neutral exotic meson X(3872) is produced in both pp and p pbar interactions.

In this project, you will design a search for charged exotics at ATLAS, an experiment at CERN's Large Hadron Collider (LHC). ATLAS' neutral exotic search was performed in Sydney, and will serve as a working model. If the search proves feasible, the project could form the basis for subsequent doctoral research.


Antiprotons and exotic mesons at Belle II

Supervisor: Dr Bruce Yabsley
Contact: Dr Bruce Yabsley
Room: 363
Email: bruce.yabsley AT sydney.edu.au
Phone: (02) 9351 6808

The Belle II experiment, under construction in Japan, has a rich physics program including precision measurement of CP violation, searches for rare new physics processes, and studies of exotic mesons. Belle I , which ran from 1999 to 2010, dominated the study of exotic quarkonium-like mesons for many years, beginning with the discovery of the first such state, the X(3872). Belle II is expected to take a hundred times the data of Belle I, as well as improving the quality of measurements.

One of those improvements is a joint Sydney-Novosibirsk project to calibrate the Belle II response to anti-protons, opening the door to many new physics measurements. An example is the rare decay of the X(3872) to a proton and an anti-proton, which is theoretically and experimentally important, but has not yet been observed. In this project you will develop and test the methods for such a search at Belle II.


Measuring exotic meson lineshapes with multidimensional fitting at Belle II

Supervisor: Dr Bruce Yabsley
Contact: Dr Bruce Yabsley
Room: 363
Email: bruce.yabsley AT sydney.edu.au
Phone: (02) 9351 6808

The 2003 discovery of the X(3872), a charmonium-like particle which does not have the normal quark-antiquark structure of the classic mesons, has led to a revolution in meson spectroscopy. But the structure of the X(3872) itself is still imperfectly known. A high-resolution measurement of the lineshape of certain X(3872) decays would be decisive, but no current experiment has the required precision.

An X(3872) analysis at the Belle experiment in 2011 found that the use of multidimensional fits to the data could resolve decay widths narrower than the nominal resolution of the detector. This intriguing result has not been further studied, but could be important for the measurement of decay widths and lineshapes at the successor experiment, Belle II. In this project, you will investigate and understand this effect, and assess its potential for measurements at Belle II.


Nonlocal CPT violation in neutral meson systems

Supervisor: Dr Archil Kobakhidze, Dr Bruce Yabsley
Contact: Dr Archil Kobakhidze
Room: 367
Email: archil.kobakhidze AT sydney.edu.au
Phone: (02) 9351 5349

The Standard Model of particle physics is CPT-symmetric: processes related by charge conjugation (C), parity (P), and time reversal (T) should behave identically. (One consequence is the identical masses of the proton and anti-proton.) There are strong theoretical arguments that the CPT symmetry should hold, but various proposals for "new physics" at high energies can produce CPT violation. The experimental effects can be striking, including vacuum birefringence and other violations of Lorentz symmetry.

There is a recent theoretical proposal that nonlocal effects could produce CPT violation while preserving Lorentz covariance. The experimental implications of this have been studied for neutrinos, but not for other physical systems. In this project, you will study the CPT symmetry within the framework of quantum field theory, learn the rich set of experimental results on the mixing of neutral mesons (such as the K0, B0, and their antiparticles), and determine the implications of nonlocal CPT violation for neutral mesons.


Black Hole as a Quantum Coherent State of Gravitons

Supervisor: Dr Archil Kobakhidze
Contact: Dr Archil Kobakhidze
Room: 367
Email: archil.kobakhidze AT sydney.edu.au
Phone: (02) 9351 5349

In this project we attempt to quantize classical Schwarzschild black holes by means of a coherent state of gravitons.


Interacting Dark Matter

Supervisor: Dr Michael Schmidt
Contact: Dr Michael Schmidt
Room: 368
Email: michael.schmidt AT sydney.edu.au
Phone: (02) 9351 3810

The mystery of the missing mass in the Universe is still unsolved. Particle physics provides a simple and elegant solution in terms of a cosmologically stable particle, denoted as dark matter, which naturally occurs in extensions of the Standard Model (SM) of particle physics. The most popular DM candidate is a weakly interacting massive particle (WIMP), which is cold and interacts only weakly with SM particles and itself. Seeing the rich nature of the SM one might however question that 80% of the mass in the Universe is described by one particle species only. Moreover there are some hints that the simple picture might be oversimplified. In this Honours project you will study the phenomenology of dark matter interactions in a simple extension of the SM.


Common Origin of Neutrino Mass and Dark Matter

Supervisor: Dr Michael Schmidt
Contact: Dr Michael Schmidt
Room: 368
Email: michael.schmidt AT sydney.edu.au
Phone: (02) 9351 3810

Neutrinos are massless in the Standard Model (SM) of particle physics. However the observation of neutrino oscillations showed that at least two neutrinos are massive. The absolute mass scale is still unknown, but constrained by cosmology, beta decay and neutrino-less double beta decay experiments. Neutrinos are much lighter than any of the other SM fermions. An attractive explanation for their smallness is that neutrinos only obtain their mass as a quantum effect. These models often feature unbroken symmetries, which lead to a cosmologically stable particle and thus a dark matter candidate. You will study the phenomenology of one model of neutrino mass with a dark matter candidate.


Mono-stop events in natural MSSM

Supervisors: Dr Lei Wu, Dr Archil Kobakhidze
Contact: Dr Lei Wu
Room: 364
Email: lei.wu AT sydney.edu.au
Phone: (02) 9351 2712

Supersymmetry is a unique nontrivial extension of relativistic invariance, which is considered as a leading candidate for a new particle physics model. It provides a framework for a light Higgs boson without invoking unnatural fine-tuning of theory parameters. However, the recent discovery of a Standard Model (SM) Higgs-like particle with a mass around 125 GeV, in conjunction with non-observation of supersymmetric particles, has largely excluded the most studied parameter range within the minimal supersymmetric Standard Model (MSSM), for which the naturalness criterion is satisfied. Therefore, it is imperative to investigate the less explored space of parameters, where the theory maintains naturalness, and look for alternative strategies for verifying such natural SUSY models at the Large Hadron Collider (LHC). In this project, we investigate the possibility of monostop signals induced by the compressed spectrum at the 14 TeV high-luminosity LHC(HL-LHC) as a probe of natural SUSY.


New Physics in the Higgs self coupling at future colliders

Supervisors: Dr Lei Wu,Dr Archil Kobakhidze
Contact: Dr Lei Wu
Room: 364
Email: lei.wu AT sydney.edu.au
Phone: (02) 9351 2712

Measuring the Higgs-self coupling is one of the most important tasks for experiments at the Large Hadron Collider (LHC) as well as at future colliders, such as the International Linear Collider (ILC). In the renormalizable Lagrangian of the Standard Model (SM), only the quartic Higgs coupling is allowed by the electroweak gauge symmetry. The measurement of the Higgs self-coupling is essential to reconstruct the Higgs potential and understand the electroweak symmetry-breaking mechanism. In some extensions of the SM, the self-coupling can be significantly distorted by quantum corrections from yet undiscovered particles and, thus, is sensitive to the new physics. In addition, large deviations in the Higgs self-coupling may have significant cosmological consequences, driving strongly first-order electroweak phase transitions in the early universe.

In this project, we investigate the observability of new physics in the Higgs self-coupling in future collider experiments, such as those at the high luminosity LHC and ILC.