ATLAS PhD Students

CLIC PhD study

PHD PROJECTS AND TRAINING

Our postgraduate training is provided within the framework of the Scottish Universities Physics Alliance (SUPA) Graduate School, and provides opportunities to attend various summer schools and physics workshops, as well as to spend time at overseas laboratories such as CERN. The Graduate School provides a structure for progress reports and performance and development review, as well as for student feedback on the quality of supervision. Each student is appointed a first and a second supervisor, so you will be well supported.

‌We put great emphasis on expertise in the field and on generic skills training. Via SUPA, we offer an exceptionally strong and broad training programme in particle physics and related technical skills (such as statistical analysis, programming, and Linux operation). Students choose, with input from their supervisors, which courses to attend depending on their interests in theoretical or experimental physics.

Transferable skills are fostered through the Department and Faculty Graduate Schools. Amongst other activities all Faculty research students attend a residential course on Great Cumbrae Island for teamwork skills. All PPE and PPT students attend the appropriate STFC summer school in Particle Physics at the end of year one, are encouraged to attend STFC entrepreneurship training, and other summer schools and workshops throughout their PhD.

Find out more about our current research projects below.  Other projects may arise on the border of theory and experiment, for example involving beyond-Standard-Model (BSM) interpretations of our ATLAS and LHCb areas of expertise.

ATLAS : HIGGS AND TOP PHYSICS

Beam View of UK Endcap

We expect to offer two or more STFC/Royal Society-funded studentships in this area starting in Sept/Oct 2022.

The Large Hadron Collider (LHC) at CERN is probing the structure of matter at the highest energies achieved in a collider.  By making precision measurements in Higgs, top-quark, and electroweak physics we can probe the structure of the Standard Model and looking for deviations that could indicate new physics. 

Following the discovery of a Higgs-like particle at the LHC in 2012, many measurements remain to be made to verify whether it is a Standard-Model Higgs boson, or something more exotic.  In the ATLAS collaboration, the Glasgow group's efforts are in the channels where a Higgs boson is produced in association with a W or Z boson or in association with a pair of top quarks, and then decays to b-quarks.  The LHC is a top-quark factory, and the ATLAS datasets allow unprecedented measurements of this, the heaviest of the known elementary particles.

We also study the behaviour of the strong nuclear force, Quantum Chromodynamics, which is a key factor in all LHC analyses and presents many theoretical difficulties that can only be resolved by confronting predictions with increasingly challenging experimental measurements. Our QCD analysis efforts are centred on understanding how heavy c and b quarks are produced, and the structure of QCD particle jets: these aspects of QCD are central to our programme of Higgs and top-quark measurements.

The successful candidate will undertake exciting research within a strong Glasgow ATLAS group.  They will be expected to travel for short trips to CERN, Geneva and will have the opportunity to spend an extended period at CERN.

Potential projects for 2022 are listed below:

ATLAS Project 1: "Exploring the boundaries of quantum information at the LHC"

Supervisor:  Dr Jay Howarth  (James.Howarth@glasgow.ac.uk)

Quantum entanglement (or "spooky action at a distance" as Einstein called it) is one of the most spectacular features of quantum mechanics.  It has been studied in many contexts but it has never been studied at the energy scales available at the LHC nor has it been observed in fundamental fermions not bound in atomic states.  In this PhD project, we will be measuring, for the first time, quantum entanglement in the qubit systems that exist in top-quark pair events and qutrit systems that exist in Higgs boson decays using ATLAS Run2 and Run3 data.  This project is at the forefront of LHC physics and is a unique and unexplored bridge between the fields of particle physics and quantum information.  It would ideally suit students wishing to push the boundaries and develop connections between these two fields.

 

ATLAS Project 2: "Boosted Higgs and new physics"

Supervisor: Prof Aidan Robson  (aidan.robson@glasgow.ac.uk)

Precise characterisation of the Higgs boson is a top priority in collider physics, addressing the key question of what the basic constituents of matter are and how they interact.  In the Standard Model the most frequent decay of the Higgs boson is to b-quarks, but owing to the large backgrounds this was only recently observed, in 2018.  In this PhD project we will measure the Higgs boson, produced in association with a W or Z boson and decaying to b-quarks, using the first LHC Run-3 data.  We will focus particularly on the 'boosted' regime where the Higgs boson has high momentum and needs special reconstruction techniques; this is also the regjon of the parameter space most sensitive to new physics, and so this project will give scope for working at the intersection of precision measurement and Beyond Standard Model (BSM) interpretation.

 

ATLAS Project 3: "When protons survive!: searching for elastic top-quark events at the LHC"

Supervisor: Dr Jay Howarth  (James.Howarth@glasgow.ac.uk)

The LHC collides over a billion protons per second, producing spectacular events from the collision energy and energetic remnants of the colliding protons.  However, in rare cases, one or both of these protons can survive the collision and go on to be detected by dedicated forward detectors situated hundreds of metres down the beampipe.  In even rarer cases, these "elastic" protons can even produce particles as massive as top quarks.  In this PhD project, we will be searching for these rare events and looking for signs that they are produced more frequently than expected, which would point to signs of new physics in their production.  This project has scope to make a large impact on the burgeoning field of forward physics at ATLAS and is best suited to students who are willing to leave textbook world and to explore physics where the problems are truly unique, the work is rewarding, and the answers are unknown (and we hope, unexpected!).

LHCB: LEPTON FLAVOUR VIOLATION AND TRACKER UPGRADE

We expect to offer an STFC-funded studentship in this area starting in Sept/Oct 2022.

The main focus of the LHCb experiment, located at the Large Hadron Collider at CERN, is the study of CP asymmetry, believed to be one of the causes of the matter-antimatter asymmetry of the present universe. The origin of CP violation in the Standard Model is through the so-called CKM matrix that describes the level of quantum mechanical mixing amongst quarks. Because the CKM matrix contains a complex term, this causes a small time-dependent asymmetry between the decay of particles and their anti-matter counterparts. This effect will be particularly strong in the decay of B and anti-B mesons (particles that have a B or “bottom” quark).

The Glasgow group has worked on a range of analyses at LHCb, including:

Measuring the unitarity angle gamma, which is particularly poorly known:  one of the main aims of the LHCb experiment is to measure this angle gamma in a variety of decay channels, and search for New Physics by comparing channels that are sensitive to new CP violating mechanisms with those that mainly measure the Standard Model gamma.  A leading candidate for such a measurement comes from the comparison of time dependent asymmetries in the decays of channels Bd->D-pi+ and Bs->Ds-K+; this research culminates in a measurement of the Standard Model value of gamma with unprecedented accuracy, which can be compared with a measurement of gamma sensitive to New Physics.  This programme of research also includes unbiased measurements of the lifetime of the B mesons, resulting in the world’s best measurement of the Bd and Bs lifetimes.

Looking for new physics effects in rare decays; for example the angular distribution of the particles produced in the decay of the B meson to a K* meson plus two muons.

PhD students in this area work within the Glasgow LHCb group of seven research staff and four PhD students.  Activities include the analysis of data, and running and operating the experiment.  Students are expected to travel to CERN in Geneva regularly, and to spend a period of around one year based at CERN.

Potential projects for 2022 are listed below:

LHCb Project 1:  “Lepton universality tests and new physics, and design of the future LHCb tracking system”

Supervisor: Dr Lucia Grillo  (lucia.grillo@cern.ch)

Recent measurements have hinted at the breakdown of lepton universality, a central principle of the Standard Model of particle physics.  Angular analyses of b-hadron decays to a charm hadron, a neutrino and either a muon or a tau lepton at LHCb, have the sensitivity to establish the effect.  In this PhD project we will exploit these semileptonic b-hadron decays to test lepton universality and investigate the nature of potential New Physics processes.  Excellent track reconstruction capabilities are essential for the physics programme of LHCb and we will also work on the design of the tracking system for future upgrades:  design of new detectors exploiting emergent technologies and optimisation of track reconstruction strategies will enable LHCb to meet the performance requirements in the increasingly challenging data-taking conditions.

CDT IN 'DATA-INTENSIVE SCIENCE'

In addition, for Sept/Oct 2022 we may have the possibility to recruit a PhD student as part of the ScotDIST centre for doctoral training (https://www.scotdist.ac.uk/) to work on "data-intensive" challenges in particle physics.  The main focus of these studentships is on novel applications of machine-learning, or other computational statistics methods, to physics challenges from data-analysis to event simulation.  The ScotDIST PhD positions are for 4 years, including 6 months total of industrial placement in data science, and involve additional training and coursework in scientific computing.

Supervisor: Dr Andy Buckley  (andy.buckley@glasgow.ac.uk)

T2K: NEUTRINO PHYSICS

We do not expect to offer an STFC-funded studentship in this area starting in Sept/Oct 2022, but would be glad to consider candidates for scholarship funding.

Following longstanding involvement in neutrino physics, the Glasgow group has recently joined the T2K experiment and a new academic in this area joined the group in February 2019. We are working on the T2K long-baseline neutrino oscillation experiment, in which a predominantly muon-neutrino beam, generated at the J-PARC accelerator facility in Tokai, changes flavour and appears as electron-neutrinos at the Super-Kamiokande water Cherenkov detector in the Kamioka mine, at a distance of 300 km. This allows the study of neutrino interactions in the near detector facility at T2K and use of these data to contribute to the analysis of neutrino and antineutrino oscillations. The ultimate goal of the experiment is to determine differences between the rate of appearance of electron-neutrinos and electron-antineutrinos, which could show the first evidence for CP violation in neutrinos. We also expect to be involved in the development of new electronic boards for the T2K near-detector upgrade, or for the upgrade of the Super-Kamiokande experiment, called Hyper-Kamiokande.

NA62: RARE KAON DECAYS

We do not expect to offer an STFC-funded studentship in this area starting in Sept/Oct 2022, but would be glad to consider candidates for scholarship funding.

The Glasgow group has been a central part of the analysis of the pre-2018 data, working on both the normalisation channel and the upstream backgrounds in the signal channel.  The LHC "Long Shutdown 3" has provided a window of opportunity to develop more modern analysis techniques using Machine Learning to improve upon previous cut-based analysis for the data taken from 2021 onwards.