2022
Many congratulations to Samuel Holt,Arnau Brossa Gonzalo and Benjamin Cooke, for their success in the 2022 PhD Thesis Prize competition!
SEM Faculty Thesis Prize-Sam Holt
Sam worked on exotic magnetic states known as skyrmions. He writes "I started at the University of Warwick in 2013 where I completed my undergraduate degree and continued at Warwick for my PhD under the supervision of Geetha Balakrishnan. My PhD research was undertaken as part of the UK Skyrmion project, a collaboration between the universities of Warwick, Oxford, Cambridge, Durham, and Southampton which investigates the physics of topological magnetic textures known as magnetic skyrmions. These skyrmion systems have been of great interest since their recent discovery in 2009 due to the interesting physics they present and their potential uses in spintronic devices. My thesis focused on studying skyrmions in Néel systems, Bloch skyrmions in confined geometries, and creating Python software to simulate the results of various experimental techniques on arbitrary magnetic states. I have since been working as a research fellow at the University of Southampton specialising in computational magnetism."
Congratulations on the Faculty thesis prize, Sam!
Springer Thesis Prize-Arnau Brossa Gonzalo
Arnau Brossa Gonzalo was awarded the Springer Thesis Prize, for his doctoral thesis "First observation of B0→Dbar*(2007)0K+π− and B0s→Dbar*(2007)0K−π+ decays in LHCb". Arnau explains:"The Standard Model of particle physics is extremely successful at describing matter interaction at the most fundamental level. However, it is not perfect and while it provides several predictions up to an impressive level of precision it fails to answer some questions such as the difference between matter and antimatter in the early stages of the universe, which predictions are in direct disagreement with cosmic background radiation observations.
My work is yet another step towards answering this question, focusing on the search of B hadron decays to a D* meson, a Kaon and a Pion. These decays exhibit CP-violating properties, i.e. this decay behaves slightly differently than the conjugate anti-B hadron decay. This makes its understanding crucial for the finding of possible discrepancies with respect to the Standard Model predictions. As these decays are extremely rare and can only occur at very high energies, my work is based on the data recorded by the LHCb experiment during the years 2016 to 2018. The data sample consists in proton proton collisions at energies at the TeV scale. These collisions generate a very rich hadronic environment with a small probability for these decays to occur among hundreds of other processes.
In order to be able to measure these processes, we require a detector capable of tracking and identifying all the different particles involved in the decay. Since the probability for these decays to occur, and more importantly, to be detected is so small, a high number of events (of the order of millions!) is required. From all these events only the events which include the decay under study are selected. Using that process we can measure not only the probabilities for the B-hadron and anti B-hadron decays to happen but also to measure the momentum distribution of the final state particles which is crucial for the complete understanding of this and similar CP-violating processes."
Well done to Arnau on his prize!
Winton Thesis Prize-Ben Cooke
Ben's studies were on extra-solar planets. He explains "My PhD focussed on monotransiting exoplanets – these are planets which orbit stars other than the sun that are only seen to transit once during our observations of them. The majority of well characterised exoplanets have short orbits, allowing us to see them transit multiple times and making it easier to constrain their periods. Those on longer orbits, planets more similar to our own, are more likely to be monotransits and their periods are harder to constrain. In my thesis I predict the abundance of these type of signals in the data from a current transit mission, TESS (Transiting Exoplanet Survey satellite), as well as simulate the optimal way to follow them up to better characterise them with the minimum expenditure of telescope time. I found that, for exoplanets with periods greater than 30 days, monotransits well outnumber multitransits and are thus vital to better explore this region of parameter space. The work in this thesis has helped influence the direction of NGTS (Next-Generation Transit Survey) and led to the discovery and characterisation of some of the first monotransiting exoplanet systems from the TESS mission.
The figure shows the predicted distribution of multi and monotransiting systems found by TESS, multitransit systems are in red with monotransit systems in blue. It is clear that to properly explore the parameter space for orbits over 30 days one must effectively utilise monotransits."
Many congratulations to Ben on the fantastic work.