Peter Ballett

Institute for Particle Physics Phenomenology
Department of Physics

University of Durham
Science Laboratories
South Road

I'm Peter Ballett and I work as a postdoctoral researcher in Particle Physics at Durham University. I completed my PhD at Durham in 2013 under the supervision of Prof. S. Pascoli.

My research interests broadly lie in particle physics phenomenology and neutrino physics, with connections to flavour physics and model building. I have a particular interest in the phenomenology of neutrino oscillation experiments and their potential for discovering CP violation in neutrino mixing, and more generally for investigating the new physics associated with neutrino mass and (optimistically!) leptonic flavour. However, I find that I am interested in most topics in the neutrino sector, adjacent areas and beyond; so please get in touch if you want to discuss anything!

Discrete Family Symmetries

I am interested in how medium-term oscillation experiments will be able to constrain models with discrete leptonic family symmetries. Models of this type have been very successful at producing phenomenologically viable mixing patterns but, as our knowledge of the PMNS matrix increases, will soon be subject to considerable experimental constraints. Understanding which parameter correlations can be associated with different theoretical constructions and how well different proposed facilities can observe such signatures allows us to assess the viablility of specific BSM ideas. This work also represents a concrete application of precision in neutrino flavour physics.

My colleagues and I have focused on deriving and systematically exploring three types of correlation: atmospheric and solar sum rules and a class of solar mixing predictions. Importantly, these types of correlation can be related to concrete model-building ideas which lead to PMNS matrices constrained by residual symmetries, with possible corrections coming from symmetry breaking in the charged-lepton sector. You can find more details on this work in the following preprints: arXiv:1308.4313, arXiv:1406.0308 and arXiv:1410.7573.

I have also recently been working more holistically, focusing on the predictions of a single symmetry group: A5 with a generalised form of CP invariance. My colleagues and I have then derived all possible parameter correlations arising in this scenario which could satisfy prior observations, and have studied the potential to constrain these patterns using upcoming and future oscillation experiments. We stress the interplay between different predictions which greatly increases the testability of these models, and which can be lost in more generic studies. For more details, see arXiv:1503.07543.

Neutrino Oscillations

I was a member of the LAGUNA-LBNO collaboration, performing simulations to understand the physics potential of LBNO and studying questions of precision and new physics. Part of this work is presented in a paper on the MH and CPV reach of the LBNO design, available in arXiv:1312.6520. This work was then extended the following year by further optimising the beam, and studying a novel experimental arrangement involving a second neutrino beam directed at the same detector, for details see arXiv:1412.0593 and arXiv:1412.0804.

In the past, I have also studied longer-term proposals, for example the Low-Energy Neutrino Factory (LENF). In arXiv:1201.6299, Prof. Pascoli and I worked to understand the optimal LENF design and to understand the behaviour of this facility as it interpolates between low- and high-energy variants. We have also made an exhaustive (exhausting?) set of plots from this study available for download.

Some of our work on the LENF has been included in the International Design Study for the Neutrino Factory (IDS-NF) as part of the Interim Design Report (IDR). Details of this project and the IDR itself can be found here.

Conference presentations & seminars

I have presented my work at the following events: