Brían Ó Fearraigh, PhD at Nikhef, will defend his thesis Thursday 22 February 2024 at 13.00 at University of Amsterdam.
“Following the Light”
“Billions of neutrinos pass through us every second. These tiny, subatomic particles oscillate between three types, which we call ‘flavours’. Although the phenomenon of neutrino oscillations is now well-understood, and the oscillation parameters have been measured, neutrino experiments today and in the future still aim to measure these parameters more precisely. Neutrinos have a tiny interaction cross section, and so they pass through matter like ourselves with little effect. One experiment which will determine the oscillation parameters with more precision is KM3NeT/ORCA. This infrastructure, currently being built, will instrument a huge volume of seawater in the Mediterranean Sea, capturing the light from the particles resulting from neutrino interactions. KM3NeT/ORCA will also determine the ‘Neutrino Mass Ordering’, the masses of the three neutrino states relative to one another. This outstanding question in particle physics has implications for our fundamental understanding of Nature, and also for how the Universe was formed.
The work in this thesis aims to improve the potential of KM3NeT/ORCA in measuring the neutrino oscillation parameters and determining the Neutrino Mass Ordering. The software used to simulate the atmospheric muons which reach the detector, ~2.5 km below sea level in the Mediterranean, has been ‘tuned’ to KM3NeT data, resulting in an improved description of these muons. This has important implications for simulating the main background in neutrino analyses, and also contributes to the cosmic ray physics the experiment can partake in. A new method of reconstructing the direction and energy of neutrino events is introduced, where the track and shower-like signals induced in the detector are combined and reconstructed as one. Such a reconstruction technique results in an improved estimate of the neutrino energy in the completed KM3NeT/ORCA detector, compared to reconstructing the track and shower signals separately. This novel reconstruction also shows potential for identifying different neutrino interactions types, which is of major benefit to neutrino oscillation analyses. Furthermore, with this track+shower reconstruction, the energy transfer from the neutrino to the hadronic shower can be estimated directly.”
“Following the light – Novel event reconstruction techniques for neutrino oscillation analyses in KM3NeT/ORCA” (pdf)
The PhD defense will take place on Thursday 22 February 2024 at 13.00 at the Agnietenkapel, Oudezijds Voorburgwal 229 – 231, 1012 EZ Amsterdam..
More information and link for the livestream on the website of the UvA.
Supervisor: prof. dr. ir. P.J. de Jong
Co-supervisor: dr. R. Bruijn
contact: Brían Ó Fearraigh