Final Report Summary - NEUTRINOSNOVA (Searching for the remaining unknown neutrino oscillation parameters using the NOvA long baseline experiment.) Research objectives:The overall aim of this fellowship was to develop and exploit the unique capabilities of the NOvA experiment (https://www-nova.fnal.gov/) to study the fundamental physics underlying the phenomena of neutrino oscillations. Specifically:• The discovery of electron anti-neutrino appearance in a muon anti-neutrino beam.• To determine the neutrino mass hierarchy.• To search for CP violation in the lepton sector.Obtaining these aims in a large collaborative experiment such as NOvA involves many different tasks that need to be fulfilled. Therefore it was proposed that this project undertake a multi-disciplinary approach focusing on key contributions to areas central to achieving the overall project aims. The specific objectives of this project were:• To take a leading role in the development of the data-driven trigger (DDT) system, the system that governs the collection of events seen within NOvA based on their specific topology.• To develop cutting edge reconstruction techniques that will enable NOvA to consistently and accurately identify the physical processes responsible for each neutrino event and therefore distinguish signal events from background ones.It was also the intention of the fellow to exploit NOvA’s unique “totally active” design to search for the signatures of galactic supernovae, the observation of which would provide a wealth of insight both into the nature of these rare events and into the character of the neutrinos themselves. Further a small fraction of the fellow’s time would be spent on development of future neutrino experiments and on understanding the nature and direction of the field as a whole.Work performed:During the course of this fellowship the fellow worked on a diverse series of projects within the NOvA collaboration. The scope of the work adapted to the changing run plan of the NOvA experiment and to take advantage of opportunities to maximise the fellow’s impact on the collaboration and experiment. The main focus of the fellow’s work can be sub-divided into three main periods:DDT (04/2014 - 07/2014): the fellow developed and deployed a contained muon neutrino trigger. He also developed a minimum bias trigger for the near detector that was later used to collect all calibration data used in the publications related to the first NOvA analysis. The fellow played a key role in commissioning the DDT, culminated in a poster presentation at the Neutrino 2014 conference.Production convener (07/2014 - 06/2015): The fellow was appointed team leader of the 20 researchers responsible for processing the Petabytes of data produced by the NOvA experiment, as well the Monte Carlo simulations used to interpret the data. This included responsible for the large cloud computing resources and data management systems needed for the experiment.Calibration convener (10/2015 - 04/2016): The fellow was appointed team leader of ten researchers and academics responsible for the calibration and understanding of the detector response. This included planning and directing the focus of the group and ensuring the group’s activities align well with the experiment’s aims and facilitate communication with the wider collaboration.Throughout the course of the fellowship a number of additional tasks were completed by the fellow:Supernova simulation and triggering: pioneered the first simulation of supernova neutrino events in the NOvA detector. Developed the first reconstruction techniques to begin to identify these.Muon neutrino disappearance analysis: numerous contributions including validating and cross checking the first analysis results and defining and implementing measures of key systematic uncertainties.Calibration systematic uncertainties: measured key sources of systematic uncertainty forming a dominant part of the uncertainty on the measurements published in both the NOvA first analysis papers.Institute board representative: Elected representative of all students and non-staff researchers within the NOvA collaboration.DUNE: Played a central role in the implementation of the triggering and data acquisition framework used in the prototype DUNE detector (http://www.dunescience.org/).The main results of the fellow’s work are in contributions to two papers published on the first NOvA results, one in PRD rapid communications and one in PRL. These results, while not yet world leading, represent a competitive measurement of the fundamental parameters the govern the physics of neutrino oscillations. The NOvA experiment is now well placed to collect more data to further probe these mysteries over the coming years and to shed light on the nature of the neutrino mass hierarchy and CP violation.
