The JUNO Milano group is active in several branches of the analysis. Regarding possible thesis opportunities, for both bachelor and master students, we propose research topics which include solar neutrinos, neutrino properties as the neutrino mass ordering, and physics beyond the standard model of particle physics.
Solar Neutrino
Solar neutrinos, emitted in fusion processes powering our star, bring us information about the energy-production mechanism in the Sun and about the chemical composition of the solar core. In spite of their copious flux at Earth – about 6.5 billions for each cm2 and for each second – detecting solar neutrinos is experimentally challenging.
JUNO will have a unique potential to perform a realtime measurement of solar neutrinos thanks to its large target mass and its excellent energy resolution, which are prerequisites for reaching unprecedented levels of precision. Oppositely to the antineutrino spectroscopy measurements, the solar neutrino program will be able to deliver important results even in a short data taking.
The Milano group is heavily involved in the activities preliminary to the beginning to the data taking, and to the first analysis to be performed to the solar neutrino data. At present, the main topics available fro bachelor and master thesis are:
- Calibrations for solar neutrino measurements
- Cosmogenic background reduction
- Directionality measurements
- Machine learning methods
Calibrations for solar neutrino measurements: to get prepared to the solar neutrino measurements, a dedicated calibration campaign will be needed, especially focusing on the sub-MeV part of the energy spectrum and for the directionality measurements. We are involved in the following topics:
– definition of calibration sources and deployment plan;
– simulations and analysis of fake Monte Carlo datasets;
– strategies to extract the detector response with the calibration data;
– strategies to extract the detector response with elastic scattering data ($^7$Be shoulder data).
Contacts: Davide Basilico, Barbara Caccianiga, Alessandra Re
Cosmogenic background reduction: cosmogenic isotopes are created by the spallation of cosmic muons on carbon atoms inside the liquid scintillator. In case of a long-lived isotope, we can identify these background events thanks to the spatial and time coincidence of the muon track, the cosmogenic isotope decay and the following neutron capture. The goal is to develop a software technique (Three-Fold coincidence) able to tag the cosmogenic isotope events with high efficiency and high sample purity.
Contacts: Davide Basilico, Barbara Caccianiga, Alessandra Re
Directionality measurements: the novel Correlated and Integrated Directionality (CID) technique allows to separate solar neutrino events from the background ones thanks to the fact that only the former exhibit directional correlation with the Sun’s position, via the detected Cherenkov light. This method can be used to boost the JUNO solar neutrino sensitivity.
Contacts: Davide Basilico, Barbara Caccianiga, Alessandra Re
Machine learning methods: traditionally, the separation of the neutrino signal by the radioactivity background is carried out with the multivariate analysis, which mainly rely on the spectral fit of the reconstructed events. Possible new approaches based on machine learning techniques are becoming increasingly relevant and should be investigated.
Neutrino Mass Ordering
The Milano group is heavily involved in the activities preliminary to the beginning to the data taking, and to the first analysis to be performed on the antineutrino data for the determination of the Neutrino Mass Ordering.
At present, the main topics available for bachelor and master thesis are:
– Towards the first data: analysis optimization and sensitivity;
– Strategy and data analysis of detector calibrations.
The first topic deals with the optimization of the analysis flow so to be ready to work on the real data when to the JUNO detector will acquire. One of the most relevant points is related to the refinement of the selection cuts to maximize the signal over background ratio.
As for the second topic, the calibration of the detector is a crucial and challenging tile for the success of the JUNO rich physics programme. The calibration strategy is based on the periodical deployment of radioactive sources within the liquid scintillator. In view of the calibration data taking, this topic aims to optimize the calibration strategy, and to analyze “fake” simulated datasets to predict the detector energy response parameters with the required precision and accuracy.
Contacts: Davide Basilico, Barbara Caccianiga, Alessandra Re
Physics Beyond the Standard Model
NSI: Non Standard Interactions:
Some theories of physics beyond the Standard Model postulate the existence of neutrino Non-Standard Interactions (NSI) which can have significant impact on neutrino sector. These extensions of the standard model can modify how neutrino interacts with matter and impact the neutrino oscillation phenomenon. The solar sector can be used to probe for this new physics beyond the SM, which can affect the neutrino charged leptons interactions, to which the JUNO experiment is particularly sensitive.
The Milano group is involved in developing an analysis strategy to detect such effects, studying the induced modifications in the electron recoil spectrum observed as a result of neutrino interactions with matter.