Speaker
Description
Borexino, located at the underground Laboratori Nazionali del Gran Sasso in Italy, was a large liquid scintillator detector designed for real-time detection of low-energy solar neutrinos. During more than ten years of data taking, it has measured all the neutrino fluxes produced in the proton-proton chain, the primary fusion process responsible for 99 % of solar energy, as well as from the sub-dominant Carbon-Nitrogen-Oxygen (CNO) fusion cycle.
The determination of the CNO signal is performed through a multivariate spectral analysis, leveraging the excellent radiopurity achieved in Borexino. The main challenge of this measurement lies in independently determining the $^{210}$Bi contamination, essential for constraining its rate in the multivariate fit to break the anti-correlation with CNO neutrinos.
Recently, Borexino has introduced an innovative technique, called "Correlated and Integrated Directionality" (CID), based on the features of fast directional Cherenkov light. This method exploits the correlation between the known position of the Sun and the direction of reconstructed photons. Specifically, Cherenkov PMT hits generated by solar neutrino interactions correlate with the position of the Sun, while both isotropic scintillation light and hits produced by background events do not. Borexino has provided the proof of principle of this new method through the first directional measurement of sub-MeV $^7$Be neutrinos.
This poster presents the first observation of CNO solar neutrinos utilizing the CID technique. Unlike the spectral analysis, this measurement is performed without any prior information regarding the $^{210}$Bi contamination employing all Borexino available data. Furthermore, this result is combined with an improved two-dimensional multivariate analysis of the Phase III dataset, leading to the
final and most precise Borexino CNO measurement.
| Poster prize | Yes |
|---|---|
| Given name | Luca |
| Surname | Pelicci |
| First affiliation | Forschungszentrum Jülich |
| Second affiliation | RWTH Aachen University |
| Institutional email | lucapelicci@gmail.com |
| Gender | Male |
| Collaboration (if any) | Borexino |
