Speaker
Description
Borexino is a 280-ton liquid scintillator detector that took data from May 2007 to October 2021 at Laboratori Nazionali del Gran Sasso in Italy. Thanks to the unprecedented radio-purity of the detector, the real time spectroscopic measurement of solar neutrinos from both the pp chain and CNO fusion cycle of the Sun has been performed. Borexino also reported the first directional measurement of sub-MeV $^7$Be solar neutrinos with Phase-I period (May 2007-May 2010) using a novel technique called Correlated and Integrated Directionality (CID). In this technique, the directional solar neutrino signal is discriminated from the isotropic background events by correlating the well known position of the Sun and the direction of early hits of each event, exploiting the sub-dominant Cherenkov photons emitted at early times. This angular distribution in data is fitted with the signal and background distributions from Borexino Monte Carlo simulation to infer the number of solar neutrinos, after taking into account all the systematics. For the first time, we provide the CNO rate measurement without using an independent constraint on $^{210}$Bi background rate by exploiting CID technique on full Borexino detector live time dataset. This talk will present the complete analysis strategy and latest results on CNO solar neutrinos obtained by using CID technique in Borexino. In addition, we also present the most precise CNO measurement obtained by Borexino using a multivariate technique on Phase-III dataset as used in 2022 analysis, where the novel CID result is now applied as an additional constraint
| Collaboration / Activity | Borexino Collaboration |
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