THE BOREXINO IMPACT IN THE GLOBAL ANALYSIS OF NEUTRINO DATA

This thesis reports on work I carried out within the Borexino collaboration in the past three years. The main purpose of my work was to collect, analyze and understand the implications of the Borexino results in neutrino oscillation physics and in solar physics. We first studied the impact of each single piece of information coming from the Borexino experiment in determining the allowed regions of the (tan(theta_12), D m2_21) space of parameters. Concerning the neutrino oscillations field, we combined the Borexino results with those obtained by the other solar experiment (Gallex/GNO, SAGE, Homestake, Super Kamiokande, SNO) and we showed that, thanks to the Borexino inclusion, the LOW region of MSW regime is, for the first time, strongly disfavored by solar neutrino data alone. For what concerns solar Physics, in order to study the Standard Solar Model parameters and to look deeper into the low/high metallicity controversy, we left Phi(7Be) and Phi(8B) as free parameters of the fit. Under the luminosity constraint, we showed how, at present, solar neutrino data cannot discriminate between the low/high metallicity hypothesis in the standard solar model.