Development of comprehensive analysis tools for supernova neutrino detection in multiple experiments

Abstract

A galactic Supernova explosion is a unique neutrino source: detecting the neutrinos from deep inside the star will help us understand both the physics of the core collapse and properties of the neutrinos themselves. If a SN neutrino burst arrived at Earth today or in the near future, it would be detected by a variety of ton to kiloton scale neutrino detectors based on different technologies and target media. By combining the analysis of the explosion in multiple experiments, one could significantly improve the precision of determining the neutrino flux and spectral parameters such as the mean energy and spectral index. In this work an analysis framework was developed in order to be able to fit simultanously the supernova neutrino signals from different detectors. It was shown that by combining three large neutrino detectors such as JUNO, DUNE and IceCube one could achieve percent level precision on the determination of the neutrino spectral parameters. For a canonic supernova at a known distance of 10 kpc, the total energy of the explosion could be measured with 7.1 $\%$ uncertainty. On the example of an 8.8 M$_{\odot}$ supernova, a time-dependent analysis of the signal was carried out. The time evolution of the neutrino spectral parameters was fitted, using an adapted analytical model to describe the time development of mean energy, spectral index and flux. The fit results gave a possibility to measure and estimate some astrophysical parameters of the supernova, such as the accretion time $\tau_a$ = 0.14 $\pm$ 0.01 s. The resulting fit parameters can be used as well to indirectly constrain physical properties of the proto neutron star. Assuming that the distance to the event is known at 2$\%$ level (as for SN1987A), the combination of JUNO, IceCube and DUNE can determine the radii of the flavor-dependent neutrino spheres to 6$\%$ for $\bar{\nu_e}$, 2.2$\%$ for $\nu_e$ and 13$\%$ for $\nu_x$ level accuracy. Moreover the temperatures of the PNS neutrino spheres can be extracted at: 6$\%$ for T$_{\nu_e}$, 1$\%$ for T$_{\bar{\nu_e}}$ and for T$_{\nu_x}$ 7$\%$ level.