Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30$M_{\odot}$ for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

First experimental proof of CNO fusion cycle in Sun with the Borexino Experiment

Borexino, an ultra-pure liquid scintillator detector located at the Laboratori Nazionali del Gran Sasso in Italy, has detected solar neutrinos from the CNO fusion cycle for the first time in history. The CNO cycle is predicted to be the dominant energy production process in massive stars, while it is a secondary mechanism for the solar energy production. Its small associated neutrino flux, as well as the similarity of the spectral shapes of electrons scattered off CNO and pep solar neutrinos and electrons from the decays of 210Bi background, make measurement of CNO solar neutrinos very challenging. The proof of the existence of CNO fusion process in Nature has been made possible by carrying out several campaigns of purification of Borexino liquid scintillator and in 2016, thermal stabilization of the detector. This talk, on the behalf of the Borexino collaboration, will present the overview of the challenges along with their solutions adopted to extract the CNO solar neutrino signal with the rejection of the null hypothesis with greater than 5sigma significance at 99% C.L as well as the implications of this result for solar physics

Understanding the systematic effects for the directional measurement of Be-7 solar neutrinos with Borexino

Borexino, located at the Laboratori Nazionali del Gran Sasso in Italy, is a liquid scintillator detector that measures solar neutrinos via their forward elastic scattering off electrons . The scintillation process of detection makes it impossible to distinguish electrons scattered by neutrinos from the electrons emitted from the decays of radioactive backgrounds. Due to the unprecedented radio-purity achieved by the Borexino detector, the real time spectroscopic detection of solar neutrinos from both the pp chain and CNO fusion cycle of the Sun has been performed. With the newly presented analysis, it is now possible for the first time, to detect solar neutrinos using the few Cherenkov photons emitted at early times, in the direction of scattered electrons with an energy threshold of 0.16 MeV in the liquid scintillator. The angle which correlates the direction of the Sun and the direction of the emitted Cherenkov photons is a key parameter to extract the Be7 neutrino signal from data. This poster will describe the strategy used in the evaluation of various systematic effects including the geometric conditions of the detector and the data selection cuts that can influence the shape of the directional angle distribution for backgrounds, which is crucial to disentangle the directional Be-7 solar neutrino signal from the isotropic background in data

JUNO's sensitivity to 7Be, pep and CNO solar neutrinos

JUNO Experiment is a 20 kt multipurpose liquid scintillator detector located in China, with planned completion of construction in 2023. Its main goal is the Neutrino Mass Ordering determination, exploiting its large target mass and excellent energy resolution of 3% at 1 MeV. Due to its unique properties, JUNO will have a large potential for real-time solar neutrino measurement. A sensitivity study is performed by considering all possible sources of backgrounds including their various concentration levels and a full simulation of the detector response with the usage of reconstructed variables. Results have shown that $^7$Be, pep and CNO solar neutrinos will be measured with an uncertainty highly competitive with respect to the current state-of-the-art in the solar neutrino field obtained by Borexino after a few years of data taking. Furthermore, JUNO has the potential to measure individually for the first time the rate of the two main components of the CNO neutrino flux, $^{13}$N and $^{16}$O solar neutrinos, given that the backgrounds are kept under control. This poster will summarize the strategy used for the estimation of the JUNO sensitivity to $^7$Be, $pep$, and CNO solar neutrinos above the 0.45 MeV threshold and the final results