e-{\mu} Discrimination at High Energy in the JUNO Detector

Cosmic Ray and neutrino oscillation physics can be studied by using atmospheric neutrinos. JUNO (Jiangmen Underground Neutrino Observatory) is a large liquid scintillator detector with low energy detection threshold and excellent energy resolution. The detector performances allow the atmospheric neutrino oscillation measurements. In this work, a discrimination algorithm for different reaction channels of neutrino-nucleon interactions in the JUNO liquid scintillator, in the GeV/sub-GeV energy region, is presented. The atmospheric neutrino flux is taken as reference, considering $\overset{(-)}{\nu_\mu}$ and $\overset{(-)}{\nu_e}$. The different temporal behaviour of the classes of events have been exploited to build a time profile-based discrimination algorithm. The results show a good selection power for $\overset{(-)}{\nu_e}$ CC events, while the $\overset{(-)}{\nu_\mu}$ CC component suffers of an important contamination from NC events at low energy, which is under study. Preliminary results are presented.Comment: Proceeding for poster presented at the 7th Roma International Conference on AstroParticle Physic

Potential of Core-Collapse Supernova Neutrino Detection at JUNO

JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

Detection of the Diffuse Supernova Neutrino Background with JUNO

As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

Atmospheric Neutrino Physics with JUNO

The atmospheric neutrino flux represents a natural source that can be exploited to infer properties about Cosmic Rays and neutrino oscillation physics. The JUNO observatory, a 20 kt liquid scintillator detector currently under construction in China, will be able to detect the atmospheric flux, given the large volume and the excellent energy resolution. In this study, a sample of atmospheric neutrinos Monte Carlo events has been generated from theoretical models and then processed by a full Geant4 - based simulation, which propagates all particles and light inside the detector. The different time evolution of light allows to discriminate the flavor of primary neutrinos. A probabilistic unfolding method has been used, in order to infer the primary neutrino energy spectrum from the detector output. The simulated spectrum has been reconstructed between 100 MeV and 10 GeV, showing a great potential of the detector in the atmospheric low energy region

First detection of solar neutrinos from the CNO cycle with the Borexino detector

Neutrinos are elementary particles which are known since many years as fundamental messengers from the interior of the Sun. The Standard Solar Model, which gives a theoretical description of all nuclear processes which happen in our star, predicts that roughly 99% of the energy produced is coming from a series of processes known as the “pp-chain”. Such processes have been studied in detail over the last years by means of neutrinos, thanks also to the important measurements provided by the Borexino experiment. The remaining 1% is instead predicted to come from a separate loop-process, known as the “CNO cycle”. This sub-dominant process is theoretically well understood, but has so far escaped any direct observation. Another fundamental aspect is that the CNO cycle is indeed the main nuclear engine in stars more massive than the Sun.In 2020, thanks to the unprecedented radio-purity and temperature control achieved by the Borexino detector over recent years, the first ever detection of neutrinos from the CNO cycle has been finally announced. The milestone result confirms the existence of this nuclear fusion process in our Universe. Here, the details of the detector stabilization and the analysis techniques adopted are reported. Final results are discussed, together with the implications for solar physics and astrophysics

JUNO Non-oscillation Physics

The JUNO observatory, a 20 kt liquid scintillator detector to be completed in 2022 in China, belongs to the next-generation of neutrino detectors, which share the common features of having a multi-ton scale and an energy resolution at unprecedented levels.Beside the ambitious goal of neutrino mass ordering determination, the JUNO Collaboration plans also to perform a wide series of other measurements in the neutrino and astroparticle fields, rare processes and searches for new physics. The detector characteristics will allow the detection of neutrinos from many sources, like supernovae, the Sun, atmospheric and geoneutrinos. Other potential studies accessible to JUNO include the search for exotic processes, such as nucleon decays, Dark Matter and magnetic monopoles interactions, light sterile neutrinos production.This talk will review the potential of JUNO about non-oscillation physics, highlighting the unique contributions that the experiment will give to the various fields in the forthcoming years

Spectral fit of Borexino Phase-III data for the detection of CNO solar neutrinos

Borexino experiment, located at the Laboratori Nazionali del Gran Sasso, was built with a primary goal of the low-energy solar neutrino detection. In more than 12 years of data taking, Borexino has demonstrated the unprecedentedly high sensitivity towards solar neutrinos from the complete pp-chain, dominant process in the Sun fusion. After a number of developments in both hardware and software, Borexino is now ready to tackle the measurement of neutrinos produced in a subdominant Carbon-Nitrogen-Oxygen (CNO) cycle mechanism. One of the key steps of the analysis is the performance of spectral fit to disentangle neutrino signals from backgrounds in the detector. All the important aspects of the performed spectral fits are explained in the poster

Borexino Results on Neutrinos from the Sun and Earth

Borexino is a 280-ton liquid scintillator detector located at the Laboratori Nazionali del Gran Sasso in Italy. Since the start of its data-taking in May 2007, it has provided several measurements of low-energy neutrinos from various sources. At the base of its success lie unprecedented levels of radio-purity and extensive thermal stabilization, both resulting from a years-long effort of the collaboration. Solar neutrinos, emitted in the Hydrogen-to-Helium fusion in the solar core, are important for the understanding of our star, as well as neutrino properties. Borexino is the only experiment that has performed a complete spectroscopy of the pp chain solar neutrinos (with the exception of the hep neutrinos contributing to the total flux at 10$^{−5}$ level), through the detection of pp, $^7$Be, pep, and $^8$B solar neutrinos and has experimentally confirmed the existence of the CNO fusion cycle in the Sun. Borexino has also detected geoneutrinos, antineutrinos from the decays of long-lived radioactive elements inside the Earth, that can be exploited as a new and unique tool to study our planet. This paper reviews the most recent Borexino results on solar and geoneutrinos, from highlighting the key elements of the analyses up to the discussion and interpretation of the results for neutrino, solar, and geophysics

Towards a reconstruction of Supernova Neutrino Spectra in JUNO

Observation of supernovae (SN) through their neutrino emission is a fundamental point to understand both SN dynamics and neutrino physical properties. JUNO is a 20kton liquid scintillator detector, under construction in Jiangmen, China. The main aim of the experiment is to determine neutrino mass hierarchy by precisely measuring the energy spectrum of reactor electron antineutrinos. However due to its properties, JUNO has the capability of detecting a high statistics of SN events too. Existing data from SN neutrino consists only of 24 events coming from the SN 1987A,the detection of a SN burst in JUNO at ~ 10kpc will yield ~ 5x103 inverse beta decay (IBD) events from electron antineutrinos, about 1500 from proton elastic scattering (pES) above the threshold of 0.2 MeV, about 400 from electron elastic scattering (eES), plus several hundreds on other CC and NC interaction channels from all neutrino species