Neutrino Physics with JUNO

The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purposeunderground liquid scintillator detector, was proposed with the determinationof the neutrino mass hierarchy as a primary physics goal. It is also capable ofobserving neutrinos from terrestrial and extra-terrestrial sources, includingsupernova burst neutrinos, diffuse supernova neutrino background, geoneutrinos,atmospheric neutrinos, solar neutrinos, as well as exotic searches such asnucleon decays, dark matter, sterile neutrinos, etc. We present the physicsmotivations and the anticipated performance of the JUNO detector for variousproposed measurements. By detecting reactor antineutrinos from two power plantsat 53-km distance, JUNO will determine the neutrino mass hierarchy at a 3-4sigma significance with six years of running. The measurement of antineutrinospectrum will also lead to the precise determination of three out of the sixoscillation parameters to an accuracy of better than 1\%. Neutrino burst from atypical core-collapse supernova at 10 kpc would lead to ~5000inverse-beta-decay events and ~2000 all-flavor neutrino-proton elasticscattering events in JUNO. Detection of DSNB would provide valuable informationon the cosmic star-formation rate and the average core-collapsed neutrinoenergy spectrum. Geo-neutrinos can be detected in JUNO with a rate of ~400events per year, significantly improving the statistics of existing geoneutrinosamples. The JUNO detector is sensitive to several exotic searches, e.g. protondecay via the $p\to K^++\bar\nu$ decay channel. The JUNO detector will providea unique facility to address many outstanding crucial questions in particle andastrophysics. It holds the great potential for further advancing our quest tounderstanding the fundamental properties of neutrinos, one of the buildingblocks of our Universe

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

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

Simulation study on remediation of acid mine drainage by in-situ injection of limestone based sustained release materials

The karst area is widely distributed in China, and the ecological environment is fragile. Acid mine drainage (AMD) produced by mining activities in karst areas seriously threatens the safety of regional ecological environment. In this paper, carbonate rocks and corn cobs (biochar) widely distributed in karst areas were used as raw materials, and an alkaline sustained release material (ASRM) that could be used for in-situ injection and repair was prepared by means of modification, granulation and film coating. In addition, in-situ injection and repair experiments under alternating effects of wet and dry conditions were carried out in the laboratory, to verify and determine the ability and removal mechanism of ASRM in the in-situ remediation of heavy metals in acid mine wastewater. The results showed that ASRM can effectively improve the pH of water, and the pH of AMD can be increased from 2.8 to approximately 5-7, and it had a good removal effect on many harmful heavy metals, such as Fe2+, Mn2+, Zn2+, Cu2+, Cd2+, Pb2+ and Cr3+. XRD and SEM analyses showed that the reaction precipitates mainly existed in the form of FeOOH. The removal mechanism of heavy metals mainly includes: ①some metal ions were removed in the form of precipitation, such as hydroxides produced by the reaction; ②a large amount of FeOOH produced by the reaction system can adsorb and remove heavy metals. This experimental study provides a reliable theoretical and technical basis for the in-situ treatment of AMD in karst mountain mines with high efficiency by using slow-release materials

Disrupted brain functional networks in patients with amblyopia: a resting-state fMRI study

PURPOSE: To explore the topological properties of brain functional networks derived from resting-state functional magnetic resonance imaging in patients with amblyopia. METHODS: Seventeen amblyopic subjects and twenty control subjects were recruited to undergo a resting-state functional magnetic resonance imaging scan. The whole-brain functional networks were constructed for each subject, and topological properties such as small-worldness, network effciency and nodal centrality were quantitatively analyzed with graph theoretical analysis. RESULTS: Both the amblyopic and control groups exhibited small-world properties in brain functional networks, which means a balance between local segregation and global integration for visual information processing. However, compared with control subjects, patients with amblyopia showed altered quantitative values of brain functional networks, characterized with decreased clustering coefficient, lower characteristic path length and decreased network effciency. Topological properties are also significantly altered in some brain regions. These alterations support the disrupted topological organization of brain functional networks in patients with amblyopia. CONCLUSIONS: Amblyopia is partly resulted from the deficits of visual information transmission. Detection and estimation of altered brain functionl networks can help to further understand the pathophysiological mechanism underlying amblyopia.</p