Synergies and Prospects for Early Resolution of the Neutrino Mass Ordering

The measurement of neutrino Mass Ordering (MO) is a fundamental element for the understanding of leptonic flavour sector of the Standard Model of Particle Physics. Its determination relies on the precise measurement of $\Delta m^2_{31}$ and $\Delta m^2_{32}$ using either neutrino vacuum oscillations, such as the ones studied by medium baseline reactor experiments, or matter effect modified oscillations such as those manifesting in long-baseline neutrino beams (LB$\nu$B) or atmospheric neutrino experiments. Despite existing MO indication today, a fully resolved MO measurement ($\geq$5$\sigma$) is most likely to await for the next generation of neutrino experiments: JUNO, whose stand-alone sensitivity is $\sim$3$\sigma$, or LB$\nu$B experiments (DUNE and Hyper-Kamiokande). Upcoming atmospheric neutrino experiments are also expected to provide precious information. In this work, we study the possible context for the earliest full MO resolution. A firm resolution is possible even before 2028, exploiting mainly vacuum oscillation, upon the combination of JUNO and the current generation of LB$\nu$B experiments (NOvA and T2K). This opportunity is possible thanks to a powerful synergy boosting the overall sensitivity where the sub-percent precision of $\Delta m^2_{32}$ by LB$\nu$B experiments is found to be the leading order term for the MO earliest discovery. We also found that the comparison between matter and vacuum driven oscillation results enables unique discovery potential for physics beyond the Standard Model.Comment: Entitled in arXiv:2008.11280v1 as "Earliest Resolution to the Neutrino Mass Ordering?

TAO Conceptual Design Report: A Precision Measurement of the Reactor Antineutrino Spectrum with Sub-percent Energy Resolution

The Taishan Antineutrino Observatory (TAO, also known as JUNO-TAO) is a satellite experiment of the Jiangmen Underground Neutrino Observatory (JUNO). A ton-level liquid scintillator detector will be placed at about 30 m from a core of the Taishan Nuclear Power Plant. The reactor antineutrino spectrum will be measured with sub-percent energy resolution, to provide a reference spectrum for future reactor neutrino experiments, and to provide a benchmark measurement to test nuclear databases. A spherical acrylic vessel containing 2.8 ton gadolinium-doped liquid scintillator will be viewed by 10 m^2 Silicon Photomultipliers (SiPMs) of >50% photon detection efficiency with almost full coverage. The photoelectron yield is about 4500 per MeV, an order higher than any existing large-scale liquid scintillator detectors. The detector operates at -50 degree C to lower the dark noise of SiPMs to an acceptable level. The detector will measure about 2000 reactor antineutrinos per day, and is designed to be well shielded from cosmogenic backgrounds and ambient radioactivities to have about 10% background-to-signal ratio. The experiment is expected to start operation in 2022

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

The spectrum of Spitz nevi: a clinicopathologic study of 83 cases.

OBJECTIVE: To achieve a clinicopathologic classification of Spitz nevi by comparing their clinical, dermoscopic, and histopathologic features. DESIGN: Eighty-three cases were independently reviewed by 3 histopathologists and preliminarily classified into classic or desmoplastic Spitz nevus (CDSN, n = 11), pigmented Spitz nevus (PSN, n = 14), Reed nevus (RN, n = 16), or atypical Spitz nevus (ASN, n = 14); the remaining 28 cases were then placed into an intermediate category (pigmented Spitz-Reed nevus, PSRN) because a unanimous diagnosis of either PSN or RN was not reached. SETTING: University dermatology and pathology departments and general hospital pathology departments. PATIENTS: A sample of subjects with excised melanocytic lesions. MAIN OUTCOME MEASURE: Frequency of dermoscopic patterns within the different histopathologic subtypes of Spitz nevi. RESULTS: Overlapping clinical, dermoscopic, and histopathologic findings were observed among PSN, RN, and PSRN, thereby justifying their inclusion into the single PSRN diagnostic category. Asymmetry was the most frequent indicator of histopathologic ASN (79%; n = 11); in only 4 cases did dermoscopic asymmetry show no histopathologic counterpart, and in those cases the discrepancy was probably the result of an artifact of the gross sampling technique carried out with no attention to the dermoscopic features. CONCLUSIONS: Among Spitz nevi, histopathologic distinction between PSN and RN is difficult, not reproducible, and may be clinically useless. A simple clinicopathologic classification of these neoplasms might therefore be structured as CDSN, PSRN, and ASN. Asymmetry should be assessed using both dermoscopic and histopathologic analysis, and reliability in histopathologic diagnosis may be enhanced by the simultaneous evaluation of the corresponding dermoscopic images

Three-point checklist of dermoscopy: A new screening method for early detection of melanoma

Background: Dermoscopy used by experts has been demonstrated to improve the diagnostic accuracy for melanoma. However, little is known about the diagnostic validity of dermoscopy when used by nonexperts. Objective: To evaluate the diagnostic performance of nonexperts using a new 3-point checklist based on a simplified dermoscopic pattern analysis. Methods: Clinical and dermoscopic images of 231 clinically equivocal and histopathologically proven pigmented skin lesions were examined by 6 nonexperts and 1 expert in dermoscopy. For each lesion the nonexperts assessed 3 dermoscopic criteria (asymmetry, atypical network and blue-white structures) constituting the 3-point method. In addition, all examiners made an overall diagnosis by using standard pattern analysis of dermoscopy. Results: Asymmetry, atypical network and blue-white structures were shown to be reproducible dermoscopic criteria, with a kappa value ranging from 0.52 to 0.55. When making the overall diagnosis, the expert had 89.6% sensitivity for malignant lesions (tested on 68 melanomas and 9 pigmented basal cell carcinomas), compared to 69.7% sensitivity achieved by the nonexperts. Remarkably, the sensitivity of the nonexperts using the 3-point checklist reached 96.3%. The specificity of the expert using overall diagnosis was 94.2% compared to 82.8 and 32.8% achieved by the nonexperts using overall diagnosis and 3-point checklist, respectively. Conclusion: The 3-point checklist is a valid and reproducible dermoscopic algorithm with high sensitivity for the diagnosis of melanoma in the hands of non-experts. Thus it may be applied as a screening procedure for the early detection of melanoma. Copyright (C) 2004 S. Karger AG, Basel