SNO+ is a large liquid scintillator-based experiment located 2 km underground at SNOLAB, Sudbury, Canada. It reuses the Sudbury Neutrino Observatory detector, consisting of a 12 m diameter acrylic vessel which will be filled with about 780 tonnes of ultra-pure liquid scintillator. Designed as a multipurpose neutrino experiment, the primary goal of SNO+ is a search for the neutrinoless double-beta decay (0νββ) of130Te. In Phase I, the detector will be loaded with 0.3% natural tellurium, corresponding to nearly 800 kg of130Te, with an expected effective Majorana neutrino mass sensitivity in the region of 55–133 meV, just above the inverted mass hierarchy. Recently, the possibility of deploying up to ten times more natural tellurium has been investigated, which would enable SNO+ to achieve sensitivity deep into the parameter space for the inverted neutrino mass hierarchy in the future. Additionally, SNO+ aims to measure reactor antineutrino oscillations, low energy solar neutrinos, and geoneutrinos, to be sensitive to supernova neutrinos, and to search for exotic physics. A first phase with the detector filled with water will begin soon, with the scintillator phase expected to start after a few months of water data taking. The0νββPhase I is foreseen for 2017.

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New developments in liquid scintillators, highefficiency, fast photon detectors, and chromatic photon sorting have opened up the possibility for building a large-scale detector that can discriminate between Cherenkov and scintillation signals. Such a detector could reconstruct particle direction and species using Cherenkov light while also having the excellent energy resolution and low threshold of a scintillator detector. Situated deep underground, and utilizing new techniques in computing and reconstruction, this detector could achieve unprecedented levels of background rejection, enabling a rich physics program spanning topics in nuclear, high-energy, and astrophysics, and across a dynamic range from hundreds of keV to many GeV. The scientific program would include observations of low-and high-energy solar neutrinos, determination of neutrino mass ordering and measurement of the neutrino CP-violating phase δ, observations of diffuse supernova neutrinos and neutrinos from a supernova burst, sensitive searches for nucleon decay and, ultimately, a search for neutrinoless double beta decay, with sensitivity reaching the normal ordering regime of neutrino mass phase space. This paper describes Theia, a detector design that incorporates these new technologies in a practical and affordable way to accomplish the science goals described above.

Hyper-Kamiokande will be a next generation underground water Cherenkov detector with a total (fiducial) mass of 0.99 (0.56) million metric tons, approximately 20 (25) times larger than that of Super-Kamiokande. One of the main goals of Hyper-Kamiokande is the study of CP asymmetry in the lepton sector using accelerator neutrino and anti-neutrino beams.In this document, the physics potential of a long baseline neutrino experiment using the Hyper-Kamiokande detector and a neutrino beam from the J-PARC proton synchrotron is presented. The analysis has been updated from the previous Letter of Intent [K. Abe et al., arXiv:1109.3262 [hepex]], based on the experience gained from the ongoing T2K experiment. With a total exposure of 7.5 MW × 10 7 sec integrated proton beam power (corresponding to 1.56 × 10 22 protons on target with a 30 GeV proton beam) to a 2.5-degree off-axis neutrino beam produced by the J-PARC proton synchrotron, it is expected that the CP phase δCP can be determined to better than 19 degrees for all possible values of δCP , and CP violation can be established with a statistical significance of more than 3 σ (5 σ) for 76% (58%) of the δCP parameter space.

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This paper reports results from a search for nucleon decay through invisible modes, where no visible energy is directly deposited during the decay itself, during the initial water phase of SNOþ. However, such decays within the oxygen nucleus would produce an excited daughter that would subsequently deexcite, often emitting detectable gamma rays. A search for such gamma rays yields limits of 2.5 × 10 29 y at 90% Bayesian credibility level (with a prior uniform in rate) for the partial lifetime of the neutron, and 3.6 × 10 29 y for the partial lifetime of the proton, the latter a 70% improvement on the previous limit from SNO. We also present partial lifetime limits for invisible dinucleon modes of 1.3 × 10 28 y for nn, 2.6 × 10 28 y for pn and 4.7 × 10 28 y for pp, an improvement over existing limits by close to 3 orders of magnitude for the latter two.

This article describes the physics and nonproliferation goals of WATCHMAN, the WAter Cherenkov Monitor for ANtineutrinos. The baseline WATCHMAN design is a kiloton scale gadolinium-doped (Gd) light water Cherenkov detector, placed 13 kilometers from a civil nuclear reactor in the United States. In its first deployment phase, WATCHMAN will be used to remotely detect a change in the operational status of the reactor, providing a firstever demonstration of the potential of large Gd-doped water detectors for remote reactor monitoring for future international nuclear nonproliferation applications. A demonstration of remote monitoring of a reactor has been called for in the U.S. National Nuclear Security Adminstration's (NNSA) Strategic Plan [1].

A measurement of the 8 B solar neutrino flux has been made using a 69.2 kt-day dataset acquired with the SNOþ detector during its water commissioning phase. At energies above 6 MeV the dataset is an extremely pure sample of solar neutrino elastic scattering events, owing primarily to the detector's deep location, allowing an accurate measurement with relatively little exposure. In that energy region the best fit background rate is 0.25 þ0.09 −0.07 events=kt-day, significantly lower than the measured solar neutrino event rate in that energy range, which is 1.03 þ0.13 −0.12 events=kt-day. Also using data below this threshold, down to 5 MeV, fits of the solar neutrino event direction yielded an observed flux of 2.53 þ0.31 −0.28 ðstatÞ þ0.13 −0.10 ðsystÞ × 10 6 cm −2 s −1 , assuming no neutrino oscillations. This rate is consistent with matter enhanced neutrino oscillations and measurements from other experiments.