Large water based Detectors at the LBNE far

Large water based Detectors at the LBNE far site Large water detectors have a long and distinguished track record. Extensive design and cost information has been developed for LBNE WCD (drawn from Super-K experience) at SURF. For neutrinos 1 Ge. V and proton decay, underground water based detectors are cost effective and well understood. Compliment LBNE LAr detector I have been asked to address the following whitepapers discussing water based detectors that could be located at the LBNE far site: • http: //if-neutrino. fnal. gov/whitepapers/klein-wcd. pdf Large WCD • http: //if-neutrino. fnal. gov/whitepapers/worcester-lowepx. pdf CP with Project-X • http: //if-neutrino. fnal. gov/whitepapers/qian-offaxis. pdf Off-axis LBNE for MH • http: //if-neutrino. fnal. gov/whitepapers/yeh-sci. pdf Water based LS for p+ decay • http: //if-neutrino. fnal. gov/whitepapers/daedalus. pdf Daedalus: CP with cyclotrons 1

LBNE WCD (200 k. Ton) LBNE WCD cost estimate is at or beyond CD-1 level and well understood. Both detector and civil design have had significant engineering. Cost is well beyond “physicist estimate” Schedule: Civil — Detector — Cost: Civil — Detector — ar. Xiv: 1204. 2295 4 years +2 years $300 M $200 M 2

Large WCD • Large-Scale Underground Water Cherenkov Detector at Homestake (http: //if-neutrino. fnal. gov/whitepapers/klein-wcd. pdf) • 4850’ at SURF, 200 k. Ton WCD, complements LBNE 10 k. Ton LAr detector • Estimated cost is $500 M. No R&D needed. • Good CP sensitivity with LBNE beam • Incredibly versatile: p-decay (e+ 0), supernovae, in addition to CP • • • Potential enhancement with high QE PMTs or large area MCP Day/night solar asymmetry Relic supernova background Target for Dae alus Proton decay (K+ ) with water-based liquid scintillator • Strong synergy with existing LBNE program • Clear US leadership (possible competition with Hyper-K or Memphys) 3

WCD with Project-X • Precision Neutrino Oscillation Measurement using Simultaneous High-Power, Low-Energy Project-X Beams (http: //if-neutrino. fnal. gov/whitepapers/worcester-lowepx. pdf), Neutrino Oscillations in the Precision Era ar. Xiv: 1203. 4090 • LBNE upgrade program • 2 nd oscillation maximum is well matched to high-power, low-energy Project-X beams and WCD at far site • Large CP asymmetry and small matter effect • No R&D needed • Clear US leadership • Need Project-X 4

Off-axis LBNE detector for MH enhancement • A second detector at an off-axis location to enhance the mass hierarchy discovery potential of LBNE (http: //if-neutrino. fnal. gov/whitepapers/qian-offaxis. pdf ) • LBNE mass hierarchy reach can be extended by enhancing sensitivity at the 2 nd oscillation maximum • 10 k. Ton WCD 35 km off axis. • WCD well-matched to these lower energy neutrinos(0. 8 Ge. V) Equivalent to 10 k. T LAr detector, but cheaper • WCD can be close to surface • Estimated cost <$50 M 5

DAE ALUS • Whitepaper on the DAE ALUS Experiment (http: //if-neutrino. fnal. gov/whitepapers/daedalus. pdf) • Search for CP violation • Phase 1: one near cyclotron to study anomalies • Phase 2: three to study CP (no matter effect) • Cyclotrons produce neutrinos from decay at rest • Cyclotrons located 1. 5, 8, 20 km from far detector • Need large far detector • Far detector could be large WCD with Gd or could be Wb-LS or LS • Some R&D on accelerators • Estimated cost in category #3 $50–$300 M • Complimentary to LBNE • US leadership — if we build WCD in US 6

Water-Based liquid scintillator for proton decay • A large water-based liquid scintillator detector in search for proton decay p K+ and other physics (http: //if-neutrino. fnal. gov/whitepapers/yeh-sci. pdf) http: //www. sciencedirect. com/science/article/pii/S 0168900211016615 A new water-based liquid scintillator and potential applications • Proton decay: extend reach with both Cherenkov & scintillation light • Positive ID of K+ • Cost effective, long attenuation length • Even greater reach in a 200 k. Ton detector • Cost to modify WCD: cat#2 <$50 M • (build from scratch ~$200 M) • Some R&D • Synergy with 0 , Dark Matter and reactor neutrinos • US leadership 7

Enabling Instrumentation Water based detectors rely on PMTs (or MCPs) for Cherenkov (or scintillation) light detection. Cheaper, high QE photosensors and water based liquid scintillators with large light output and long attenuation length can improve cost performance of large water based detectors. • Cheaper photosensors http: //if-neutrino. fnal. gov/whitepapers/lappd. pdf • Water-based liquid scintillator http: //if-neutrino. fnal. gov/whitepapers/yeh-sci. pdf 8

Enabling Capabilities An underground facility would promote large water based detectors by reducing infrastructure costs associated with these experiments. • • Deep underground facility to support large detectors. High power accelerators High power neutrino beams High power cyclotrons 9

Conclusions WCD as part of the LBNE upgrade plan could offer a rich and versatile physics program • 200 k. Ton WCD at 4850 complements current LBNE program • • • Oscillation physics and CP Adds proton decay and supernovae neutrino Well matched to high power 8 Ge. V Project-X based neutrino beam Well matched to off-axis beam at 2 nd oscillation maximum Can be augmented with WB-LS and/or Gd and extend reach in proton decay, solar day/night, relic supernovae, etc… Little R&D needed as CD-1 level cost estimate already exists. R&D opportunities could bring down the cost Clear US leadership opportunity. Potential competition: Hyper-K and Memphys Strong synergy with LBNE, Dark Matter and 0 through underground facility 10