9/14/06- S. DyeNOW A Deep Ocean Anti-Neutrino Observatory An Introduction to the Science Potential of Hanohano Presented by Steve Dye University of Hawaii at Manoa Hawaii Pacific University

9/14/06- S. DyeNOW Outline Neutrino Geophysics –U/Th mantle flux –Th/U ratio –Geo-reactor search Neutrino Oscillation Physics –Mixing angles θ 12 and θ 13 –Mass squared difference Δm 2 31 –Mass hierarchy

9/14/06- S. DyeNOW Hawaii Anti-Neutrino Observatory † Location flexibility –Far from continental crust and reactors for neutrino geophysics- Hawaii –Offshore of reactor for neutrino oscillation physics- California, Taiwan Technological issues being addressed –Scintillating oil studies: P = 450 atm., T = 0°C –Implosion studies at sea –Engineering studies of detector structure, deployment † hanohano- Hawaiian for distinguished *

9/14/06- S. DyeNOW Hanohano- 10x “KamLAND” in ocean Construct in shipyard, fill/test in port, tow to site, and submerge to ~4 km

9/14/06- S. DyeNOW Preliminary reference Earth model Knowledge of Earth interior from seismology Dziewonski and Anderson, Physics of the Earth and Planetary Interiors 25 (1981)

9/14/06- S. DyeNOW Bulk silicate Earth model Knowledge of Earth composition largely model dependent. “Standard Model” based on 3 meteorite samples. McDonough and Sun, Chemical Geology 120 (1995)

9/14/06- S. DyeNOW Terrestrial heat flow: TW Hofmeister and Criss, Tectonophysics 395 (2005) Pollack, Hurter, and Johnson, Reviews of Geophysics 31(3) (1993) Present controversy over hydrothermal flow

9/14/06- S. DyeNOW Geo-neutrinos- parent spectrum thorium chain uranium chain Threshold for Reines and Cowan coincidence technique prompt delayed No direction or K neutrinos yet

9/14/06- S. DyeNOW Predicted geo-neutrino signal F. Mantovani et al., Phys. Rev. D 69 (2004) BorexinoSNO+KamLAND Hanohano Simulated event source distribution Signal mostly from <500 km Crust dominates on continents Mantle dominates in ocean

9/14/06- S. DyeNOW Geo-ν + background spectra Cosmic ray muons alpha source Radioactive materials fast neutrons spallation products Target Volume μ±μ± μ±μ± Background manageable

9/14/06- S. DyeNOW Hanohano: mantle measurement 15 years of SNO+ 48 years of Borexino 1 year of Hanohano

9/14/06- S. DyeNOW Hanohano: mantle measurement Mantle (ev / 10 kT-y) Hanohano has ultimate sensitivity of <10%. Continental detectors cannot measure the mantle flux to better than 50%. Limiting factor 20% systematic uncertainty in U/Th content. 20% in 1 year

9/14/06- S. DyeNOW Earth Th/U ratio measurement Project crust type δR/R (1 yr exposure) Th/U (1 yr exposure) Years to 10% measurement KamLAND island arc ± 8390 Borexino continental 1.14 ± 4120 SNO+ continental ± Hanohano oceanic ± Statistical uncertainties only; includes reactors

9/14/06- S. DyeNOW Anti-neutrinos from the core? Geo-reactor hypothesis Herndon hypothesis- natural fission reactor in core of Earth P = 1-10 TW Controversial but not ruled out Herndon, Proc. Nat. Acad. Sci. 93 (1996) 646. Hollenbach and Herndon, Proc. Nat. Acad. Sci. 98 (2001)

9/14/06- S. DyeNOW Geo-reactor search Project crust type Power limit 99% CL (TW) 5σ discovery power (TW) KamLAND island arc 2251 Borexino continental 1243 SNO+ continental 922 Hanohano oceanic year run time- statistical uncertainties only Power upper limit Geo-reactor power (TW) ~few TW needed to drive geomagnetic field

9/14/06- S. DyeNOW ν mixing: Reactor neutrinos P ee = 1-{cos 4 (θ 13 )sin 2 (2θ 12 )sin 2 (Δm 2 21 L/4E) + cos 2 (θ 12 )sin 2 (2θ 13 )sin 2 (Δm 2 31 L/4E) + sin 2 (θ 12 )sin 2 (2θ 13 )sin 2 (Δm 2 32 L/4E)} Each amplitude cycles with own frequency ½-cycle measurements –mixing angles, mass-squared differences Multi-cycle measurements –Mixing angles, mass-squared differences –Potential for mass hierarchy

9/14/06- S. DyeNOW Reactor ν mixing parameters: present knowledge KamLAND combined analysis: tan 2 (θ 12 ) = 0.40( / – 0.07) Δm 2 21 =(7.9 ± 0.7) × eV 2 Araki et al., Phys. Rev. Lett. 94 (2005) CHOOZ limit: sin 2 (2θ 13 ) ≤ 0.20 Apollonio et al., Eur. Phys. J. C27 (2003) SuperK and K2K: Δm 2 31 =(2.5 ± 0.5) × eV 2 Ashie et al., Phys. Rev. D64 (2005) Aliu et al., Phys. Rev. Lett. 94 (2005)

9/14/06- S. DyeNOW ν e flux measurement uncertainty Flux from distant, extended source like Earth or sun is fully mixed P(ν e → ν e ) = 1-0.5{cos 4 (θ 13 )sin 2 (2θ 12 ) + sin 2 (2θ 13 )} = ( /-0.091) Lower value for maximum angles Upper value for minimum angles Φ source = Φ detector /P(ν e → ν e ) Uncertainty is +15%/-6%

9/14/06- S. DyeNOW Suggested ½-cycle θ 12 measurement Reactor experiment- ν e point source P(ν e → ν e ) ≈ 1-sin 2 (2θ 12 )sin 2 (Δm 2 21 L/4E) 60 GW·kT·y exposure at km –~4% systematic error from near detector –sin 2 (θ 12 ) measured with ~2% uncertainty Bandyopadhyay et al., Phys. Rev. D67 (2003) Minakata et al., hep-ph/ Bandyopadhyay et al., hep-ph/

9/14/06- S. DyeNOW Proposed ½-cycle θ 13 measurements Reactor experiment- ν e point source P(ν e → ν e ) ≈ 1-sin 2 (2θ 13 )sin 2 (Δm 2 31 L/4E) Double Chooz, Daya Bay, Reno- measure θ 13 with “identical” near/far detector pair –sin 2 (2θ 13 ) ≤ in few years –Solar and matter insensitive –Challenging systematics Mikaelyan and Sinev, Phys. Atom. Nucl. 62 (1999) Anderson et al., hep-ex/

9/14/06- S. DyeNOW Reactor antineutrino spectra- 50 km 1,2 oscillations with sin 2 (2θ 12 )=0.82 and Δm 2 21 =7.9x10 -5 eV 2 1,3 oscillations with sin 2 (2θ 13 )=0.10 and Δm 2 31 =2.5x10 -3 eV 2 no oscillation oscillations no oscillation oscillations Neutrino energy (MeV) L/E (km/MeV) Distance/energy, L/E Energy, E Plots by jgl

9/14/06- S. DyeNOW Fourier Transform on L/E to Δm 2 Fourier Power, Log Scale Spectrum w/ θ 13 =0 Δm 2 /eV 2 Preliminary- 10 kt-y exposure at 50 km range sin 2 (2θ 13 )≥0.05 Δm 2 31 = eV 2 to % level Learned, Pakvasa, Svoboda, SD preprint in preparation Δm 2 32 < Δm 2 31 normal hierarchy Δm 2 (x10 -2 eV 2 ) Peak due to nonzero θ 13 Includes energy smearing- 3.5%/√E Plots by jgl

9/14/06- S. DyeNOW Neutrino mass hierarchy- reactor neutrinos m3m3 m3m3 m2m2 m1m1 m1m1 m2m2 normalinverted |Δm 2 31 | > |Δm 2 32 ||Δm 2 31 | < |Δm 2 32 | mass Δm 2 32 ≈ (1.00 ± 0.03) Δm 2 31 Petcov and Piai, Phys. Lett. B533 (2001) Exposure and energy resolution are critical for this determination are currently under study

9/14/06- S. DyeNOW Hanohano- candidate reactor sites San Onofre- ~6 GW th Maanshan- ~5 GW th

9/14/06- S. DyeNOW Hanohano- 10 kT-y exposure Neutrino Geophysics- near Hawaii –Mantle flux U/Th geo-neutrinos to ~25% –Measure Th/U ratio to ~20% –Rule out geo-reactor of P > 0.3 TW Neutrino Oscillation Physics- ~60 km by reactor –Measure sin 2 (θ 12 ) to few % w/ standard ½-cycle –Measure sin 2 (2θ 13 ) down to ~ 0.05 w/ multi-cycle –Δm 2 31 at percent level w/ multi-cycle –potential for mass hierarchy if θ 13 >0 without near detector; insensitive to background, systematics; complimentary to Minos, Nova

9/14/06- S. DyeNOW Conclusion Hanohano –10 kT deep ocean anti-neutrino observatory –Movable for multi-disciplinary science Neutrino geophysics Neutrino oscillation physics – Under development at Hawaii; continuing funding from U.S. Department of Defense –1 st collaboration meeting 3/07 Interested?