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Measuring q 13 with Reactors Stuart Freedman HEPAP July 24, 2003 Bethesda

Measuring q 13 with Reactors Stuart Freedman HEPAP July 24, 2003 Bethesda. d 2. d 1. Detector 2. Detector 1. Reactor. MNSP Matrix.  12 ~ 30°. tan 2  13 < 0.03 at 90% CL.  23 ~ 45°. Mass Hierarchy. Figuring out CP for leptons. Minakata and Nunokawa, hep-ph/0108085.

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Measuring q 13 with Reactors Stuart Freedman HEPAP July 24, 2003 Bethesda

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  1. Measuring q 13 with Reactors Stuart Freedman HEPAP July 24, 2003 Bethesda d2 d1 Detector 2 Detector 1 Reactor

  2. MNSP Matrix 12 ~ 30° tan2 13 < 0.03 at 90% CL 23 ~ 45° Mass Hierarchy

  3. Figuring out CP for leptons Minakata and Nunokawa, hep-ph/0108085

  4. The Basic Idea 1/r2 Pee, (4 MeV) eflux ?

  5. First Direct Detection of the Neutrino E = 2200 keV n e e+ E = 511 keV E = 511 keV n m Reines and Cowan 1956

  6. Neutrino Spectra from Principal Reactor Isotopes

  7. Inverse Beta Decay Cross Section and Spectrum

  8. Inverse Beta Decay Signal from KamLAND from 12C(n, g ) tcap = 188 +/- 23 msec

  9. 20 m KamLAND 4 m Chooz 1m Long Baseline Reactor Neutrino Experiments Poltergeist

  10. CHOOZ

  11. CHOOZ

  12. KamLAND

  13. Future 13 Reactor Experiment detector 1 detector 2 Ratio of Spectra Energy (MeV) Two Detector Reactor Experiment Spectral Ratio

  14. Sensitivity to sin2213 at 90% CL cal relative near/far energy calibration norm relative near/far flux normalization Reactor I 12 t, 7 GWth, 5 yrs Reactor II 250 t, 7 GWth, 5 yrs Chooz 5 t, 8.4 GWth, 1.5 yrs fit to spectral shape Ref: Huber et al., hep-ph/0303232 Reactor-I: limit depends on norm (flux normalization) Reactor-II: limit essentially independent of norm statistical error only

  15. We need accelerators and reactors--Reactors first! Reactor Neutrino Measurement of 13 • No matter effect • Correlations are small, no degeneracies • Independent of solar parameters 12, m212 Sensitivity to sin2213 Ref: Huber et al., hep-ph/0303232 • sin2213 < 0.01-0.02 @ 90 CL within reach of reactor 13 experiments • Knowing 13 is useful for the “intelligent design” of a CP experiments. 10-3 10-2 10-1

  16. Huber et al hep-ph/03030232

  17. ~20000 ev/year ~1.5 x 106 ev/year Kr2Det: Reactor 13 Experiment at Krasnoyarsk Features - underground reactor - existing infrastructure Detector locations constrained by existing infrastructure Reactor Ref: Marteyamov et al, hep-ex/0211070

  18. Lnear= 115 m, Lfar=1000 m, Nfar = 16000/yr Ratio of Spectra Ratio of Spectra Kr2Det: Reactor 13 Experiment at Krasnoyarsk Energy (MeV) Ref: Marteyamov et al., hep-ex/0211070.

  19. Proposal for Reactor 13 Experiment in Japan Kashiwazaki-7 nuclear power stations, World’s most powerful reactors - requires construction of underground shaft for detectors far near near Kashiwazaki-Kariwa Nuclear Power Station

  20. Kashiwazaki:Proposal for Reactor 13 Experiment in Japan far near near 70 m 70 m 200-300 m 6 m shaft, 200-300 m depth

  21. q13 at a US nuclear power plant? Site Requirements • powerful reactors • overburden • controlled access

  22. Berkeley 230 miles Pasadena 200 miles

  23. 2 underground  detectors Diablo Canyon Nuclear Power Plant 1500 ft • Powerful: Two reactors (3.1+ 3.1 GW Eth) • Overburden: Horizontal tunnel could give 800 mwe shielding • Infrastructure: Construction roads. Controlled access. Close to wineries.

  24. Detector Concept

  25. Requirements: Overburden and Large Detectors Detector Event Rate/Year ~250,000 ~60,000 ~10,000 Statistical error: stat ~ 0.5%for L = 300t-yr

  26. Overburden FAR: ~ 600-800 mwe NEAR: ~ 300-400 mwe Neutrino Detectors at Diablo Canyon • 2 neutrino detectors, railroad-car size • in tunnels at (variable) distance of NEAR/FAR I: 0.5-1 km FAR II: 1.5-3 km Possible location Crowbar Canyon Parallel to Diablo Canyon Existing road access Possibility for good overburden Tunnels in radial direction from reactor Crowbar Canyon parallel to Diablo Canyon

  27. Optimization ‘far-far’L1=6 km L2=7.8 km ‘near-far’L1 = 1 km L2 = 3 km MC Studies Oscillation Parameters: sin2213 = 0.14 m2= 2.5 x 10-3 eV2

  28. Reactor 13 13 Reactor results will define the future of CP searches in the lepton sector and complement accelerator experiments Timescale and Size of a 13Reactor Project Moderate Scale ( < $50M )Medium-size, low-energy experiment Little R&D necessary (KamLAND, SNO, CHOOZ)Construction time ~ 2-3 yrsStart in 2007/2008? The Particle Physics Roadmap (in the US) 2000 2005 2010 m223, 23 CP

  29. Conclusions • Top priorities in neutrino physics include pinning down • MNS matrix elements and discovering CP violation. • We will need a number of experiments to resolve ambiguities from matter effects and correlations. • Reactor experiments and accelerator experiments are complementary. • Reactor experiments have the potential of being faster, cheaper and better for establishing the value of q13. • Executing a reactor experiment at an appropriate site should be put on a fast track.

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