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Fermi momentum Dominated regime

6. 5. 4. 3. E (GeV/c). 2. 1. 0. 0. 1000. 2000. 3000. L (km). Very Long Baseline Neutrino Beams – D m 23 2 Nodes. n = 1. neutrino node pattern is key to high-resolution D m 2 measurements Fermi momentum sets E n >1 GeV/c to maintain n energy resolution

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Fermi momentum Dominated regime

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  1. 6 5 4 3 E (GeV/c) 2 1 0 0 1000 2000 3000 L (km) Very Long Baseline Neutrino Beams – Dm232 Nodes n = 1 • neutrino node pattern is key to high-resolution Dm2 measurements • Fermi momentum sets En>1 GeV/c to maintain n energy resolution • the distance scale is set by Dm232 • BNL happens to be in a perfect location for the next-generation oscillation experiment BNL – Homestake 3 - 4 nodes visible FNAL – Soudan 1 node visible n = 2 n = 3 n = 4 n = 5 Fermi momentum Dominated regime T. Kirk – September 11, 2002 Ref. M. Diwan, August 2002 Figure 1

  2. .006 .005 .004 .003 Dm232 (eV2) .002 .001 .000 0.5 0.6 0.7 0.8 0.9 1.0 Sin2(2q23) Neutrino Experiments Resolution Capability 90% confidence contours • the present Super-K will be improved by factor of 2 • the Minos experiment is limited by the short baseline and the detector • the BNL – Homestake experiment exploits the very long baseline to the Homestake Mine and a very intense n beam • the water Cerenkov method is well matched to the exp. Super-K 2002 Allowed with 90% Confidence Minos 3 years BNL – Homestake 5 years T. Kirk – September 11, 2002 Figure 2 Ref. M. Diwan, August 2002

  3. Potential BNL  Homestake Neutrino Beam BNL Homestake 2540 km Figure 3 T. Kirk September 11, 2002

  4. 250 200 150 Event Yield 100 50 0 0 5 10 Reconstructed En (GeV) BNL-Homestake – nm Disappearance Signal Neutrino Beam – double horn Distance – 2540 km Target – 1 MW @ 2.5 Hz Detector – 0.5 MTon H2O Time – 5 years @ 107 sec/yr Dm122 = .00005; Dm232 = .003 Sin2(2q13) = 0.04 • the neutrino node pattern provides high Dm232 resolution and inherent flux normalization • the background oscillates as well as signal but shifted down in energy • the background signal is measured independently • the geographical aspects are critical to this method (very long earth baseline) No Oscillations 13290 events Signal + Bckg. 6735 events Bckg. Only 1255 events T. Kirk – September 11, 2002 Figure 5 Ref. M. Diwan, August 2002

  5. 250 200 150 Event Yield 100 50 0 5 10 Reconstructed En (GeV) BNL-Homestake – nm Disappearance Signal (Cont.) Neutrino Beam – double horn Distance – 2540 km Target – 1 MW @ 2.5 Hz Detector – 0.5 MTon H2O Time – 5 years @ 107 sec/yr Dm122 = .00005; Dm232 = .001 Sin2(2q13) = 0.04 • the neutrino node pattern provides high Dm232 resolution and inherent flux normalization • the background oscillates as well as signal but shifted down in energy • the background signal is measured independently • the geographical aspects are critical to this method (very long earth baseline) No Oscillations 13290 events Signal + Bckg. 4927 events Bckg. Only 910 events T. Kirk – September 11, 2002 Figure 6 Ref. M. Diwan, August 2002

  6. BNL-Homestake – ne Appearance Signal • the neutrino node pattern provides high Dm232 resolution and inherent flux normalization • the statistics for normal ranges of the parameters are adequate for measuring Dm122 with good accuracy • the background can be measured in a small, near detector if desired (or from other neutrino exps.) • the geographical aspects are critical to this method (very long earth baseline) Neutrino Beam – double horn Distance – 2540 km Target – 1 MW @ 2.5 Hz Detector – 0.5 MTon H2O Time – 5 years @ 107 sec/yr Dm122 = .00006 Dm232 = .002 Sin2(2q13) = 0.04 Signal + Bckg. 346 events Total Bckg. 146 events ne Bckg. 70 events Ref. M. Diwan, August 2002 T. Kirk – September 11, 2002

  7. BNL-Homestake – ne Measurement Sensitivity • for experimentally favored parameter ranges for Dm232 BNL has the best sensitivity to measure Sin2(2q13) • continuing improvements in the BNL beam design expected to improve the Sin2(2q13)sensitivity in the higher Dm2 range • the geographical aspects are critical to this method (very long earth baseline) Favored Dm232 mass range Measureable! Ref. M. Diwan, August 2002 T. Kirk – September 11, 2002

  8. BNL-Homestake –Measurement Summary Dm232 Sin2(2q23) Dm122 Sin2(2q13) d(deg) 0.0035 Dm232 0.002 Sin2(2q13)  0.005 ± 1%± 1% ± 15% ± 10% ± 20º 0.0015  Dm232 0.0004 Sin2(2q13)  0.0025 ± 1% ± 1% ± 15% ± 5% ± 10º ± 1% ± 1% ± 15% no no meas. meas. 0.001  Sin2(2q13) matrix entries are 1 sigma errors for a five-year run @ 107 secs/yr Ref. M. Diwan, August 2002 T. Kirk – September 13, 2002

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