1. Unofficial* summary of the Long Baseline Neutrino Experiment (LBNE) physics workshop Seattle, Aug 9 to Aug 11 David Webber August 24, 2010 *Many studies/plots are preliminary. These slides are a representation of the workshop’s discussion. An official report is in preparation by the collab.

2. Why Study Neutrinos? Neutrinos are half the known stable particles in the universe –       p, e,  Neutrinos are a major component of the universe – ~300 /cm 3, roughly same as CMB photons – nucleons and electrons are ~10 -7 /cm 3 Neutrinos allow for the study of particle physics, without the complications of strong and electromagnetic forces. Svoboda

3. Neutrino Physics Goals Svoboda

4. neutrino

5. Svoboda

11. Far Detector Options Water 100 kT fiducial module. 4850 ft depth. 15% or 30% HQE PMT coverage? Gadolineum or not? 1,2,3 modules? More signal! – Larger volume Liquid Argon 17 kT fiducial module. 300, 800, 4850 ft depth? 3, 4, 5 mm wire spacing? – Probably will be 3 mm photon trigger? 1,2,3 modules? Less background! – Better  0 identification 100 kT water ~= 17 kT liquid Ar for beam physics sensitivity

12. Far Detector Configurations

14. Long Baseline Physics: CP violation and neutrino hierarchy

15. Svoboda300 kT water ~= 50 kT liquid Ar for beam physics sensitivity

16. LBNE could push to 3-4 x 10 -3 (see talk by Zeller)

17. Svoboda

18. Proton Decay

19. Svoboda

21. Galactic Supernova Burst

23. Scholberg

26. Neutrino hierarchy determination from a galactic supernova burst David Webber August 20, 2010

27. H. Duan and A. Friedland, http://arxiv.org/abs/1006.2359http://arxiv.org/abs/1006.2359 Neutrino energies at infinity (1 second late-time slice of 10-second burst spectrum)

28. Consider 3 detector possibilities Water Cherenkov (WC) with 30% phototube coverage and high quantum-efficiency tubes – This is roughly equivalent to Super-K’s coverage WC, 15% coverage, HQE Liquid Argon

29. reaction cross-sections https://wiki.bnl.gov/dusel/index.php/Event_Rate_Calculatio ns Dominant reaction: WaterArgon Dominant reaction:

30. Normal Hierarchy: Observed Spectra (accounts for detector acceptance) WC 30% coverage flux at detector WC 15% coverageLiquid Ar

31. Inverted Hierarchy: Observed Spectra (accounts for detector acceptance) WC 30% coverage flux at detector WC 15% coverageLiquid Ar

32. How many events are needed to distinguish normal from inverted hierarchy in water? Normal HierarchyInverted Hierarchy 10 2 events indistinguishable Water Detector 30% PMT coverage HQE tubes IBD reaction  2 shown for “wrong” fit 10 5 events clearly distinguishable

33. How many events for 3 sigma exclusion? Note:    is not the same as Gaussian “3 sigma” = 99.73% confidence 99.73% confidence is… –  2 /NDF of 1.6 for 57 degrees of freedom –  2 /NDF of 1.8 for 34 degrees of freedom

34.  2 vs. events, WC, 30% coverage Normal hierarchy Inverted hierarchy Normal fitInverted fit Water Detector 30% PMT coverage HQE tubes IBD reaction ~10 3.5-3.6 = 3200-4000 events are needed

35.  2 vs. events, WC, 15% coverage Normal hierarchy Inverted hierarchy Normal fitInverted fit Water Detector 15% PMT coverage HQE tubes IBD reaction ~10 3.5-3.6 = 3200-4000 events are needed

36. How many events are needed to distinguish normal from inverted hierarchy in argon? Normal HierarchyInverted Hierarchy 10 2 events indistinguishable 10 5 events clearly distinguishable Liquid Argon  2 shown for “wrong” fit

37.  2 vs. events, liquid argon Normal hierarchy Inverted hierarchy Normal fitInverted fit ~10 2.7-2.8 = 500-630 events are needed

38. Normal and inverted hierarchy neutrino spectra for 99.7% confidence. Normal HierarchyInverted Hierarchy Liquid Argon 630 events Water Cherenkov 30% PMT coverage 4000 events

39. Summary WC phototube coverage has little impact on resolving the hierarchy. – 15% is as good as 30% To resolve the hierarchy… – ~4000 events must be observed in water, or – ~630 events must be observed in argon If a SNB occurs at 8.5 kpc… – Need 18.3 kT water – Need 7.6 kT Ar – a 100kT water module would have better statistics than a 17 kT LAr module – The LAr module would show more interesting spectral features Volume estimates based on http://arxiv.org/abs/astro-ph/0701081http://arxiv.org/abs/astro-ph/0701081 This study was based on repository revision 754

40. Confidence vs. Events See other slides SNB Hierarchy study improvements: Allow more parameters to fit in my study to allow for spectral shifts and broadening, eg. E --> E_0 + m*E Perform a multi-module simultaneous for Argon (nue) and Water (nuebar).

41. LBNE Workshop Summary Choice of far detector is currently undecided – There are many choices Liquid Argon has not been attempted at this size – possibility for something new – technical risk Details of each detector are still under consideration

42. Far Detector Options Water 100 kT fiducial module. 4850 ft depth. 15% or 30% HQE PMT coverage? Gadolineum or not? 1,2,3 modules? More signal! – Larger volume Liquid Argon 17 kT fiducial module. 300, 800, 4850 ft depth? 3, 4, 5 mm wire spacing? – Probably will be 3 mm photon trigger? 1,2,3 modules? Less background! – Better  0 identification 100 kT water ~= 17 kT liquid Ar for beam physics sensitivity

43. References http://www.int.washington.edu/talks/WorkSh ops/int_10_2b/, Aug 9-10 http://www.int.washington.edu/talks/WorkSh ops/int_10_2b/