David Webber August 24, 2010

1. Unofficial* summary of the Long Baseline Neutrino Experiment (LBNE) physics workshopSeattle, 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 • n1, n2, n3, p, e, g • Neutrinos are a major component of the universe • ~300 n/cm3, roughly same as CMB photons • nucleons and electrons are ~10-7/cm3 • Neutrinos allow for the study of particle physics, without the complications of strong and electromagnetic forces. Svoboda

3. Neutrino Physics Goals Svoboda

4. neutrino Svoboda

5. Svoboda

6. Svoboda

7. Svoboda

8. Svoboda

9. Svoboda

10. Svoboda

11. Far Detector Options Water • 100 kTfiducial module. • 4850 ft depth. • 15% or 30% HQE PMT coverage? • Gadolineum or not? • 1,2,3 modules? • More signal! • Larger volume Liquid Argon • 17 kTfiducial 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 p0 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. 300 kT water ~= 50 kT liquid Ar for beam physics sensitivity Svoboda

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

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. n reaction cross-sections Water Argon Dominant reaction: Dominant reaction: https://wiki.bnl.gov/dusel/index.php/Event_Rate_Calculations

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

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

32. How many events are needed to distinguish normal from inverted hierarchy in water? Normal Hierarchy Inverted Hierarchy 102 events indistinguishable 105 events clearly distinguishable • Water Detector • 30% PMT coverage • HQE tubes • IBD reaction • c2 shown for “wrong” fit

33. How many events for 3 sigma exclusion? • Note: c2is not the same as Gaussian • “3 sigma” = 99.73% confidence • 99.73% confidence is… • c2/NDF of 1.6 for 57 degrees of freedom • c2/NDF of 1.8 for 34 degrees of freedom

34. c2 vs. events, WC, 30% coverage Normal fit Inverted fit Normal hierarchy Inverted hierarchy • Water Detector • 30% PMT coverage • HQE tubes • IBD reaction ~103.5-3.6 = 3200-4000 events are needed

35. c2 vs. events, WC, 15% coverage Normal fit Inverted fit Normal hierarchy Inverted hierarchy • Water Detector • 15% PMT coverage • HQE tubes • IBD reaction ~103.5-3.6 = 3200-4000 events are needed

36. How many events are needed to distinguish normal from inverted hierarchy in argon? Normal Hierarchy Inverted Hierarchy 102 events indistinguishable 105 events clearly distinguishable • Liquid Argon • c2 shown for “wrong” fit

37. c2 vs. events, liquid argon Normal fit Inverted fit Normal hierarchy Inverted hierarchy ~102.7-2.8 = 500-630 events are needed

38. Normal and inverted hierarchy neutrino spectra for 99.7% confidence. Normal Hierarchy Inverted Hierarchy Water Cherenkov 30% PMT coverage 4000 events Liquid Argon 630 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 kTAr • a 100kT water module would have better statistics than a 17 kTLAr module • The LAr module would show more interesting spectral features This study was based on repository revision 754 Volume estimates based on http://arxiv.org/abs/astro-ph/0701081

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 kTfiducial module. • 4850 ft depth. • 15% or 30% HQE PMT coverage? • Gadolineum or not? • 1,2,3 modules? • More signal! • Larger volume Liquid Argon • 17 kTfiducial 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 p0 identification 100 kT water ~= 17 kT liquid Ar for beam physics sensitivity

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