1. LSND/MiniBooNE Follow-up Experiment with DAEdALUS W.C. Louis Los Alamos National Laboratory August 6, 2010

2. 2 Outline LSND & MiniBooNE   e Oscillation Results 3+1 Fit to World Antineutrino Data Testing the LSND/MiniBooNE Signals with DAEdALUS Conclusions

3. 3 LSND Signal LSND experiment Stopped pion beam        +  e +  e Excess of e in  beam e signature: Cherenkov light from e + with delayed  from n-capture Excess=87.9 ± 22.4 ± 6 (3.8  )

4. 4 LSND Signal Assuming two neutrino oscillations Can't reconcile LSND result with atmospheric and solar neutrino using only 3 Standard Model neutrinos – only two independent mass splitings 2 mass

5. 5 Sterile Neutrinos 3+N models N>1 allows CP violation   e ≠   e 2 mass      m 34 2 ~ 0.1 – 100 eV2   m 45 2 ~ 0.1 – 100 eV2

6. 6 MiniBooNE Neutrino Result PRL 102, 101802 (2009) 6.5e20 POT No excess of events in signal region (E>475 MeV) Ruled out simple 2 oscillations as LSND explanation (assuming no CP or CPT violation) SIGNAL REGION Phys. Rev. Lett. 98, 231801 (2007)

7. 7 MiniBooNE Neutrino Result PRL 102, 101802 (2009) Excess of events observed at low energy: 128.8 ± 20.4 ± 38.3 (3.0σ) ‏ Shape not consistent with simple 2 oscillations Magnitude consistent with LSND Anomaly Mediated Neutrino-Photon Interactions at Finite Baryon Density: Jeffrey A. Harvey, Christopher T. Hill, & Richard J. Hill, arXiv:0708.1281 CP-Violation 3+2 Model: Maltoni & Schwetz, arXiv:0705.0107; T. Goldman, G. J. Stephenson Jr., B. H. J. McKellar, Phys. Rev. D75 (2007) 091301. Extra Dimensions 3+1 Model: Pas, Pakvasa, & Weiler, Phys. Rev. D72 (2005) 095017 Lorentz Violation: Katori, Kostelecky, & Tayloe, Phys. Rev. D74 (2006) 105009 CPT Violation 3+1 Model: Barger, Marfatia, & Whisnant, Phys. Lett. B576 (2003) 303 New Gauge Boson with Sterile Neutrinos: Ann E. Nelson & Jonathan Walsh, arXiv:0711.1363

8. 8 MiniBooNE Antineutrino Result 5.66e20 POT arXiv:1007.1150

9. 9 MiniBooNE Antineutrino Null Probability Absolute  2 probability of null point (background only) - model independent Frequentist approach 475-1250 MeV chi2/NDFprobability   e 6.1/640%   e 18.5/60.5%

10. 10 MiniBooNE Oscillation Fit E>475 5.66E20 POT E>475 is signal region for LSND type osc. Oscillations favored over background only hypotheses at 99.4% CL (model dependent) Best fit (sin 2 2 ,  m 2 ) = (0.9584, 0.064 eV 2 )  2 /ND = 16.4/12.6; Prob. = 20.5%  2 /ND = 8.0/4; Prob. = 8.7% (475-1250 MeV)

11. 11 MiniBooNE    e oscillation results appear to confirm the LSND evidence for antineutrino oscillations, although more data are needed E>475 MeV

13. LSND/MiniBooNE Data Compared to 3+N Global Fits (fits from Karagiorgi et al.) 3+1 3+2

14. G. Karagiorgi et al., PRD80, 073001 (2009) Best 3+1 Fit:  m 41 2 = 0.915 eV 2 sin 2 2   e = 0.0043   = 87.9/103 DOF Prob. = 86% Predicts    e disappearance of sin 2 2   ~ 35% and sin 2 2  ee ~ 4.3% 3+1 Global Fit to World Antineutrino Data (with old MiniBooNE data set)

15. 3+N Models Requires Large  Disappearance! In general, P(   e ) < ¼ P(   x ) P( e  x ) Reactor Experiments: P( e  x ) < 5% LSND/MiniBooNE: P(   e ) ~ 0.25% Therefore: P(   x ) > 20%

16. MiniBooNE Neutrino & Antineutrino Disappearance Limits Improved results soon from MiniBooNE/SciBooNE Joint Analysis! A.A. Aguilar-Arevalo et al., PRL 103, 061802 (2009) * * Global best fit

17. 17 Future Experiments MicroBooNE CD1 approved Address MB low energy  excess Statistics too low for antineutrinos Few ideas under consideration: Move or build a MiniBooNE like detector at 200m (LOI arXiv:0910.2698) A new search for anomalous neutrino oscillations at the CERN-PS (arxiv:0909.0355v3) Redoing a stopped pion source at ORNL (OscSNS - http://physics.calumet.purdue.edu/~oscsns/) or DAEdALUS!

18. 18 MiniDAEdALUS Build MiniBooNE-like detector ~300’ (~90m) below cyclotron; (or use large WC detector filled with Gd!) Copy MiniBooNE detector design except for higher PMT coverage (10%->20%) and addition of ~0.031 g/l of b-PBD; cost ~$10-15M Poor cyclotron duty factor compensated by 300’ overburden (cosmic muon rate reduced by factor of ~100) Assume ~ 1 year of data at ~1MW Well understood neutrino fluxes and cross sections Many advantages over LSND: (1) x5 larger detector; (2) x4 higher flux; (2) x100 lower cosmic-muon rate; (3) negligible DIF background; (4) run 12 months per year (instead of 3); (5) larger distance for  m 2 <1 eV 2 implies lower backgrounds;

19. MiniDAEdALUS  -> e  (L/E) ~ 3% ; e p -> e + n (2.2 MeV  )  -> e  (L/E) e - N gs (17.3 MeV e + )  -> s  (L/E)  C* (15.11 MeV  )  -> s ;  C ->  C* (15.11 MeV  ) MiniDaedalus would be capable of making precision measurements of e appearance &  disappearance and proving, for example, the existence of sterile neutrinos! (see Phys. Rev. D72, 092001 (2005)). For OscSNS & not MiniDAEdALUS

20. Search for Sterile Neutrinos with MiniDAEdALUS (or WC) Via Measurement of NC Reaction:  C ->  C*(15.11) Garvey et al., Phys. Rev. D72 (2005) 092001

21. 21 MiniDAEdALUS e appearance (left) and  disappearance sensitivity (right) for 1 year of running (for 60m!) LSND Best Fit

22. 22 Conclusions The MiniBooNE data are consistent with   e oscillations at  m 2 ~ 1 eV 2 and consistent with the evidence for antineutrino oscillations from LSND. The MiniBooNE   e oscillation allowed region appears to be different from the   e oscillation allowed region. The world antineutrino data fit well to a 3+1 oscillation model with  m 2 ~ 1 eV 2. All 3+N models predict large  disappearance! A MiniBooNE-like detector (MiniDAEdALUS) located ~300’ below the DAEdALUS cyclotron could measure neutrino oscillations with high significance (>>5  ) and prove that sterile neutrinos exist!

23. Backup

24. 24 E>200MeV 5.66E20 POT Oscillations favored over background only hypotheses at 99.6% CL (model dependent) No assumption made about low energy excess Best fit (sin 2 2 ,  m 2 ) = (0.0066, 4.42 eV 2 )  2 /NDF = 20.4/15.3; Prob.=17.1%

25. 25 E>200MeV Subtract excess produced by neutrinos in  mode (11.6 events) E<475MeV: Large background Not relevant for LSND type osc. Big systematics Null  2 =32.8; p=1.7% Best fit (sin 2 2 ,  m 2 ) = (0.0061, 4.42 eV 2 )  2 /NDF = 21.6/15.3; Prob.=13.7%

26. 26 Future sensitivity MiniBooNE approved for a total of 1e21 POT Potential exclusion of null point assuming best fit signal E>475MeV fit Protons on Target

27. 27 BooNE MiniBooNE like detector at 200m Flux, cross section and optical model errors cancel in 200m/500m ratio analysis Present neutrino low energy excess is 6 sigma statistical; 3 sigma when include systematics Study L/E dependence Gain statistics quickly, already have far detector data Near/Far 4  sensitivity similar to single detector 90% CL 6.5e20 Far + 1e20 Near POT Sensitivity (Neutrino mode)

28. 28 BooNE Better sensitivity to     disappearance Look for CPT violation            6.5e20 Far/1e20 Near POT 1e21 Far/1e20 Near POT

29. 29 Reminders of some analysis choices Data bins chosen to be variable width to minimize N bins without sacrificing shape information Technical limitation on N bins used in building syst error covariance matrices with limited statistics MC First step in unblinding revealed a poor chi2 for oscillation fits extending below 475 MeV Region below 475 MeV not important for LSND-like signal -> chose to cut it out and proceed

30. 30 Reminders of some pre-unblinding choices Why is the 300-475 MeV region unimportant? Large backgrounds from mis-ids reduce S/B Many systematics grow at lower energies Most importantly, small S/B so not a good L/E region to look for LSND type oscillations Energy in MB [MeV] 1250 475333

31. 31 E>475 MeV 1 sigma contour includes 0.003<sin 2 2  <1

32. Initial MINOS  Disappearance Results Expect  disappearance above 10 GeV for LSND neutrino oscillations.

33. 33 OscSNS Spallation neutron source at ORNL 1GeV protons on Hg target (1.4MW) Free source of neutrinos Well understood flux of neutrinos Physics reach would be similar with DARDaedalus