A Letter of Intent to Build a MiniBooNE Near Detector: BooNE W.C. Louis & G.B. Mills, FNAL PAC, November 13, 2009

1. A Letter of Intent to Build a MiniBooNE Near Detector: BooNE W.C. Louis & G.B. Mills, FNAL PAC, November 13, 2009 Louis BooNE Physics Goals MiniBooNE Appearance & Disappearance Results Global 3+1 Fits to World Data Preliminary MINOS Results Mills BooNE (New Detector or Moving MiniBooNE) Appearance Sensitivities Disappearance Sensitivities Conclusions

2. BooNE Physics Goals 1. Search for ne & ne appearance and nm & nm disappearance with high sensitivity at ~1 eV2 mass scale. 2. Search for differences between neutrinos & antineutrinos (CP & CPT violation). 3. Search for sterile neutrinos by comparing NCp0 interactions. 4. Determine whether the MiniBooNE neutrino low-energy excess is due to oscillations or to a new background of importance to NOvA and LBNE. 5. Determine whether there is large nm disappearance, as suggested by global 3+1 fits to world antineutrino data. 6. Determine whether there is ne appearance consistent with LSND.

3. P(nm ne)= sin22q sin2(1.27Dm2L/E) target and horn decay region absorber dirt detector nm ne??? K+ p+ Booster primary beam secondary beam tertiary beam (protons) (mesons) (neutrinos) MiniBooNE’s Design Strategy Keep L/E same as LSND while changing systematics, energy & event signature Order of magnitude longer baseline (~500 m) than LSND (~30 m) Order of magnitude higher energy (~500 MeV) than LSND (~30 MeV)

4. MiniBooNE ne appearance data show a low-energy excess A.A. Aguilar-Arevalo et al., PRL 102, 101802 (2009) Excess from 200-475 MeV = 128.8+-20.4+-38.3 events 6.46E20 POT

5. Backgrounds: Order (G2as) , single photon FS N’  N N’   N   Axial Anomaly  Other PCAC N’ N   N N’  Dominant process accounted for in MC! (G2S)   Radiative Delta Decay So far no one has found a NC process to account for the , difference & the n low-energy excess. Work is in progress: R. Hill, arXiv:0905.0291 Jenkins & Goldman, arXiv:0906.0984

6. MiniBooNE ne appearance data are inconclusive at present but are consistent so far with LSND Excess from 200-475 MeV = 11.4 ± 9.4 ±11.2 events Preliminary for 4.863E20 POT (~50% increase in POT!) New!

7. Preliminary ne Data with 4.863 E20 POT En>200 MeV En>475 MeV Data Events 225 126 Bkgd Events 201.6 114.1 Excess Events 23.4+-22.6 11.9+-16.4 Excess at b.f. 41.6+-23.4 (1.78s) 32.2+-16.8 (1.92s) LSND Expect. ~29.7 ~21.8 c2null 32.3/18 DF (2%) 27.5/15 DF (2%) c2bf 21.8/16 DF (15%) 18.4/13 DF (14%) Dm2bf 4.42 eV2 4.64 eV2 sin22qbf0.0058 0.0058 Event excess has increased with new data. Additional data will double #POT and determine whether this excess is real.

8. 3+1 Global Fit to World Antineutrino Data (without new antineutrino data) G. Karagiorgi et al., arXiv:0906.1997 Best 3+1 Fit: Dm412 = 0.915 eV2 sin22qme = 0.0043 c2 = 87.9/103 DOF Prob. = 86% Predicts nm &ne disappearance of sin22qmm ~ 35% and sin22qee ~ 4.3%

9. 3+1 Global Fit to World Antineutrino Data w/o LSND

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

11. Initial MINOSnmDisappearance Results Expect nm disappearance above 10 GeV for LSND neutrino oscillations.

12. Conclusion • MiniBooNE observes an unexplained excess at low energies, which could be due to n oscillations, sterile n decay, or to NCg scattering. No large low-energy excess is observed so far in antineutrino mode. • All antineutrino data fit well to a simple 3+1 model. (LSND is alive & well!) However, there is tension between neutrino & antineutrino data. (CPT Violation?) • The global fit to the world antineutrino data predicts large nm disappearance, which will be tested soon by MINOS and SciBooNE/MiniBooNE. • BooNE, which involves building a near MiniBooNE detector, will be able to exploit the data taken in the far detector (the hard part!) and determine whether there is large nm disappearance and whether the MiniBooNE low-energy excess is due to n oscillations. • Thorough understanding of this short-baseline physics is of great importance to long-baseline n oscillation experiments. BooNE would be a small investment to ensure their success!

13. BooNEA near detector at 200 meters from the BNB target • Reduce low-energy excess systematic errors in Near/Far comparison • potential 6 sensitivity from statistical errors: 12820(stat)38(sys) • Accumulate neutrino and antineutrino data at x7 rate! • Full samples in ~1 year (2 x 1x1020pot) • Capitalize on the 10 year investment in MiniBooNE data • Determine L/E dependence of low energy excess • Search with high sensitivity for ne & ne appearance and nm & nmdisappearance • Special runs to check systematic effects (absorber down, horn off, etc.)

14. New Location at 200 meters from BNB Target Far Position BNB beam Near Position BNB Target Hall

15. The MiniBooNE Low-Energy Excess with BooNE Background case: the near detector will observe the same fractional excess as the far detector Neutrino oscillations at low Dm2: the near detector will observe no excess and the excess in the far detector, assuming a 2.5% systematic error, will be: (in a nutshell) 128.8+-20.4+-38.3 (3.0 s) (current MiniBooNE measurement) 128.8+-28.8+-10.4 (4.2 s) (near/far comparison with 1x1020pot @ ND) 128.8+-20.4+-10.4 (5.6 s) (with >> 1x1020pot @ ND)

16. Neutrino Fluxes at Near and Far Locations

17. µ Charged Current QE Event Rates Near and Far Quasi elastic event rates

18. ne Appearance Sensitivity with Near/Far Comparison • Near/Far comparison sensitivity • Near location at 200 meter • 1x1020 pot <1 yr of running • Full systematic error analysis • Flux, cross section, detector response • Assumes identical detectors in Near/Far comparison Near/Far 4  sensitivity similar to single detector 90% CL

19. ne Appearance Sensitivity with Near/Far Comparison • Near/Far comparison sensitivity • Near location at 200 meter • 1x1021 pot for FD • 1x1020 pot <1 yr for ND • Full systematic error analysis • Flux, cross section, detector response • Assumes identical detectors in Near/Far comparison

20. µ and µ Disappearance Sensitivity with Near/Far Comparison With two identical detectors, many of the systematic errors will cancel, giving excellent disappearance sensitivity *

21. BooNE Disappearance Discovery Potential Allowed region for signal: Dm2 =0.915 eV2 and sin22qmm=0.35 (after G. Karagiorgi et al., arXiv:0906.1997)

22. Options for Near BooNE Detector • New Detector (two detectors run concurrently) • Construct brand new detector at 200 meters (~8M$) • Move old detector • Transport existing MiniBooNE detector (~80 tons) to new location 200 meters from BNB target (~4M$) • OR Dismantle existing MiniBooNE detector, reuse PMTs and electronics to construct a new detector at 200 meters. (~4M$) • MicroBooNE could reduce it’s costs by using the MiniBooNE enclosure 22

23. BNB Beam Stability • The MiniBooNE neutrino rate per pot has been exceptionally stable • horn and target changed in 2004 • polarity changed in 2005, 2007, and 2008

24. BooNE is Complementary to MicroBooNE & SciBooNE • MicroBooNE will determine whether the MiniBooNE low-energy • is due to electrons or gammas • MicroBooNE will not be able to determine the L/E dependence • of the low-energy excess or search for disappearance • MicroBooNE statistics will be too low for antineutrino • appearance • SciBooNE/MiniBooNE joint analysis will make an initial search • for disappearance with two detectors; however, the statistical & • systematic error will be much larger than BooNE • SciBooNE/MiniBooNE will not be able to improve the search • for appearance

25. Conclusion A BooNE near detector at 200 meters with one year of running would resolve whether or not the low-energy n excess is due to an oscillation-like phenomena at the ~ 4 sigma level It would also provide a high statistics, low systematic error µ and µ disappearance measurement in a region not yet covered by other experiments The timing of the project is ideal for post-antineutrino running in the BNB We are studying whether it is better to move the existing detector or to construct a new one (cost vs. performance)

26. Backup Slides

27. MiniBooNE ne appearance data are inconclusive at present but are consistent so far with LSND A.A. Aguilar-Arevalo et al.,PRL 103, 111801 (2009) Excess from 200-475 MeV = -0.5 ± 7.8 ± 8.7 events 3.4E20 POT

28. MiniBooNE ne appearance sensitivity

29. MiniBooNE ne appearance data are inconclusive at present but are consistent so far with LSND Excess from 200-475 MeV = 10.2 ± 15.8 events Preliminary for 4.863E20 POT

30. Preliminary ne Fits with 4.863 E20 POT En>200 MeV En>475 MeV LSND allowed region LSND allowed region

31. BooNE Rough Cost & Schedule Estimate Common costs whether building or moving (FY10-FY11) New Hall Engineering & Construction* $1894K Moving MiniBooNE: (FY10-FY12) Engineering and Transport $1500K Superstructure Removal $500k Total $3894K New Detector (FY10-FY13) Tank & Support Structure * $1065K PMTs $1759K Electronics/DAQ $512K Oil $1429K Calibrations + Miscellaneous $610K Total $7269K *MiniBooNE costs + 3%/year+30%contingency, no G&A or DOE “project costs”

32. BooNE Appearance Sensitivity ne Appearance Sensitivity ne Appearance Sensitivity

33. 3+1 Global Fit to World Neutrino Data G. Karagiorgi et al., arXiv:0906.1997 Best 3+1 Fit: Dm412 = 0.19 eV2 sin22qme = 0.031 c2 = 90.5/90 DOF Prob. = 46% Predicts nm &ne disappearance of sin22qmm ~ 3.1% and sin22qee ~ 3.4%

34. With oil removed, MiniBooNE is about 80 tons: Lift of 260 ton Generator 750 ton crane Transporting 550 ton Coker Drum from ship to crane hook 34