2. Neutrino Physics - Lecture 7 Steve Elliott LANL Staff Member UNM Adjunct Professor 505-665-0068, elliotts@lanl.gov

3. Spring 2007Steve Elliott, UNM seminar series2 Lecture 7 Outline Accelerator Neutrinos - short - medium baseline The neutrinos Past experiments What we know and what we want to learn Most slides from Bill Louis

4. Spring 2007Steve Elliott, UNM seminar series3 The LSND Puzzle and MiniBOONE

5. Spring 2007Steve Elliott, UNM seminar series4 The Evidence for Neutrino Oscillations

6. Spring 2007Steve Elliott, UNM seminar series5 Requires a 3 rd  m 2

7. Spring 2007Steve Elliott, UNM seminar series6 Expt.Type  m 2 (eV 2 ) sin 2 2  LSND   e ~1 ~3x10 -3 Atm.   x ~2x10 -3 ~1 Solar e  x ~8x10 -5 ~0.8 Current State of Neutrino Oscillation Evidence

8. Spring 2007Steve Elliott, UNM seminar series7 MiniBooNE Neutrino Oscillation Update Neutrino Oscillations & the 3  m 2 Problem!?! (Sterile Neutrinos?) MiniBooNE: A Definitive Test of the LSND Neutrino Oscillation Signal Future Neutrino Experiments: BooNE & OscSNS

9. Spring 2007Steve Elliott, UNM seminar series8 3+2 Sterile Neutrinos Sorel, Conrad, & Shaevitz (PRD70(2004)073004) Explain Pulsar Kicks? Explain R-Process in Supernovae? Explain Dark Matter? MaVaNs & 3+1Hung (hep-ph/0010126) Sterile NeutrinoKaplan, Nelson, & Weiner (PRL93(2004)091801) Explain Dark Energy? CPT Violation & 3+1 Barger, Marfatia, & Whisnant (PLB576(2003)303) Sterile NeutrinoExplain Baryon Asymmetry in the Universe? Quantum DecoherenceBarenboim & Mavromatos (PRD70(2004)093015) Lorentz ViolationKostelecky & Mewes (PRD70(2004)076002) Katori, Kostelecky, Tayloe (hep-ph/0606154) Extra DimensionsPas, Pakvasa, & Weiler (PRD72(2005)095017) Sterile Neutrino DecayPalomares-Ruiz, Pascoli, & Schwetz (JHEP509(2005)48) If MiniBooNE Confirms LSND: Physics Beyond the Standard Model & Connections with Astrophysics!

10. Spring 2007Steve Elliott, UNM seminar series9 P  =    i  j  U  i U*  i U*  j U  j  sin 2 (1.27  m ij 2 L/E ) As N increases, the formalism gets rapidly more complicated! N #  m ij 2 #  ij #CP Phases 2 1 10/1 3 2 31/3 6 515 10/15 Probability of Neutrino Oscillations

11. Spring 2007Steve Elliott, UNM seminar series10 MiniBooNE: A Definitive Test of the LSND Evidence for Oscillations: Search for   e Alabama, Bucknell, Cincinnati, Colorado, Columbia, Embry-Riddle, Fermilab, Indiana, Los Alamos, LSU, Michigan, Princeton, St. Mary's, Western Illinois, Yale Completely different systematic errors than LSND Much higher energy than LSND Blind Analysis

12. Spring 2007Steve Elliott, UNM seminar series11

13. Spring 2007Steve Elliott, UNM seminar series12 MiniBooNE Highlights MiniBooNE began taking data in September 2002 and has collected ~750K neutrino events from ~7E20 Protons on Target; Oscillation analysis will use ~600K events from ~5.7E20 POT Experiment is working well (99% livetime & 99% of PMT channels working well) Clearly reconstructing CCQE, CCPI+, NCPI0, & NCEL events First focussing horn was replaced during 2004 fall shutdown after setting a world record of 96M pulses (previous record set at BNL with 13M pulses); Second horn now has >100M pulses Now taking data with Antineutrinos (since January 2006)

14. Spring 2007Steve Elliott, UNM seminar series13 MiniBooNE Neutrino Flux HARP at CERN E910 at BNL

15. Spring 2007Steve Elliott, UNM seminar series14 Expected MiniBooNE Events

16. Spring 2007Steve Elliott, UNM seminar series15 After e PID Selection (from proposal)

17. Spring 2007Steve Elliott, UNM seminar series16 Expected MiniBooNE Sensitivity (from proposal)

18. Spring 2007Steve Elliott, UNM seminar series17 Measurement of Oscillation Parameters (from proposal)

19. Spring 2007Steve Elliott, UNM seminar series18 Likelihoods for Contained NuMI 1 Sub-Events Good agreement between data and MC! Preliminary!

20. Spring 2007Steve Elliott, UNM seminar series19 Backgrounds Non- e Backgrounds Beam Off CC Inclusive NC   NC  N  NC Coherent  NC Radiative  Intrinsic- e Backgrounds From  -> e decay From K-> e decay From  -> e decay

21. Spring 2007Steve Elliott, UNM seminar series20 Beam-Off Background is Negligible! Neutrino Signal to Cosmic-Ray Background ~ 5000 to 1!

22. Spring 2007Steve Elliott, UNM seminar series21 Good PID Agreement for CC Inclusive Events PID CC inclusive events tagged by Michel electrons 92% of   decay 8% of   capture MC is correctly estimating CC inclusive background Preliminary!

23. Spring 2007Steve Elliott, UNM seminar series22 MiniBooNE NC  0 Events are Measured  M  ~ 20 MeV

24. Spring 2007Steve Elliott, UNM seminar series23 Gamma Backgrounds NC  N  BR ~ 0.56% at peak; small but non-negligible background; now properly handled by modified version of NUANCE NC Coherent  Calculated from Rein & Sehgal (Phys. Lett. 104B (1981) 394) & estimated to be negligible NC Radiative  Two sources have been considered, and both are negligible: (1) Bremsstrahlung Term, where  emanates from recoil proton; (2) Contact Term, where  emanates from the interaction vertex

25. Spring 2007Steve Elliott, UNM seminar series24 Intrinsic e Backgrounds From  -> e decay : Well determined from  CCQE events From K-> e decay : Measure kaon-induced neutrino flux at high energies & extrapolate to low energies From  -> e decay : Well determined from  CCQE events

26. Spring 2007Steve Elliott, UNM seminar series25 Expectations for 5E20 Protons on Target Preliminary!

27. Spring 2007Steve Elliott, UNM seminar series26 MiniBooNE Schedule Continue Antineutrino Run Complete Neutrino Oscillation Analysis (Estimate systematic errors from neutrino flux, cross sections, detector MC) Open “Box” and Present Results If MiniBooNE Confirms LSND => Physics Beyond the Standard Model!

28. Spring 2007Steve Elliott, UNM seminar series27 Future Experiments: BooNE & OscSNS What new physics is there Beyond the Standard Model? BooNE would involve a second “MiniBooNE-like” detector (~$8M) at FNAL at a different distance; with 2 detectors, many of the systematics would cancel OscSNS would involve building a “MiniBooNE-like” detector (~$12M) with higher PMT coverage at a distance of ~60 m from the SNS beam stop at ORNL

29. Spring 2007Steve Elliott, UNM seminar series28 BooNE at FNAL Two identical detectors at different distances Search for sterile neutrinos via NCPI0 scattering & NCEL scattering Problem: imprecise energy determination smears oscillations!

30. Spring 2007Steve Elliott, UNM seminar series29 OscSNS at ORNL  -> e  (L/E) ~ 3% ; e p -> e + n  -> s  (L/E)  C*(15.11) OscSNS 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)). Flux shapes are known perfectly and cross sections are known very well. SNS: ~1 GeV, ~1.4 MW

31. Spring 2007Steve Elliott, UNM seminar series30 OscSNS  -> e Experiment vs LSND More Detector Mass (x5) Higher Intensity Neutrino Source (x2) Lower Duty Factor (x100) (less cosmic bkgd) No DIF Background (backward direction) Lower Neutrino Background (x4) (60 m vs 30 m) Better Signal/Background (x4) Better L/E Resolution (x2) (more scint & better PMTs) For LSND parameters, expect ~350 e oscillation events & <50 background events per year! (assuming  m 2 < 1 eV 2 )

32. Spring 2007Steve Elliott, UNM seminar series31 Search for Sterile Neutrinos with OscSNS Via Measurement of NC Reaction:  C ->  C*(15.11) Garvey et al., Phys. Rev. D72 (2005) 092001

33. Spring 2007Steve Elliott, UNM seminar series32 KARMEN Measurement of  C ->   C*(15.11)  NC = (3.2+-0.5+-0.4)x10 -42 cm 2 (B. Armbruster et al., Phys. Lett. B423 (1998) 15)  NC ~2.8x10 -42 cm 2 (Kolbe, Langanke, & Vogel, Nucl. Phys. A652 (1999) 91)

34. Spring 2007Steve Elliott, UNM seminar series33 Measurement of 3+2 Model with OscSNS (Sorel et al., Phys. Rev. D70 (2004) 073004)

35. Spring 2007Steve Elliott, UNM seminar series34 Conclusions MiniBooNE will soon test the LSND Oscillation Signal If the LSND Signal is Confirmed, then Future Oscillation Experiments Would Provide a Great Opportunity for Neutrino Physics: BooNE at FNAL & OscSNS at ORNLMake Precision Measurements of Oscillation Parameters Resolve 3  m 2 Paradox & Explore Physics Beyond the Standard Model! (e.g. Sterile Neutrinos)