June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting The Physics and Status of MiniBooNE Jonathan Link Columbia University Fermilab Annual Users Meeting June 10-11, 2002

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting A Little Neutrino Phenomenology If neutrinos have mass then they may oscillate between flavors with the following probability L is the distance that the neutrino travels (the baseline) E is the neutrino energy sin 2 2  is the oscillation mixing angle  m 2 is the mass difference squared between neutrino mass eigenstates

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting Plenty of Evidence for Neutrino Mass Solar Neutrinos  Recently nailed down by SNO Atmospheric Neutrinos  Super-K, IMB, Kamiokande, etc. LSND  Uncorroborated

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting The LSND Experiment LSND took data from The full dataset represents nearly 49,000 Coulombs of protons on target. Baseline of 30 meters Energy range of 20 to 55 MeV L/E of about 1m/MeV

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting LSND’s Unexpected Result Looked for an excess of e events in a  beam Saw 87.9 ± 22.4 ± 6.0 events over expectation. With an oscillation probability of (0.264 ± ± 0.045)%. 3.3  evidence for oscillation.

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting Why is this Result Interesting? LEP found that there are only 3 light neutrinos that interact weakly. ν3ν3 ν2ν2 ν1ν1 m22m22 m12m12  m 3 2 =  m  m 2 2 Three neutrinos allow only 2 independent  m 2 scales. But we have experimental results in 3  m 2 regions!

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting How Can We Fix the Theory? 1.Add a fourth sterile neutrino. Giving you three independent  m 2 scales. 2.Violate CPT. Giving you different mass scales for and  From Barenboim, et. al., hep-ph If MiniBooNE sees an LSND signal with we can rule this out, but if we don’t then we need to run with  

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting The Other Experiments Allowed Region from Joint Karmen and LSND fit The most restrictive limits come from the Karmen Experiment. From Church, Eitel, Mills, & Steidl hep-ex/ Several other experiments have looked for oscillations in this region.

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting A Conclusive Experiment is Needed With High Significance – At least 5  over the entire LSND region (including systematic and statistical uncertainties) – Demonstrating expected energy dependence for oscillation Low and Different Systematics (Change the signature) – Change the beam to higher energy – Optimize detector for new signature High Statistics – About an order of magnitude more events than LSND

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting BooNE consists of about 60 scientists from 14 institutions. The BooNE Collaboration BooNE was formed to search for e appearance in a  beam at Fermilab. The BooNE Collaboration Y.Liu, I.Stancu University of Alabama, Tuscaloosa S.Koutsoliotas Bucknell University, Lewisburg E.Church, C.Green, G.J.VanDalen University of California, Riverside E.Hawker, R.A.Johnson, J.L.Raaf, N.Suwonjandee University of Cincinnati, Cincinnati T.Hart, E.D.Zimmerman University of Colorado, Boulder L.Bugel, J.M.Conrad, J.Formaggio, J.M.Link, J.Monroe, M.H.Shaevitz, M.Sorel Columbia University, Nevis Labs, Irvington D.Smith Embry Riddle Aeronautical University C.Bhat, S.Brice, B.Brown, B.T.Fleming, R.Ford, F.G.Garcia, P.Kasper, T.Kobilarcik, I.Kourbanis, A.Malensek, W.Marsh, P.Martin, F.Mills, C.Moore, P.J. Nienaber, E.Prebys, A.D.Russell, P.Spentzouris, R.Stefanski, T.William Fermi National Accelerator Laboratory D.C.Cox, J.A.Green, S.McKenney, H.Meyer, R.Tayloe Indiana University, Bloomington G.T.Garvey, W.C.Louis, G.McGregor, G.B.Mills, E.Quealy, V.Sandberg, B.Sapp, R.Schirato, R.Van de Water, D.H.White Los Alamos National Laboratory R.Imlay, W.Metcalf, M.Sung, M.Wascko Louisiana State University, Baton Rouge J.Cao, Y.Liu, B.P.Roe University of Michigan, Ann Arbor A.O.Bazarko, P.D.Meyers, R.B.Patterson, F.C.Shoemaker Princeton University, Princeton The Booster Neutrino Experiment… BooNE

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting The MiniBooNE Neutrino Beam Start with a very intense 8 GeV proton beam from the Booster. The beam is delivered to a 71 cm long Be target. In the target primarily pions are produced, but also some kaons. Charged pions decay almost exclusively as  ±  ±   The decays K ±   e ± e and K L  ± e  e contribute to background. There are also e ’s from muon decay.   e ?

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting The MiniBooNE Beam (Continued) A toroidal field horn focuses the charged particles on the detector. Initially positive particles will be focused selecting, but the horn current can be reversed to select. Increases neutrino intensity by an order of magnitude. The horn is followed by a decay region of 25 m or 50 m. The decay region is followed by an absorber and 500 m of dirt, beyond which only the neutrino component of the beam survives. Switching between 25 m and 50 m decay length helps in understanding the e background from  decay.

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting The MiniBooNE Horn The horn operates at 5 Hz Each 170 kilo-amp (kA) pulse lasts for 150 micro seconds Design lifetime of 200 million pulses (Tested with 10+ million pulses) The horn is designed to maximize neutrino flux from 0.5 GeV to 1 GeV The horn increases neutrino flux at the detector by a factor of 10. MiniBooNE horn during assembly

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting Neutrino Flux at the Detector From beam simulations the expected intrinsic e flux is small compared to the  flux. The L/E is designed to be a good match to LSND at ~1 m/MeV.

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting The MiniBooNE Detector 12 meter diameter sphere Filled with 950,000 liters of pure mineral oil — 20+ meter attenuation length Light tight inner region with 1280 photomultiplier tubes Outer veto region with 240 PMTs. Neutrino interactions in oil produce: Prompt Čerenkov light Delayed scintillation light Čerenkov:scintillation ~ 5:1

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting PMTs at the bottom of the detector just before sealing up the inner region. View of the Veto Region as the first oil is added to the detector. Inside the MiniBooNE Detector

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting Intrinsic e background: 1,500 events  mis-ID background: 500 events  0 mis-ID background: 500 events LSND-based   e : 1,000 events Approximate number of events expected in MiniBooNE with two years of running.

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting Particle ID is based on ring id, track length, ratio of prompt/late light Signatures substantially different from LSND Factor 10 higher energy and baseline Neutron capture does not play a role Fuzzy rings distinguish electrons from muons.  0 from neutral current interactions typically look like 2 electrons, but infrequently the two rings overlap and appear as one. Particle Identification: , e &  0 Ideal Ring

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting Intrinsic Beam Backgrounds – e from  –decay (0.06%) Directly tied to observed  rate Quadratic decay pipe length dependence – e from K–decay (0.06%) Related to observed high E events Beam surveys: BNL-910, HARP “Little Muon Counters” (LMC) Mis-Identification –Neutral current   production (0.1%) Scaled from the 99% that are properly reconstructed –  mis-id’ed as e ’s (0.03%) Scaled from the 99.9% that are properly reconstructed All Backgrounds can be related to data measurements Can change decay pipe length: - n e from m-decay  L 2 - n m from p-decay  L - n e from K + -decay  L <1 Dump 1 Dump 2 Controlling Backgrounds

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting MiniBooNE Sensitivity to LSND With 1  protons on target MiniBooNE should be able to completely include or exclude the entire LSND signal region.

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting Letter of Intent Approved Detector Hall Complete Detector Complete Horn Test Complete First Beam Test Oil Fill Complete Run Begins 5  protons 1  protons Supernova here? First Results: Cross Sections Exotic Searches Oscillations The MiniBooNE Timeline Final Oscillation Result, Including

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting Cosmic Muon Decays Typical  Decay Event Fit Lifetime:  = 2.12 ± 0.05  s P.E. 364 Hits 104 Hits Expected  lifetime in oil  2.13  s with 8%   capture on Carbon. Calibration Study

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting Animation Each frame is 25 ns with 10 ns steps. Early Late Low High Time (Color) Charge (Size) Muon Decay Candidate

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting 12 B decay  decay Supernova MiniBooNE as a Supernova Detector For a Supernova within 10 Kpc we expect to see about 200 interactions in a 10 second period. From Sharp, Beacom and Formaggio hep-ph/ How the supernova signal might look as a function of time.

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting Cross Sections and Exotics Look for things that may not have been conceived of yet Neutrino Magnetic Moment (Very Small in SM) The Karmen Timing Anomaly (see paper by Case, Koutsoliotas and Novak, Phys. Rev. D65:077701, 2002) From Lipari, et al., PRL 74, 4384 The cross sections are not well measured in our energy range. Oscillation probability is small enough that we can ignore it in  cross section measurements.

June 10 & 11, 2002Jonathan Link, Columbia Fermilab Users Meeting Conclusions We expect to begin the run late June/early July. We will take 5  protons on target in  mode (~1 year). With this data we should be able to confirm or rule out the full high  m 2  oscillation range of LSND (CPT conserving). If no signal is seen in mode, running is needed to investigate CPT violation. We are studying several other possible physics topics – Cross Sections – Supernova neutrinos – Exotics Possible upgrade to BooNE, a two detector experiment to carefully measure  m 2 and look for  disappearance.