MiniBooNE Update Since Last PAC Meeting (Nov 2007) Steve Brice (FNAL) PAC Meeting 27 March 2008

March 2008 PAC MeetingSteve Brice (FNAL)2 CC  + –2 papers expected CC  0 –Reconstruction challenges overcome –1 paper expected NC  0 –1 paper submitted PLB –Coherent/resonant in nu and anti-nu modes –Flux averaged cross-section measurement –2 further papers expected NC Elastic –Flux averaged cross-section measurement –1 paper expected  -e Elastic –Nu mag. Mom –1 paper expected. Oscillation –Refined Nue appearance –Nuebar appearance –Numu and numubar disappearance –1 PRL, ~3 further papers expected Low Energy Excess –Big effort –2+ papers expected Alternative Oscillations –Phenomenology –CP violation, Lorentz violation,... –3+ papers expected NuMI Events –Large event rate from NuMI beam –Check on osc. and Low E –1 paper being written CCQE –1 PRL, 2 further papers expected Broad Range of Analyses No organizational separation between neutrino and anti-neutrino mode 12 PhD Students + 6 graduated = PhD Student (6 already graduated)

March 2008 PAC MeetingSteve Brice (FNAL)3 Publication Update Since Nov 2007 CCQE paper accepted by PRL (Phys. Rev. Lett. 100, (2008))  0 paper submitted to PLB and the archive (arXiv: [hep- ex]) Paper on e background from muon internal Bremsstrahlung submitted to the archive (arXiv: [hep-ex] ) 3 students graduated –D.C. Cox, "A Measurement of the Neutral Current Neutrino-Nucleon Elastic Cross Section at MiniBooNE", PhD Thesis, Indiana University, 2008 –A.A. Aguilar-Arevalo, "An Improved Neutrino Oscillations Analysis of the MiniBooNE Data", PhD Thesis, Columbia University, 2008 –R.B. Patterson, "A Search for Muon Neutrino to Electron Neutrino Oscillations At Δm2 > 0.1 eV2", PhD Thesis, Princeton University, 2007

March 2008 PAC MeetingSteve Brice (FNAL)4 Publications Coming Soon Beam PRD (65 pages) circulating in final draft form Detector NIM (43 pages) circulating in final draft form First draft of combined e analysis paper circulating First draft of combined experiment paper circulating (LSND, MiniBooNE, KARMEN, & Bugey) 4 further analyses in internal review phase

March 2008 PAC MeetingSteve Brice (FNAL)5 Low Energy e Candidates Aiming to have this work completed and presented at Neutrino 2008 (end of May) A great deal of effort gone into studying our background predictions and uncertainties at low energy (below ~475 MeV) Work also on reducing backgrounds at low energy No significant changes expected above 475 MeV

March 2008 PAC MeetingSteve Brice (FNAL)6 Low Energy Changes After a comprehensive review of all the backgrounds to e appearance and their uncertainties Included Photonuclear effect More comprehensive hadronic errors Better handling of beam  + production uncertainties Improved measurement of induced  0 s Better handling of  ± interactions Several modifications to the handling of the background from  0 s Better handling of the radiative decay of the  resonance Arrows indicate whether effect is to increase or decrease the low energy data excess The effects have different magnitudes despite the arrows all being the same size ?

Distance to Wall Backward Cut Evis RED: CCQE Nue BLACK: Background Dirt events tend to be at large radius, heading inward Add a new cut on “DistancetoWall backward” to reduce these. Has significant effect below 475 MeV Big reduction in dirt Some reduction of  0 s Small effect on e s Has almost no effect above 475 MeV shower dirt In low energy region there is a significant background from neutrino interactions in the dirt

Comparing Neutrino/Antineutrino Low Energy e Candidates Green: Effective pi0’s Blue: Dirt Pink: Delta’s Yellow: Other Lt Blue: Nue (CCQE) Neutrino AntiNeutrino The e background breakdown is very similar between neutrino and antineutrino mode running But different hypotheses for the excess can have measurably different effects in the two modes Can compare the two modes to test some of the hypotheses 2.33x10 20 POT E QE

March 2008 PAC MeetingSteve Brice (FNAL)9 The e BDT + e TBL +  CCQE results: Limits from fits to open data 10%-30% improvement in 90% C.L. limit below ~1eV 2. The combination of the three samples gives a increase in coverage in the region  m 2 <1 eV 2. Differences in the details are due to the specific fluctuations in the three data samples and the interplay with correlations among them. The combination yields a consistent result. (A.A. Aguilar-Arevalo) (first draft of paper written)

March 2008 PAC MeetingSteve Brice (FNAL)10 Complete MiniBooNE  Disappearance Sensitivity MiniBooNE data 90% CL sensitivity CDHS CCFR 90% CL Combined analysis with SciBooNE data will significantly improve this sensitivity (K. Mahn)

March 2008 PAC MeetingSteve Brice (FNAL)11 NuMI Data/MC Comparisons  K PRELIMINARY  CCQE sample  CCQE sample MC is normalized to data POT number All  All e PRELIMINARY e CCQE sample e CCQE sample Good agreement between data and Monte Carlo:the MC tuned well. Very different backgrounds compared to MB (Kaons vs Pions) Ongoing effort to reduce e e CCQE sample systematics (Z. Djurcic)

Phys. Lett. 100, (2008) arXiv: ; submitted to Phys.Lett. B NuInt07, D.C. Cox, Ph.D. thesis, IU (2008) Neutrino Cross Sections PAC (Mar 2008) NuInt07, results soon

March 2008 PAC MeetingSteve Brice (FNAL)13  CCQE published in PRL earlier this year (100, , 2008) (T. Katori) before fit after fit yields stunning data/Fermi Gas model agreement across entire phase space ! QE 2 parameter fit (M A QE =1.23  0.20 GeV,  =1.019  0.011) in Q 2 T  (GeV)

March 2008 PAC MeetingSteve Brice (FNAL)14  NC Elastic NC EL Results (from 10% nu sample): - NC elastic diff. cross section (per nucleon, n+p averaged, flux averaged) - Flux Integrated Cross-Section = 8.8 ±0.6(stat) ±2.0(syst) x cm 2 - Measured axial mass (NC) = –0.25 GeV - work of Chris Cox, Indiana U., Ph.D further analysis on full nu data set and with goal of reducing systematic errors in progress (D. Perevalov, Alabama) - eventual analysis goal: NC/CCQE ratio measurement and antinu data (D.C. Cox)

March 2008 PAC MeetingSteve Brice (FNAL)15   NC  0 largest  NC  0 sample ever collected! Rein-Sehgal prediction coherent  0 fraction = (19.5  2.7)%; MC prediction = 30% arXiv: , submitted to Phy. Lett. B, March ,600  0 events  m  ~ 20 MeV/c 2 (J. Link) NC  0 Cross-section x flux MB result

March 2008 PAC MeetingSteve Brice (FNAL)16 developed a new 3-ring fitter (  +  ) for this new   analysis (R. Nelson) preliminary   CC  0 provides a means to test a pure resonant single-  sample (w/ no coherent  contribution) 31,755 events CC  0

PAC (Nov 2007) Moriond EW (March 2008) PAC (Nov 2007) PAC (Mar 2008) Antineutrino Cross Sections

March 2008 PAC MeetingSteve Brice (FNAL)18  NC  0 shown at Moriond earlier this month 1,744 events (plus, will be taking more data in mode soon) (V. Nguyen) NC  0

March 2008 PAC MeetingSteve Brice (FNAL)19 direct way to check predicted rate and energy dependence of backgrounds in mode (J. Nowak) as well as most forward  + production (outside HARP data) HARP (absolutely normalized) CC  +  CC  + in Mode E (GeV)

March 2008 PAC MeetingSteve Brice (FNAL)20 Future Run Plan Current amount of antineutrino data -Blue line is historical running with NuMI on and slip stacking. -Green line is what we might get with RF load resistor upgrade (parts are being acquired). Next shutdown is Spring 2009