1 735 km The MINOS Long Baseline Neutrino Oscillation Experiment Jeff Nelson William & Mary Fermilab Users’ Meeting June 6, 2007

2 MINOS Overview >Detector & beam >Oscillation analysis >Neutrino time of flight What’s New? >2 nd year of running >Advances Prospects Argonne Athens Benedictine Brookhaven Caltech Cambridge Campinas Fermilab College de France Harvard IIT Indiana Minnesota-Twin Cities Minnesota-Duluth Oxford Pittsburgh Rutherford Sao Paulo South Carolina Stanford Sussex Texas A&M Texas-Austin Tufts UCL William & Mary Wisconsin

3 MINOS Physics Goals Test the ν μ → ν τ oscillation hypothesis >Measure precisely |Δm 2 32 | & sin 2 2θ 23 PRL 97, (2006) >Search for / constrain exotic phenomena Search for ν μ → ν e oscillations Compare ν, ν oscillations >CPT test Neutrino interaction physics Atmospheric neutrinos >PRD 75, (2007) >PRD 73, (2006) Cosmic rays >hep-ex/ >10 papers to ICRC 2007 See poster by Jeff de Jong Useful Approximations ν μ disappearance (2 flavors): P(ν μ →ν x ) = 1 - sin 2 2θ 23 sin 2 (1.27Δm 2 32 L/E) ν e appearance: P(ν μ →ν e ) ≈ sin 2 θ 23 sin 2 2θ 13 sin 2 (1.27Δm 2 31 L/E) where L, E are experimental parameters & θ 23, θ 13, Δm 2 32 are to be determined Δm 2 32 = m 3 2 – m 2 2 ν1ν1 ν2ν2 ν3ν3 ν1ν1 ν2ν2 ν3ν3

4 Example of a disappearance measurement Look for a deficit of ν μ events at a distance… Unoscillated Oscillated ν μ spectrum Monte Carlo NC background Monte Carlo Spectral ratio NC subtracted eV 2 Unoscillated Oscillated

5 Example of a disappearance measurement Look for a deficit of ν μ events at a distance… Unoscillated Oscillated ν μ spectrum Monte Carlo NC background Monte Carlo Spectral ratio NC subtracted eV 2 Unoscillated Oscillated

6 Example of a disappearance measurement Look for a deficit of ν μ events at a distance… Unoscillated Oscillated ν μ spectrum Monte Carlo NC background Monte Carlo Spectral ratio NC subtracted eV 2 Unoscillated Oscillated

7 Producing the neutrino beam (NuMI) 120 GeV protons strike target >10  s pulse every ~2.4s >Typically running at 2.5e13 protons per pulse 2 magnetic horns focus secondary π/K π/K decays produce neutrinos >Moveable target & horn provides variable beam energy

8 MINOS Detectors Iron and Scintillator tracking calorimeters magnetized steel planes = 1.2T 1×4.1 cm 2 scintillator strips Multi-anode PMT readout GPS time-stamping to synchronize FD data to ND/Beam Main Injector spill times sent to the FD for a beam trigger Far Detector 5.4 kton 8  8  30 m planes Near Detector 1 kton 3.8  4.8  15 m steel planes 153 scintillator planes

9 1pe PMT cross-talk A 2 GeV ν μ event in the far detector Track Energy 2.04 GeV Shower energy 0.20 GeV q/p = ± 0.03 < 2 PE 2 < PE < 20 PE > 20 PE Track hit

10 Energy spectra in ND LE10 pME pHE

11 Energy spectra in ND LE10 pME pHE Data & Nominal MC discrepancy changes energy with beam tune Suggests production of hadrons off the target is to blame

12 Energy spectra in ND LE10 pME pHE Took data in 6 different beam tunes (only 3 shown) Varied the dependence on p T and x

13 MINOS best-fit spectrum for 1.27×10 20 POT Measurement errors are 1 sigma, 1 DOF See poster by Niki Saoulidou PRL 97, (2006) Systematics Δm 2 (10 -3 eV 2 ) sin 2 2θ Near/Far normalization Absolute hadronic scale NC contamination All other systematics Total systematic error

14 MINOS a llowed region for 1.27×10 20 POT Measurement errors are 1 sigma, 1 DOF See poster by Niki Saoulidou PRL 97, (2006)

15 MC Projected MINOS sensitivity Statistical errors 90% C.L.

16 Prospects Neutrino time of flight New data >2 nd year running experience >Post-shutdown intensity Prospects for future >Advancing the oscillation analysis >Electron neutrino appearance >Neutral current >Antineutrinos >Non oscillation physics

17 Neutrino Time of Flight (TOF) PDG limit is >|v−c|/c < 4 × (95% C.L.) >Exotic models predict values all the way up to this limit Separation between the detectors >L = 734,298.6 ± 0.7 m The TOF for a massless particle >τ = s δ = -126 ± 32 (stat) ± 64 (syst.) ns (v−c)/c = [5.1 ± 2.9 (syst. + stat.)] × (68% CL) hepex/ δ (μs)

18 Neutrino Time of Flight (TOF) PDG limit is >|v−c|/c < 4 × (95% C.L.) >Exotic models predict values all the way up to this limit Separation between the detectors >L = 734,298.6 ± 0.7 m The TOF for a massless particle >τ = s δ = -126 ± 32 (stat) ± 64 (syst.) ns (v−c)/c = [5.1 ± 2.9 (syst. + stat.)] × (68% CL) δ (μs) hepex/

19 Relativistic mass measurement Use time and energy to compute a relativistic mass limit >If the neutrino have mass m v its time of flight would be where τ is the TOF for a massless particle We find >The limit is driven by the few points near edge >With full data MINOS dataset ~10 MeV at 99% C.L. Line = 68% C.L. Shaded = 99% C.L. hepex/

20 The 2 nd year of MINOS running 1 st year of running (published dataset) Double dataset Collected with 99.4% live time More !

21 MI intensity improvements: slip stacking MI currently running in “2+5” slip stacking >2 MI bunches for pbar >5 MI bunches for NuMI AD demonstrated “2+9” slip stacking >2 MI bunches for pbar >9 MI bunches for NuMI New record for beam in the MI set in April >4.608 × POT with good transport efficiency >Beam delivery limited to 4.0x10 20 POT until we have a spare target in-hand (this summer) AD plans “2+9” as default after the shutdown

22 How to we plan to exploit this new data? Modeling & reconstruction >Additional data at higher energies >Updated flux model >New hadronization & intranuclear scattering models >Improved reconstruction & PID algorithms Reduce NC systematic errors >Ongoing improvements in calibration Working to extend the oscillation analysis to antineutrinos & higher energies MC

23 Since initial analysis, implemented beam fitting to antineutrinos Antineutrinos come from π - off the target >Rates shown are for normal running conditions Simultaneous neutrino and antineutrino fit >Compared to new p+C data from CERN NA49 Eur.Phys.J.C49: ,2007

24 High energy neutrinos and kaon production Kaons decays tend to produce higher energy neutrinos >MIPP took p+C thin target data at 120- GeV/c MIPP took thick- target data with our NuMI target >Forthcoming K    ratio p T <0.2 GeV/c 0.2<p T <0.4 GeV/c Andre Lebedev, Harvard Ph.D., MIPP-doc-218

25  → e oscillation search See poster by Tingjun Yang 4×10 20 POT 16×10 20 POT P(ν μ →ν e ) ≈ sin 2 θ 23 sin 2 2θ 13 sin 2 (1.27Δm 2 31 L/E)

26 Tuned MC incl. systematic error Neutral current (NC) events NC unaffected by ν μ  ν τ oscillations >Can test for sterile neutrino contributions Near detector NC energy spectrum >Far Detector data for this analysis is still blinded >Currently working on Near/Far extrapolation FD systematic error evaluation

27 Neutrino scattering in the near detector Intense NuMI beam >Recorded 3 ×10 20 POT >5 × 10 6 events in the fiducial volume Can explore new kinematic regions >Connect to precision higher energy experiments Some non-oscillation analyses underway >Total CC differential cross-section >Flux extraction >DIS differential cross-section >Structure functions >Quasi elastic scattering >Coherent production cross-section … MC See poster by Minsuk Kim MC

28 Conclusions Results from the first year of accelerator neutrino exposure >It is consistent with ν μ disappearance with the following parameters >Data also used to measure the TOF and relativistic mass of neutrinos (v−c)/c = (5.1 ± 2.9) × (68% CL, syst. + stat.) More than doubled the dataset since shutdown >Slip stacking offers the prospect of significant intensity improvements after the shutdown New analyses are underway on a number of samples

30 MI intensity improvements with slip stacking MI currently running in “2+5” slip stacking mode >2 MI bunches for pbar >5 MI bunches for NuMI AD demonstrated “2+9” slip stacking mode >2 MI bunches for pbar >9 MI bunches for NuMI New record for beam in the MI set in April >4.608E13 POT with good transport efficiency >Beam delivery limited to 4.0E13 POT until we have a spare target in-hand (this summer) AD plans “2+9” as default after the shutdown >The intensity to be gradually increased from 2.4E13 POT >AD continuing preparations for the MI collimator installation during the shutdown

31 Look for e appearance >P( ν μ → ν e ) ≈ sin 2 θ 23 sin 2 2θ 13 sin 2 (1.27Δm 2 31 L/E) (plus CP violation and matter effects) Look for events with compact shower and typical EM profile >Primary background from NC events >Matter effects alter e yield by  20% Reach depends strongly on POT >Far Detector data for this analysis is still blinded >4×10 20 POT - can challenge the world’s best limit (CHOOZ) >16×10 20 POT - can significantly improve limit and increase chance of discovery  → e oscillation search See poster by Tingjun Yang

32 Tuned MC incl. systematic error Neutral current (NC) events NC interactions >Unaffected by ν μ  ν τ oscillations Can test for sterile neutrino contributions >Large cross-section uncertainty for E ~1 GeV Near detector NC energy spectrum >Far Detector data for this analysis is still blinded >Currently working on Near/Far extrapolation FD systematic error evaluation

33 Neutrino scattering in the near detector Intense NuMI beam offers opportunities for exploring cross- sections >Recorded 3×10 20 POT >We have 5.5×10 6 CC interactions in the fiducial volume Some non-oscillation analyses underway >Total CC differential cross-section >Flux extraction >DIS differential cross-section >Structure functions >Quasi elastic scattering >Coherent production cross-section A few examples of work in progress… MC See poster by Minsuk Kim for more

34 Deep Inelastic Scattering Largest component of the MINOS event sample >The measurement will be systematics limited Can explore new kinematic regions >Connects to precision higher energy experiments MC

35 Quasi elastic scattering (vn → μp) The QE-enhanced sample can be used to extract the flux for M A measurement >3×10 20 POT ~ 800,000 events >Look for Well-defined muon track Low shower energy Low W Main background >Single charged pions