Neutrino Oscillations at the Atmospheric Scale Jeff Hartnell

Neutrino Oscillations at the Atmospheric Scale Jeff Hartnell Rutherford Appleton Laboratory One-day Io. P/Cf. FP Meeting on Neutrinos 29 th June 2005 Jeff Hartnell, Io. P/Cf. FP Meeting

Talk Outline n n n Neutrino oscillation formulism Production of Atmospheric Neutrinos State-of-the-art: ¡ ¡ n Super-Kamiokande K 2 K New Experiments: ¡ MINOS n n ¡ Beam Neutrinos Atmospheric Neutrinos Opera/Icarus Jeff Hartnell, Io. P/Cf. FP Meeting

Neutrino Oscillation Formulism n Disappearance experiments ¡ n Look for neutrinos missing at particular energies (E) and distances (L) Appearance experiments ¡ Look for neutrinos of a particular flavour not present at the source possibly as L/E Jeff Hartnell, Io. P/Cf. FP Meeting

Production of Atmospheric Neutrinos Jeff Hartnell, Io. P/Cf. FP Meeting

Super-Kamiokande n n n Located in Kamioka, Japan 50 k. T water Cerenkov detector (22. 5 k. T fiducial) ~12000 PMTs Overburden of 2700 mwe Separate muons and electrons by Cerenkov ring structure Jeff Hartnell, Io. P/Cf. FP Meeting

Super-K Flavour Separation e m- Jeff Hartnell, Io. P/Cf. FP Meeting

Latest Super-K Zenith Angle Results OD Up Down OD New finer binned analysis and new distributions Jeff Hartnell, Io. P/Cf. FP Meeting

L/E Analysis (2004) n Select high L/E resolution events ¡ n Can better constrain Δm 223 “See” the dip? Best fit region of Δm 223. Jeff Hartnell, Io. P/Cf. FP Meeting Oscillatory Dip

Super-K Parameter Space Latest zenith angle results Allowed regions lie between (old) zenith and L/E results Best fit: Dm 2 = 2. 5 x 10 -3 e. V 2 sin 2(2 q) = 1. 0 Has shifted up! (old) Jeff Hartnell, Io. P/Cf. FP Meeting

K 2 K (KEK to Kamioka) n n n Neutrinos from KEK accelerator Uses Super-K as Far detector, 250 km baseline 2 Near detectors: ¡ ¡ Water Cerenkov “Sci. Bar” scintillator detector Jeff Hartnell, Io. P/Cf. FP Meeting

K 2 K Results (149. 7 expected) Shape comparison Confirmation of Super-K Δm 223 results Jeff Hartnell, Io. P/Cf. FP Meeting

Challenges ahead n n n Clearly “see” the oscillatory signature Show νμ → ντ rather than νμ → νx Precisely measure Δm 223 Determine if sin 2(2θ 23) is maximal Measure sub-dominant oscillation mode: νμ → νe (determine θ 13) CP Violation… see later talks Jeff Hartnell, Io. P/Cf. FP Meeting

New/Current Accelerator Experiments n Nu. MI (Neutrinos at the Main Injector) ¡ Currently operating n n n ¡ ¡ ¡ n First neutrinos seen in January Operations started in March Currently delivered ~1. 2 x 1019 pot total Experiment: MINOS Future Experiments: Minerva, NOv. A Neutrino test-beam (!) for Opera CNGS (CERN Neutrinos to Gran Sasso) ¡ ¡ Due to switch on in Summer 2006 Experiments: Opera and Icarus Jeff Hartnell, Io. P/Cf. FP Meeting

The Nu. MI Beam n Currently: ¡ ¡ ¡ n Running in the low-energy configuration Delivering ~1. 9 x 1013 protons per 10 usec pulse Cycle time of 2 -4 secs Goal: ¡ 3. 7 x 1013 ppp every 1. 9 secs Jeff Hartnell, Io. P/Cf. FP Meeting

MINOS n n 735 km baseline Two magnetised iron-scintillator tracking calorimeters ¡ ¡ Near detector at Fermilab Far detector at Soudan Underground Lab. Near Detector: 980 tons Det. 1 Far Detector: 5400 tons 735 km Jeff Hartnell, Io. P/Cf. FP Meeting Det. 2

The MINOS Detectors Near Detector, 980 tons n Far Detector, 5400 tons Identical in important features: ¡ ¡ ¡ 2. 54 cm thick steel planes 1 cm thick scintillator planes 1. 5 T magnetic field Jeff Hartnell, Io. P/Cf. FP Meeting

Start data taking Target leak Commissioning of the neutrino beam Commissioning of the primary proton beam § In order to understand the systematic of neutrino production and detector response have run with different beam energies (LE, p. ME, p. HE) Jeff Hartnell, Io. P/Cf. FP Meeting

Consider High-energy Data Set n n n 1. 7 x 1018 pot ~150000 spills In the Far detector: ¡ ¡ ¡ 21 charged-current-like events (contain a track) 9 neutrino-induced rock muons 6 cosmic muons (expected 7) Jeff Hartnell, Io. P/Cf. FP Meeting

Far det. High-energy Event 2 D: U-Z Projection 2 D: V-Z Projection ~2. 5 Ge. V muon ~5 Ge. V shower U and V axes tilted at 45 deg to X and Y Jeff Hartnell, Io. P/Cf. FP Meeting End-on view

Beam event separation (Far) (N. Saoulidou) Jeff Hartnell, Io. P/Cf. FP Meeting

MINOS Atmospheric Neutrinos (Preliminary results) n n ~7 k. T-years of data Recorded 107 events See hints of zenith angle dependence Also: first deep underground detector that can resolve muon charge: ¡ ¡ N+ / (N+ + N-) = 0. 35 ± 0. 06 (stat. ) ± 0. 02 (syst. ) Expect: N+ / (N+ + N-) = 0. 35 with CPT invariance Jeff Hartnell, Io. P/Cf. FP Meeting

MINOS Time-line n Collect 1 x 1020 protons on target (pot) by the end of the year ¡ n n n Sensitivity ~= SK / K 2 K results Ramp up beam intensity next year to ~2. 5 x 1020 pot/year Then up to 3. 7 x 1020 pot/year Run for 5 years Jeff Hartnell, Io. P/Cf. FP Meeting MINOS sensitivity by the end of 2005 (~1 e 20 pot)

Sensitivity with 16 e 20 pot (~5 yr) See the dip and the rise “smoking gun” for neutrino oscillations Jeff Hartnell, Io. P/Cf. FP Meeting Significantly constrain Δm 223 to 10% at 90% CL

MINOS Sensitivity to νe Appearance n Look for subdominant oscillation modes: ¡ n 3 sensitivity plot νμ → νe (θ 13) Achieve a factor of 2 -3 over CHOOZ limit in 3 -5 years at 3 sigma Jeff Hartnell, Io. P/Cf. FP Meeting SK

CNGS: Opera and Icarus n n n Baseline: 730 km <Eν> = 17 Ge. V optimised for τ appearance Icarus is a liquid argon TPC with very high spatial resolution Can do lots of physics: beam tau appearance, electron appearance, solar & atmospheric neutrinos, supernova neutrinos, proton decay… Focus on Opera in this talk Jeff Hartnell, Io. P/Cf. FP Meeting

Opera n The “Brick” - Emulsion Cloud Chamber ¡ ¡ n Pb / emulsion layers Look for kinks in tracks Electronic detectors (scint. , RPCs, Drift tubes): ¡ ¡ triggering and localisation of events Muon ID and momentum 1 mm 10 X 0 t n 8. 3 kg Pb Emulsion layers Jeff Hartnell, Io. P/Cf. FP Meeting

Opera Sensitivity (full mixing, 5 years run @ 4. 5 x 1019 pot / year) OPERA signal (Dm 2 = 1. 9 x 10 -3 e. V 2) (Dm 2 = 2. 4 x 10 -3 e. V 2) (Dm 2 = 3. 0 x 10 -3 e. V 2) 6. 6 10. 5 16. 4 BKGD 0. 7 1. 8 kton fiducial n n Looking for a small number of events Very dependent on Δm 223 Probability of observing in 5 years a number of candidates greater than a 4 background fluctuation Jeff Hartnell, Io. P/Cf. FP Meeting D. Autiero (Neutrino ’ 04)

Summary-to-date n It’s now 40 years since the first atmospheric neutrinos were detected and a lot has happened since: ¡ ¡ n Deficit of muon neutrinos discovered Zenith angle dependence shown SK L / E analysis shows possible oscillatory dependence K 2 K observes νμ disappearance and a spectral distortion using accelerator neutrinos The latest (fine binned) SK analysis gives: ¡ ¡ 2. 0 x 10 -3 < Δm 223 < 3. 0 x 10 -3 e. V 2 at 90% CL (~40% range) 0. 93 < sin 2(2θ 23) < 1. 0 at 90% CL (~7% range) Jeff Hartnell, Io. P/Cf. FP Meeting

Challenges ahead (the roadmap) n Confirm SK and K 2 K allowed region ¡ n Clearly “see” the oscillatory signature ¡ n Opera/Icarus (~2011) Precisely measure Δm 223 ¡ ¡ n MINOS (~2010) Show νμ → ντ rather than νμ → νx ¡ n MINOS (~2006) Note: all these results depend on #pot delivered and the value of Δm 223 and sin 2(2θ 23) MINOS: 10% (~2008) NOv. A / T 2 K: 3% (~2015) (see Gary Barker’s talk) Determine if sin 2(2θ 23) is maximal NOv. A / T 2 K: 1% (~2015) Sub-dominant mode, νe appearance (θ 13) ¡ MINOS: Factor of 2 over CHOOZ (~2010) ¡ NOv. A / T 2 K: ~order of magnitude better (~2015) ¡ n n CP Violation… neutrino factory / super beams? Jeff Hartnell, Io. P/Cf. FP Meeting

Backup slides Jeff Hartnell, Io. P/Cf. FP Meeting

Jeff Hartnell, Io. P/Cf. FP Meeting

Opera m spectrometer Magnetised Iron Dipoles Drift tubes and RPCs nt Target: - a “wall” of Pb/emulsion “bricks” - planes of orthogonal scintillator strips Jeff Hartnell, Io. P/Cf. FP Meeting

Future Experiment: NOv. A n n n 15 mrad off-axis in the Nu. MI beam 30 k. Ton Totally Active Scintillator Design 810 km baseline Stage 1 approval from Fermilab and R&D money Aim to have 5 k. T by early 2010 and complete detector by mid-2011. Physics: ¡ ¡ Measure Δm 223 to 2 -4% at 90% CL Quasi-elastic events very clean: n n Measure sin 2(2θ 23) to 0. 5 -3% at 90% CL For details on sensitivity to θ 13, CPV and mass hierarchy see Gary Barker’s talk Jeff Hartnell, Io. P/Cf. FP Meeting

NOv. A Sensitivities 5 -year n run with Proton Driver Jeff Hartnell, Io. P/Cf. FP Meeting

Future Exp. : T 2 K (Tokai to Kamioka) n n n J-PARC accelerator facility in Tokai Use SK detector as with K 2 K ~45 mrad off-axis (2. 5 deg) 295 km baseline Start physics running in 2009 Similar sensitivity to NOv. A on atmospheric scale parameters: ¡ ¡ n Measure sin 2(2θ 23) to 1 -2% Measure Δm 223 to 2 -4% at 90% CL As with NOv. A, for details on θ 13, CPV and mass hierarchy see Gary Barker’s talk Jeff Hartnell, Io. P/Cf. FP Meeting

Brief History of Atmospheric Neutrino Measurements n First detected, via neutrino-induced muons, in 1965 (very deep: ~3 km, ~8000 mwe) ¡ ¡ n First fully contained events in early 1980 s ¡ n Kolar gold fields in S. India East Rand Proprietry mine in S. Africa Proton decay experiments (a background!) First hint of atmospheric anomaly in 1986 ¡ IMB proton decay experiment noticed a deficit in events with an identifiable muon decay: n n n In 1988 the Kamiokande experiment went further and suggested that neutrino oscillations could be the cause of the deficit ¡ n n Measured N (νμ) / NTotal = 26% ± 3% Expected 34% ± 1% Determined R’ = 0. 59 ± 0. 07 (stat. ) Fine-grained iron calorimeters NUSEX and Frejus experiments reported no deficit within statistical errors but Soudan-2 did In 1998 the breakthrough came with Super-Kamiokande… Jeff Hartnell, Io. P/Cf. FP Meeting

Jeff Hartnell, Io. P/Cf. FP Meeting

Finer-Binned 2 -Flavor Analysis Preliminary Combine advantages of standard and L/E analyses - PC events divided into OD stop/OD through-going - New FC multi-ring e-like category - Finer m-like momentum binning; coarser e-like momentum binning Total of 370 bins in zenith angle, momentum c 2 incorporates Poissonian uncertainties Jeff Hartnell, Io. P/Cf. FP Meeting

Allowed regions for the various subsamples 370 bin analysis 180 bin analysis Preliminary Finer binning for multi-Ge. V, PC, multi-ring improves the Dm 2 constraint Jeff Hartnell, Io. P/Cf. FP Meeting