Neutrino Oscillation Experiments – Past, Near Future, T2K Dave Wark
advertisement
Neutrino Oscillation Experiments – Past, Near Future, T2K Dave Wark Imperial/RAL Higgs-Maxwell Edinburgh Feb. 9, 2005 F ebrua ry , 2004 11 Higgs-Maxwell Feb. 9 Never ’05 begin a talk with an excuse or an apology …so sorry about this, but I can’t really do my job properly, and it isn’t my fault. Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 Never ’05 begin a talk with an excuse or an apology …so sorry about this, but I can’t really do my job properly, and it isn’t my fault. Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Articles in hep-ex, hep-ph, or hep-th in past year (to 24/8/03) with word in title structure 211 gluon 109 107 Quark 443 CP 201 Standard model QCD 442 spin 191 SUSY 97 String 435 fermion 166 LHC 83 Brane 325 lepton 163 unification 75 Higgs 288 photon 135 Linear collider 59 Meson 284 inflation 117 strong 58 perturbation 213 electroweak 109 flavour 42 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Articles in hep-ex, hep-ph, or hep-th in past year (to 24/8/03) with word in title Neutrino Quark 558 443 structure 211 gluon 109 CP 201 Standard model 107 QCD 442 spin 191 SUSY 97 String 435 fermion 166 LHC 83 Brane 325 lepton 163 unification 75 Higgs 288 photon 135 Linear collider 59 Meson 284 inflation 117 strong 58 perturbation 213 electroweak 109 flavor 136 Cannot possibly cover the field in one talk Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Solar Neutrinos Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Next three plots adapted from http://www.sns.ias.edu/~jnb/ Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 71±5 71±5 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Before the SM was even formalized the theorists were thinking…. • 1957 – Bruno Pontecorvo, wondering if there are any other particles — which could undergo oscillations analogous to K0 K0 oscillations, hit upon the idea of neutrino anti-neutrino oscillations (more about this later). • 1962 – Maki, Nakagawa, and Sakata (in the context of what looks today like a very odd model of nucleons) proposed that the weak neutrinos known at the time were superpositions of “true” neutrinos with definite masses, and that this could lead to transitions between the different weak neutrino states. • 1967 – Pontecorvo then considered the effects of all different types of oscillations in light of what was then known, and pointed out before any results from the Davis experiment were known that the rate in that experiment could be expected to be reduced by a factor of two! • 1972 – Pontecorvo is informed by John Bahcall that Davis does indeed see a reduced rate, and responds with a letter…. Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Neutrino Oscillations • If neutrinos have mass, then there are two distinct types of neutrino state we must consider – the eigenstates of the weak Hamiltonian nl = ne, nm, nt; and the eigenstates of the free particle Hamiltonian ni = n1, n2, n3. • There is absolutely no reason to believe that these are the same thing. • In general: n l Uli n i Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 If neutrinos have mass: ’05 n l Uli n i For three neutrinos: U e1 U e2 U li Uμ1 Uμ2 U τ1 U τ2 U e3 1 0 0 c13 0 s13eiδ c12 s12 0 Uμ3 0 c23 s23 0 1 0 s12 c12 0 iδ U τ3 0 s23 c23 s13e 0 c13 0 0 1 where cij cos ij , and sij sin ij Three Angles 2 Δm L 2 2 P(ν μ νe ) sin 2θ sin ( 1.27 ) E Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 If neutrinos have mass: ’05 n l Uli n i For three neutrinos: U e1 U e2 U li Uμ1 Uμ2 U τ1 U τ2 U e3 1 0 0 c13 0 s13eiδ c12 s12 0 Uμ3 0 c23 s23 0 1 0 s12 c12 0 iδ U τ3 0 s23 c23 s13e 0 c13 0 0 1 where cij cos ij , and sij sin ij Two mass differences - each has a sign 2 Δm L 2 2 P(ν μ νe ) sin 2θ sin ( 1.27 ) E sin 2 sin 2 m 2 2 ( cos 2 )2 sin 2 2 2 2GF N e E / m 2 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 If neutrinos have mass: ’05 n l Uli n i For three neutrinos: U e1 U e2 U li Uμ1 Uμ2 U τ1 U τ2 U e3 1 0 0 c13 0 s13eiδ c12 s12 0 Uμ3 0 c23 s23 0 1 0 s12 c12 0 iδ U τ3 0 s23 c23 s13e 0 c13 0 0 1 where cij cos ij , and sij sin ij CP violating phase! 2 Δm L 2 2 P(ν μ νe ) sin 2θ sin ( 1.27 ) E Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 The Super-Kamiokande Detector Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 nm produces a m, which produces a sharp ring m e ne produces an electron, which produces a “fuzzy” ring Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 SK ’05 data as a function of zenith angle Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 1000 tonnes D2O Surface: 2 km Phototube Support Structure (PSUP) Acrylic Vessel 104 8” PMTs 6500 tonnes H2O Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 2 tons of NaCl added to D2O on June 1, 2001 s = 0.0005 b s = 44 b 35Cl+n 8.6 MeV 2H+n 6.0 MeV 3H 36Cl Dave Wark University of Sussex/RAL Higgs-Maxwell 2 tons of NaCl added to D2O on June 1, 2001 Feb. 9 ’05 Results from 254.2 live days of data taken between July 26, 2001 and October 10, 2002 s = 0.0005 b s = 44 b 35Cl+n 8.6 MeV 2H+n 6.0 MeV 3H 36Cl Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 • Blind Analysis Technique Used Unknown fraction of muon followers included in data set for analysis • NC cross-section “spoiled” in Monte Carlo • Data pre-scaled by unknown 80±10% Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 Comparison of pure D2O and Salt results ’05 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 KamLAND Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 1st KamLAND Results … K. Eguchi et al., hep-ex/0212021 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 1st KamLAND Results … K. Eguchi et al., hep-ex/0212021 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 What does this mean about solar n? Observed/Expected = 0.611 ± 0.085(stat.) ± 0.041(syst.) Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 What does this mean about solar n? Observed/Expected = 0.611 ± 0.085(stat.) ± 0.041(syst.) Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 If neutrinos have mass: ’05 n l Uli n i For three neutrinos: U e1 U e2 U li Uμ1 Uμ2 U τ1 U τ2 U e3 1 0 0 c13 0 s13eiδ c12 s12 0 Uμ3 0 c23 s23 0 1 0 s12 c12 0 iδ U τ3 0 s23 c23 s13e 0 c13 0 0 1 where cij cos ij , and sij sin ij LSND 2 Δm L 2 2 P(ν μ νe ) sin 2θ sin ( 1.27 ) E Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Parameters needed to specify model •Three Angles – 12 , 23 , 13 •Two mass differences – m212 , m223 •Two signs of the mass differences •One Dirac CP phase But Also: •The absolute mass scale •Are neutrinos Dirac or Majorana (or both)? •Two Majorana CP phases •Are there more - sterile - neutrinos (neuterinos)? •Are there any surprises??? Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Measuring 23 and m223 • Atmospheric Neutrinos • Long-Baseline Accelerator Neutrino Experiments Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Measuring 23 and m223 • Atmospheric Neutrinos • Long-Baseline Accelerator Neutrino Experiments – – – – K2K MINOS OPERA ICARUS Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 The ’05 first LBL Experiment – K2K Dave Wark University of Sussex/RAL IMFP03 Feb. 25 CHEP ’03 ’02 Dave Wark University of Sussex/R Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Evidence for n oscillations from K2K Dave Wark University of Sussex/RAL The MINOS Experiment Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 MINOS Sensitivity in 5 year run Current SK region Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 Beam ’05 construction is well advanced, first beams in 2006 nt ? Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 OPERA Detector: Emulsion ~2 kTon (Pb) 0.04 kTon emulsion Plastic base 1 mm t n Pb 56 emulsion films / brick • To the full detector: 2 supermodules 31 walls / supermodule 52 x 64 bricks /wall 200 000 bricks Emulsion layers 9 kt-yr m2 = 1.2 x 10-3 eV2 : 2.7 events m2 = 2.4 x 10-3 eV2 : 11 events m2 = 5.4 x 10-3 eV2 : 54 events Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 2 Drift Coord. (m) Full 2D view from the Collection Wire Plane 2 4 6 Wire coord. (m)12 Installation 18 Zoom View 3.9 Proceeding! m 1.8 kt to be 1.3 m operating by 2008 T600 test @ Pv: Run 308 - Evt 7 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 What is left to measure? • More accurate determinations of already measured parameters (better than CKM?): – Existing experiments offer (modest) improvements – Next-generation long baseline and reactor experiments (T2K will improve on MINOS by ~10x). • 13 • The sign of m232 (or m132) • The CP-violating phase d Dave Wark University of Sussex/RAL Allowed by Super-K J.W.F. Valle, hep-ph/0410103 What about 13? From Maltoni et al., hep-ph/0309130 Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Higgs-Maxwell If neutrinos have mass: Feb. 9 ’05 For three neutrinos: n l Uli n i 0 0 1 0 0 c13 0 s13 U e1 U e 2 U e 3 c12 s12 0 1 U li U μ1 U μ 2 U μ3 s12 c12 0 0 c23 s23 0 1 0 0 1 0 U 0 0 s 0 0 e iδ s 0 c U U 0 1 c τ2 τ3 23 23 13 τ1 13 where cij cos ij , and sij sin ij 2 2 23 Pem sin 2 213 sin 2 sin sin 213 sin d cos 13 sin 212 sin 2 23 sin 3 sin 213 cos d cos 13 sin 212 sin 2 23 cos sin 2 2 Δm L 2 2 2 2 ν ) 2sin 2θ sin 2 P(ν ) cos 23e sin 212 sin ( 1.27 μ E 2 2 2 where m21~0.03 / m31 and m31~p/4 L / 4E And sin2213 < ~0.14 Dave Wark University of Sussex/RAL PPAP Mar. 25 ’04 ≡ T2K Dave Wark Imperial College/RAL Higgs-Maxwell Feb. 9 ’05 Far Detector. Off Axis Beam Target Horns Near Detector Decay Pipe m2=3x10-3eV2 L=295km Statistics at SK OA2° ~102 x (K2K) (OAB2deg,1yr,22.5kt) ~4500 nm tot ~3000 nm CC ne ~0.2% at nm peak nm Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 En nm + n → m + p mN Em mm2 2 mN Em pm cos m (Em , pm) n inelastic nm + n → m + p +np ccQE cc-inelastic ccQE beam energy Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 nm disappearance signal Background from NC interactions p0 e ne appearance signal m Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Data compiled by G.Zeller, hep-ex/0312061 Higgs-Maxwell Feb. 9 ’05 • To make precise measurements,need – Background cross sections – Signal (CC!) cross sections Slide stolen from Debbie Harris Dave Wark University of Sussex/RAL Conceptual design of the near neutrino detector Off-axis (~2o) Neutron shield 16m nm and ne fluxes and spectra n interaction study SK (CC-QE, non-QE and p0 ) SK direction 36m Kaon contributions Grid m profile FGD MRD 2 n beam 5m 3 20mF PMT Tracker : SciBar type Extruded Scintillator + Wave Length Shifting Fiber 1m 1m nm m Iron Veto all surface by plastic scintillator (Fibers goes through holes.) ~14m On-axis (0o) Beam direction and stability 1m 3m 1m 3m The detector design is only just started. Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Another way at 13 – a Two-Detector Reactor Experiment Look at ratio of rates/spectra Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 GeneralDetector StrategyConcept of Experiment ~200 m Sensitivity goal: sin22~0.01 ~1600 m Braidwood • 1 near detector and 2 far detectors • 6.5 m diameter spherical detectors with 3 zones (Gd-loaded scint.) • 25-50 ton fid. mass per detector, depending on required buffer regions. • Movable detectors with surface transport for cross-calibration • Near and far detectors at same depth of 450 mwe (contingent on bore holes) • Near detector at ~200 m security perimeter (L~270 m) • Far detector at ~1800 m • Full detector construction above ground Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Approved Why do more than one….? Can’t determine three parameters with one Pme. Dave Wark University of Sussex/RAL Determining the sign of m132 S. Parke @ Argonne NuMI OA meeting Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL What about 13? From Huber et al., hep-ph/0412133 Higgs-Maxwell Feb. 9 ’05 Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Make intense, energetic, clean, signselected neutrino beams from _ m e + nm + ne Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Make intense, energetic, clean, signselected neutrino beams from _ m e + nm + ne Dave Wark University of Sussex/RAL PPAP Mar. 25 ’04 CERN: -beam baseline scenario Nuclear Physics SPL Decay ISOL target & Ion source Ring SPS Decay ring Brho = 1500 Tm B=5T ECR Lss = 2500 m Cyclotrons, linac or FFAG Rapid cycling synchrotron PS 6 2 P. Zucchelli, Phys. Lett. B, 532 (2002) 166-172 Beta-beam study group Slide from M. Lindroos He 36Li e n Average Ec m s 1.937 MeV 18 10 Ne 189Fe e n Average Ec m s 1.86 MeV Dave Wark Imperial College/RAL Higgs-Maxwell Feb. 9 ’05 Neutrino Factory Physics Reach 13 CP sensitivity Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Absolute Neutrino Masses Mass Limit (eV, keV, or MeV) 10 10 4 J. Wilkerson m 3 e 10 2 t 10 10 ne (eV) nm (keV) nt (MeV) 1 0 1950 1960 1970 1980 1990 2000 Year Dave Wark University of Sussex/RAL Higgs-Maxwell So what does this all mean about neutrino mass? Feb. 9 ’05 It “probably” looks something like this Log m2 m3 m223 ~ 2.5 x 10-3 eV2 m2 m212 ~ 7 x 10-5 eV2 m1 ne nm nt Dave Wark University of Sussex/RAL Higgs-Maxwell So what does this all mean about neutrino mass? Feb. 9 ’05 But it could look like this Log m2 m3 m2 m1 m2 m1 m3 ne nm nt Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 This makes a factor of two difference in the total. ’05 But a factor of two difference in what? Log m2 m3 m2 m1 m2 m1 m3 ne nm nt Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Log m 1 eV Even more significant is the absolute scale. m3 m2 m1 This? Or this? 10-1 eV m3 m2 m1 10-2 eV ne nm nt Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Does this look natural? Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 Log m 1 eV Even more significant is the absolute scale. m3 m2 m1 This? Or this? 10-1 eV m3 m2 m1 10-2 eV ne nm nt Dave Wark University of Sussex/RAL Higgs-Maxwell Determining the absolute mass scale Feb. 9 ’05 • Supernovae – Prodigious producers of neutrinos, and measuring time shifts can in principle measure neutrino masses, mn < ~30 eV. • Kinematic limits: If you believe the oscillation results, all m2≪1 eV, therefore only ne measurements have useful sensitivity → current best is Tritium Beta Decay, mn < 2.2 eV. • If neutrinos have Marjorana masses, then zeroneutrino double-beta decay is allowed → observation of 0n decay would be direct evidence for neutrino mass, <mn> < ~1.3 eV. • Neutrinos are the second most numerous particle in the Universe → even a tiny neutrino mass could have astrophysical implications, Smn < 0.23 eV(?) Dave Wark University of Sussex/RAL Higgs-Maxwell Feb. 9 ’05 • Neutrinos have been experimentally demonstrated to have mass. • Neutrinos have been experimentally demonstrated to oscillate. • The implications for particle physics and astrophysics could be considerable. • An extensive experimental programme will be required to fully explore the oscillation parameters, and to determine the absolute masses, using accelerators, precision experiments, and astrophysics • This is an exciting, active field. • JOIN US! • Thanks to the many many people who I stole slides from… Conclusions? Dave Wark University of Sussex/RAL
