MINOS Layout. Gary Feldman SLAC Summer Institute August

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1 MINOS Layout Gary Fedman SLAC Summer Institute 14-5 August

2 MINOS Far Detector 8m octagona tracking caorimeter 486 ayers of 1 in iron pates 4.1 cm-wide scintiator strips with WLS fiber readout, read out from both ends 8 fibers summed on each PMT pixe 5,800 m (6.4 acres) of active detector panes Toroida magnetic fied <B> = 1.3 T Tota mass 5.4 kt Haf of MINOS far detector Gary Fedman SLAC Summer Institute 14-5 August

MINOS Near Detector 80 Òsquashed octagonó pates Same pate thickness, scintiator thickness and width as far detector Target/caorimeter section: 10 panes 4/5 partia area

3 MINOS Near Detector 80 Òsquashed octagonó pates Same pate thickness, scintiator thickness and width as far detector Target/caorimeter section: 10 panes 4/5 partia area instrumented 1/5 fu area instrumented Muon spectrometer section: 160 panes 4/5 uninstrumented 1/5 fu area instrumented 980 tons Gary Fedman SLAC Summer Institute 14-5 August

4 MINOS Near-Far Detector Differences Rates (8 µs spi) Eectronics Readout Near Far Comments ~ 3 MHz ~ 30 Hz Simuations not a probem Low intensity runs Deadtimeess 19 ns digitizations Singe ended w/ refector Sampe and hod Doube ended Caibrate in test beam Simiar ight eves Caibrate in test beam Mutipexing None 8-fod Simuations not a probem Gary Fedman SLAC Summer Institute 14-5 August 000 9

5 MINOS Energy Options Different beam energies correspond to different horn currents and positions Wi start with ow E beam for best sensitivity to match SK resuts Gary Fedman SLAC Summer Institute 14-5 August

6 MINOS Near-Far Energy Differences: Hadronic Hose Want near and far energy spectra to be identica. This is impossibe without focusing in the decay pipe: The soution is the hadronic hose Ñ a wire carrying 1 ka down the center of the beam pipe: Gary Fedman SLAC Summer Institute 14-5 August

7 MINOS: Advantages of the Hadronic Hose Better near-far agreement More events Gary Fedman SLAC Summer Institute 14-5 August

8 MINOS Physics Goas Verify dominant ν µ ν τ osciations τ appearance is not necessary. ν µ CC disappearance with no NC disappearance and no ν e CC appearance ν µ ν τ osciations. There is no other possibiity. Precise measurement of dominant m and sin (θ). Search for subdominant ν µ ν e and ν µ ν s osciations. Study unconventiona expanations: neutrino decay, extra dimensions, etc. Gary Fedman SLAC Summer Institute 14-5 August

9 MINOS Physics Toos ν µ CC spectrum Information from both rates and shape. The atter is independent of the near / far normaization. NC / CC ratio Independent of the near / far normaization. ν e CC appearance Use topoogica criteria: fraction of energy in first few radiation engths, shower asymmetry, etc. Gary Fedman SLAC Summer Institute 14-5 August

10 MINOS CC Spectra Low-energy beam year run Charge current spectra for sin (θ) = 1 Open = no osciation Shaded = osciation Gary Fedman SLAC Summer Institute 14-5 August

11 MINOS Sensitivity CC E spectrum 1σ contours year run Gary Fedman SLAC Summer Institute 14-5 August

12 MINOS ν τ vs. ν s Discrimination Sterie neutrino discrimination by NC/CC ratio Gary Fedman SLAC Summer Institute 14-5 August

13 MINOS ν µ ν e Sensitivity 90% c.. ν µ ν e sensitivity Preiminary graph Ñ improved cacuations being done. Eectron identification by topoogica criteria N.B. Graph is incorrect (or at east miseading) for two reasons Ñ see next side Gary Fedman SLAC Summer Institute 14-5 August

14 MINOS: ν µ ν e Subteties Need to use 3-neutrino mixing Assume that MINOS is ony sensitive to the m m mass scae. Then 13 3 P( ν νe ) = µ sin ( θ )sin ( θ )sin ( 1. 7 m L/ E). 3 θ and MINOS 3 π/ 4 oses a factor of in sensitivity to θ 13 compared to CHOOZ 13 m 3 atmospheric m m m 1 } soar m Gary Fedman SLAC Summer Institute 14-5 August

15 MINOS: ν µ ν e Subteties Matter effects are not negigibe Matter effects in the earth increase (or decrease) ν µ ν e osciations by about 5% and increase (or decrease) the osciation ength sighty. If MINOS can see ν µ ν e osciations, then it can measure the sign of m by measuring ν µ νe osciations, where the sign of the matter effect reverses. m 3 m m 1 positive m negative m m m 1 m 3 Gary Fedman SLAC Summer Institute 14-5 August

16 CERN Neutrino Beam to Gran Sasso (CNGS) Gary Fedman SLAC Summer Institute 14-5 August

17 CNGS / NuMI Comparison NuMI CNGS p Energy (GeV) pot / yr (10 19 ) ν µ CC events / kt / yr (no osciations) 300 (High E) 450 Baseine (km) Turn on Near detector(s) Yes No* *Bad choice Gary Fedman SLAC Summer Institute 14-5 August

18 CNGS: Why No Near Detectors? CERN says that the purpose of CNGS is to do appearance experiments, particuary ν τ appearance, and for these experiments near detectors are not necessary. The argument is weak: Granting the argument for ν τ appearance, observing direct ν τ appearance in 005 wi not be interesting. The rates are ow (at m = ev, events / kt-yr, before efficiency corrections), so precise measurements cannot be done. Two detectors are aways better than one, since they aow for a good contro of systematic errors and provide discovery potentia. Gary Fedman SLAC Summer Institute 14-5 August

19 CNGS: OPERA Proposa OPERA is a proposa for direct detection of ν τ using the ECC (emusion coud chamber) technique: Gary Fedman SLAC Summer Institute 14-5 August

20 OPERA Detector Emusions are in bricks. A brick with an event is identified by eectronic detectors and removed for measurement. Gary Fedman SLAC Summer Institute 14-5 August

21 OPERA Detector Active mass kt τ detection efficiency 8.7% 18 events in 5 years for m = ev Gary Fedman SLAC Summer Institute 14-5 August

22 ICANOE Proposa ICANOE is a marriage of the ICARUS and NOE proposas 4 modues, each with a 1.4 kt LAr TPC and a 0.8 kt soid caorimeter 9 kt tota Gary Fedman SLAC Summer Institute 14-5 August

23 ICANOE: Liquid Argon Detector Huge LAr TPCs have bubbe-chamber ike imaging capabiities, exceent fuy-active caorimetry, and exceent partice identification from de/dx and imaging. A rea quasieastic event from a 50 iter test chamber in the CERN ν beam Gary Fedman SLAC Summer Institute 14-5 August

24 ICANOE: Soid Detector The soid detectors consist of 5 mm magnetized iron pates sandwiched with scintiating fibers and drift tubes. They serves as tai-catchers and crosschecks for the LAr and a magnetic spectrometer. Gary Fedman SLAC Summer Institute 14-5 August

25 ICANOE: ν τ Appearance ICANOE wi detect ν τ appearance by observing ow-energy excess eectrons from the τ eνν decay. In 4 years, at m = ev, there wi be about 90 such events in the ICANOE LAr (100% detection efficiency). Anayses can aso be done with kinematic cuts for ow ν e background. Gary Fedman SLAC Summer Institute 14-5 August

26 ICANOE: ν µ ν e Osciations ICANOEÕs superb eectron identification capabiities aows for a sensitive measurement of θ 13. However, it wi be imited by systematic errors from the ack of a near detector and, probaby, the wrong beam tune. Gary Fedman SLAC Summer Institute 14-5 August

27 The Future: A Neutrino Factory? A simpe idea: Store muons in a ring with ong straight sections and observe neutrinos from the muon decays. Design can be race-track, triange, or bow tie. Straight sections need to point down to serve two experiments arcs need to point up. Gary Fedman SLAC Summer Institute 14-5 August

28 Neutrino Factory Basics Like the KARMEN experiment: if µ + stored, then + + µ e ν e ν µ. Norma CC give ony µ + and e -. ν ν osciations give e +. µ e ν osciations give µ - e ν µ. Need magnetic detection to see wrong-sign eptons and very massive detectors for rate. Eectron charge difficut emphasis on wrongsign muon detection. Gary Fedman SLAC Summer Institute 14-5 August

29 Neutrino Factory Advantages Beam background free. We-known fuxes from monochromatic parents. Narrow band beam. An advantage? Fux increases as E µ3 : E for divergence. E for the cross section. Is highest possibe E aways best? Gary Fedman SLAC Summer Institute 14-5 August

30 Neutrino Factory Parameters and Physics Goas Parameters under discussion: 0 E µ 50 GeV Lower bound from p µ > 4 GeV for detection Higher E µ is better to 10 1 decays per year Baseine about 3000 km Reason to be discussed Physics goas: Precise measurement of θ 13 Determination of the sign of m 3 Measurement of CP vioation in epton sector (δ) Gary Fedman SLAC Summer Institute 14-5 August

31 Measurement of θ 13 and Sign of m 13 If θ 13 >> sin(θ 1 ) m 1 L /E (true for SMA, ow, and vacuum soar soutions), the situation is simpe: P( ν νe ) = µ sin ( θ )sin ( θ )sin ( 1. 7 m L/ E), 3 13 enhanced or reduced by matter effects, as discussed for MINOS Matter Effect Enhancement Factor at First Osciation Maximum m 3 = ev ρ =.8 g/cc Most Sensitive Energy (GeV) Energy of First Osciation Maximum m 3 = ev ρ =.8 g/cc Baseine (km) Baseine (km) Gary Fedman SLAC Summer Institute 14-5 August

32 Measurement of θ 13 and Sign of m 13 sin (θ 13 ) reach for decays (from Barger et a., hep-ph/ v) Gary Fedman SLAC Summer Institute 14-5 August

33 Measurement of θ 13 and Sign of m 13 Sensitivity to sin θ 13 at 90% c.. from Cervera, et a., (hepph/000108) 730 km disfavored by backgrounds 7300 km disfavored by statistics Gary Fedman SLAC Summer Institute 14-5 August

34 Measurement of θ 13, the Sign of m 13, and δ However, if LMA soar osciation scenario is correct, things are much more compicated (and interesting). Sensitivity to the Òatmospheric term,ó the Òsoar term,ó and an interference term between them, a modified by matter effects. (The interference term contains the CP vioation.) To simpify as much as possibe, take sin (θ 3 ) = sin (θ 1 ) = 1, and foowing Cervera, et a., expand to second order in the sma parameters θ 13 and ( m 1 L/E), ignoring matter effects: P( ν νe ) = µ θ sin (. m L/ E) ( m1l/ E) θ ( m L/ E)sin( 17. m L/ E)cos( ± δ 17. m L/ E) Gary Fedman SLAC Summer Institute 14-5 August 000 1

35 Measurement of θ 13, the Sign of m 13, and δ For a short baseine (NuMI or CNGS), each term has the same L / E dependence and we measure [ ] P( νµ νe ) = θ ( m 1 / m ) 13 + θ13( m 1 / m 13)cos( δ) ( 17. m L/ E) 13 with a sma modification due to matter effects. If m 1 is known from soar measurements, then θ 13 can be recovered with a sma uncertainty due to the cos(δ) term. However, the cos(δ) term cannot be separated from θ 13. The CP-vioating sin(δ) term, which reverses with poarity, is ower order and has been dropped. Gary Fedman SLAC Summer Institute 14-5 August

36 Measurement of θ 13, the Sign of m 13, and δ At onger baseines, we want to use the different L / E dependence to untange the different terms, incuding the CP vioating term: P( νµ νe ) = θ13 sin ( 1. 7 m13l/ E) ( m1l/ E) θ ( m L/ E)sin( 17. m L/ E)cos( ± δ 17. m L/ E) This requires a fairy arge L / E: E ~ 6 GeV for L = 3000 km. The temptation is to increase L further. This does not work, at east for measuring CP vioation, for a somewhat subte reason. Gary Fedman SLAC Summer Institute 14-5 August

37 Measuring CP Vioation CP vioation ony occurs for three or more neutrino favors. Therefore, it has to be proportiona to every MNS matrix eement and every osciatory term. That is why it occurs ony in the interference term. For this reason, uness the soar soution is LMA, measuring CP vioation is hopeess. Using the same LMA approximation, the CP odd term in the absence of matter effects is P ( ν ν ) θ sin( δ) CP µ e = ± 13 m L m L m L sin. E sin. E sin E Gary Fedman SLAC Summer Institute 14-5 August

38 Measuring CP Vioation The probem with ong (~8000 km) baseines arises due to the matter effect for m 1. The effective m added by the earth is AE, where A = G n ev /GeV F e for earth density corresponding to L = 8000 km. In the presence of matter sin 17. sin 17. m 1L m1 AE m1 L E ± AE ± m E 1 For reasonabe energies, E ³ 4 GeV, AE is at east an order of magnitude arger than m 1. Thus, AE ± m AE. 1 Gary Fedman SLAC Summer Institute 14-5 August

39 Measuring CP Vioation Therefore, the CP odd term contains a pure matter osciation, P CP m e AL ( ν ν ) 1 µ AE sin( 54. ), which goes to zero at 8000 km, independent of a parameters. Cacuation by Cervera et a. m 3 = ev m 1 = ev θ 3 = 45 o ; θ 1 =.5 o θ 13 = 8 o ; δ = 90 o Gary Fedman SLAC Summer Institute 14-5 August

40 Measuring CP Vioation Fits by Cervera et a. for 101 decays at 50 GeV with a 40 kt detector. m 3 = ev ; m 1 = ev θ 3 = 45 o θ 1 =.5 o θ 13 = 8 o δ = 54 o Gary Fedman SLAC Summer Institute 14-5 August

41 Where to Buid a Neutrino Factory For a ~3000 km baseine, the choices are quite imited. Gary Fedman SLAC Summer Institute 14-5 August

Neutrino Oscillations

Neutrino Oscillations Heidi Schellman June 6, 2000 Lots of help from Janet Conrad Charge mass,mev tandard Model of Elementary Particles 3 Generations of Fermions Force Carriers Q u a r k s u d 2/3 2/3