1 / 50

A neutrino beam to IceCube/PINGU? (PINGU = “Precision IceCube Next-Generation Upgrade“)

A neutrino beam to IceCube/PINGU? (PINGU = “Precision IceCube Next-Generation Upgrade“). NPAC (Nuclear/Particle/Astro/Cosmo) Forum UW-Madison, USA May 15, 2012 Walter Winter Universität Würzburg. TexPoint fonts used in EMF: A A A A A A A A. Contents. Introduction

malaya
Download Presentation

A neutrino beam to IceCube/PINGU? (PINGU = “Precision IceCube Next-Generation Upgrade“)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. A neutrino beam to IceCube/PINGU?(PINGU = “Precision IceCube Next-Generation Upgrade“) NPAC (Nuclear/Particle/Astro/Cosmo) Forum UW-Madison, USA May 15, 2012Walter Winter Universität Würzburg TexPoint fonts used in EMF: AAAAAAAA

  2. Contents • Introduction • Oscillation physics using a core-crossing baseline • Neutrino beam to PINGU: Beams and detector parameterization • Detector requirements for large q13 • Comments on LBNE reconfiguration • Summary

  3. ( ) ( ) ( ) = x x Three flavor mixing • Use same parameterization as for CKM matrix Pontecorvo-Maki-Nakagawa-Sakata matrix Potential CP violation ~ q13 (sij = sin qij cij = cos qij)

  4. q13 discovery 2012 • First evidence from T2K, Double Chooz • Discovery (~ 5s) independently (?)by Daya Bay, RENO Daya Bay 3s 1s error bars (from arXiv:1204.1249)

  5. Mass spectrum/hierarchy • Specific models typically come together with specific MH prediction (e.g. textures are very different) • Good model discriminator (Albright, Chen, hep-ph/0608137) 8 8 Normal Inverted

  6. Three flavors: Summary • Three flavors: 6 params(3 angles, one phase; 2 x Dm2) • Describes solar and atmospheric neutrino anomalies, as well as reactor antineutrino disapp.! Solaroscillations:Amplitude:q12Frequency: Dm212 Atmosphericoscillations:Amplitude:q23Frequency: Dm312 Coupling: q13 (Super-K, 1998;Chooz, 1999; SNO 2001+2002; KamLAND 2002;Daya Bay, RENO 2012) Suppressed effect: dCP

  7. Consequences Huber, Lindner, Schwetz, Winter, 2009 • Parameter space for dCP starts to become constrained; MH/CPV difficult (need to exclude dCP=0 and p) • Need new facility!

  8. 90% CL, existing equipment 3s, Project X and T2K with proton driver, optimized neutrino-antineutrino run plan Mass hierarchy discovery? Huber, Lindner, Schwetz, Winter, JHEP 11 (2009) 44

  9. Mass hierarchy measurement? • Mass hierarchy [sgn(Dm2)] discovery possible with atmospheric neutrinos? (liquid argon, HyperK, MEMPHYS, INO, PINGU?, LENA?, …) Barger et al, arXiv:1203.6012;IH more challenging Perhaps differentfacilities for MH and CPVproposed/discussed? • However: also long-baseline proposals! (LBNO: superbeam ~ 2200 km – LAGUNA design study; CERN-SuperK ~ 8870 km – Agarwalla, Hernandez, arXiv:1204.4217; South Pole: Dick et al, 2000)

  10. Oscillation physics using a core-crossing baseline

  11. What is PINGU? What is PINGU? 2012

  12. PINGU fiducial volume? • A few Mt fiducial mass for superbeam produced with FNAL main injector protons (120 GeV) LBNE-beam (Jason Koskinen)

  13. Beams to PINGU? • Labs and potential detector locations (stars) in “deep underground“ laboratories: (Agarwalla, Huber, Tang, Winter, 2010) FNAL-PINGU: 11620 kmCERN-PINGU: 11810 kmRAL-PINGU: 12020 kmJHF-PINGU: 11370 km NEW? All these baselines cross the Earth‘s outer core!

  14. Matter profile of the Earth… as seen by a neutrino Core (PREM: Preliminary Reference Earth Model) Innercore

  15. Matter effect (MSW) (Wolfenstein, 1978; Mikheyev, Smirnov, 1985) • Ordinary matter: electrons, but no m, t • Coherent forward scattering in matter: Net effect on electron flavor • Hamiltonian in matter (matrix form, flavor space): Y: electron fraction ~ 0.5 (electrons per nucleon)

  16. Parameter mapping • Oscillation probabilities invacuum:matter: Matter resonance: In this case: - Effective mixing maximal- Effective osc. frequency minimal For nm appearance, Dm312:- r ~ 4.7 g/cm3 (Earth’s mantle): Eres ~ 6.4 GeV- r ~ 10.8 g/cm3 (Earth’s outer core): Eres ~ 2.8 GeV  MH Resonance energy:

  17. Mantle-core-mantle profile (Parametric enhancement: Akhmedov, 1998; Akhmedov, Lipari, Smirnov, 1998; Petcov, 1998) • Probability for FNAL-PINGU (numerical) ! Inter-ference Parametric enhancementthrough mantle-core-mantleprofile of the Earth.Unique physics potential! Core resonanceenergy Mantleresonanceenergy Beam energyand detector threshold have to pass ~ 2 GeV!Naive L/E scalingdoes not apply! Thresholdeffects expected at: 2 GeV 4-5 GeV

  18. Neutrino beam to PINGU? Beams and detector parameterization

  19. Possible neutrino sources There are three possibilities to artificially produce neutrinos • Beta decay: • Example: Nuclear reactors, Beta beams • Pion decay: • From accelerators: • Muon decay: • Muons produced by pion decays! Neutrino Factory Superbeam Muons,neutrinos Pions Neutrinos Protons Target Selection,focusing Decaytunnel Absorber

  20. Considered setups • Single baseline reference setups: • Idea: similar beam, but detector replaced by PINGU/MICA [need to cover ~ 2 – 5 GeV]: L [km] (for details: Tang, Winter, JHEP 1202 (2012) 028, arXiv:1110.5908; Sec. 3)

  21. Oscillation channels Want to study ne-nm oscillations • Beta beams: • In principle best choice for PINGU (need muon flavor ID only) • Superbeams: • Need (clean) electron flavor sample. Difficult? • Neutrino factory: • Need charge identification of m+ and m- (normally)

  22. PINGU fiducial volume? • In principle: Mton-size detector in relevant ranges: • Unclear how that evolves with cuts for flavor-ID etc. (background reduction); MICA even larger? • Use effective detector parameterization to study requirements: Eth, Veff, Eres Eres (DE) = x E Veff Eth (Tang, Winter, JHEP 1202 (2012) 028; Veff somewhat smaller than J. Koskinen ‘s current results)

  23. Detector paramet.: mis-ID misID: fraction of events of a specific channelmis-identified as signal misIDtracks << misID <~ 1 ? (Tang, Winter, JHEP 1202 (2012) 028)

  24. Detector requirements for large q13

  25. Superbeam (LBNE-like) (misIDtracks = 0.01) • Mass hierarchy measurement very robust(even with largemisID and totalrates only possible) Fraction of dCP (Tang, Winter, JHEP 1202 (2012) 028)

  26. Low-intensity alternative? • Use existing equipment, new beam line • Here: use most conservative assumption NuMI beam, 1021 pot (total), neutrinos only[compare to LBNE: 22+22 1020 pot without Project X ~ factor four higher exposure than the one considered here](FERMILAB-PROPOSAL-0875, NUMI-L-714) • Low intensity allows for shorter decay pipe (rough estimate: ~ 100 m for 700kW beam) • Advantage: Peaks in exactly the right energy range for the parametric enhancement due to the Earth‘s core (Tang, Winter, JHEP 1202 (2012) 028)

  27. Detector parameterization • Challenges: • Electron flavor ID • Systematics (efficiency, flux normalization  near detector?) • Energy resolution • Make very (?) conservative assumptions here: • Fraction of mis-identified muon tracks (muon tracks may be too short to be distinguished from signal) ~ 20% • Irreducible backgrounds (zeroth order assumption!): • Intrinsic beam background • Neutral current cascades • nm nt cascades (hadronic and electromagnetic cascades indistinguishable) • Systematics uncorrelated between signal and background • No energy resolution (total rates only) (for details on parameterization: Tang, Winter, JHEP 1202 (2012) 028)

  28. Event rates (Daya Bay best-fit) PRELIMINARY >18s(stat. only)

  29. NuMI-like beam to PINGU? • Very robust mass hierarchy measurement (as long as either some energy resolution or control of systematics); track mis-identification maybe too conservative GLoBES 2012 (Daya Bay best-fit; current parameter uncertainties, marginalized over) PRELIMINARY All irreducible backgrounds included

  30. Probabilities: dCP-dependence • There is a rich dCP-phenomenology: PRELIMINARY NH (probably works for NH only!?)

  31. Upgrade path towards dCP? • Measurement of dCP in principle possible, but challenging • Requires: • Electromagnetic shower ID (here: 1% mis-ID) • Energy resolution (here: 20% x E) • Maybe: volume upgrade(here: ~ factor two) • Project X • Performance and optimization of PINGU, and possible upgrades (MICA, …) require further study = LBNE + Project X! same beamto PINGU (Tang, Winter, JHEP 1202 (2012) 028)

  32. Beta beam • Similar results for mass hierarchy measurement (easy) • CPV less promising: long L, asymmetric beam energies (at least in CERN-SPS limited case g~656 for 8B and g=390 for 8Li) although moderate detector requirements (misID ~ 0.001, Eth=2 GeV, Eres=50% E, Veff=5 Mt) (Tang, Winter, JHEP 1202 (2012) 028)

  33. Neutrino factory • No magnetic field, no charge identification • Need to disentangle Pem and Pmm by energy resolution: (from: Tang, Winter, JHEP 1202 (2012) 028; for non-magnetized detectors, see Huber, Schwetz, Phys. Lett. B669 (2008) 294) )

  34. nt contamination • Challenge:Reconstructed at lower energies!(Indumathi, Sinha, PRD 80 (2009) 113012; Donini, Gomez Cadenas, Meloni, JHEP 1102 (2011) 095) • Choose low enough Em to avoid nt • Need event migration matrices (from detector simulation) for reliable predictions! (neutral currents etc) (sin22q13=0.1) (Tang, Winter, JHEP 1202 (2012) 028)

  35. Matter density measurementExample: LBNE-like Superbeam • Precision ~ 0.5% (1s) • Highly competitive to seismic waves (seismic shear waves cannot propagate in the liquid core!) (Tang, Winter, JHEP 1202 (2012) 028)

  36. LBNE reconfiguration (some personal comments) Thanks discussions with:A. de Gouvea, F. Halzen, J. Hylen, B. Kayser, J. Kopp, S. Parke, PINGU collaboration, …

  37. D ~ 600M$

  38. Landscape(before reconfiguration) • LBNE one out of many options to measure CPV • Can this reach be matched in a phased approach? • How can one define a truly unique experiment for <= 600M US$? • How would one react if T2HK happens? (P. Huber)

  39. Reconfiguration options?… or how to spend 600 M$ • New detector, existing beam line • MINOS site (L=735 km) • NOvA site (L=810 km) • New site? • New (smaller) detector, new beam line (~300 M$) • Smaller detector in Homestake (L=1300 km) • Surface detector at Homestake (L=1300 km) • New beam line (<= 550 M$?), (then) existing detector • PINGU (L=11620 km) • … Idea ~ 2 weeks old

  40. Best physics concept? NuMIbeam line Homestake, on-axis Newbeam line (Barger, Huber, Marfatia, Winter, PRD 76 (2007) 053005)

  41. Conclusion:LBNE – smaller version? • How many s does one need? • Combination of experiments tolerable as physics result? This is whatT2HKcannot do MH, 5s This is whatT2HKcan also do

  42. Conclusions: FNAL-PINGU? • FNAL-PINGU • Megaton-size ice detector as upgrade of DeepCore with lower threshold; very cost-efficient compared to liquid argon, water • Unique mass hierarchy measurement through parameteric enhancement; proton beams from main injector may just have right energy • In principle, MH even with counting experiment measurable (compared to MH determination using atmospheric neutrinos) • Challenges on beam side (questions from PINGU meeting): • Tilt of beam line – feasibility, cost? • Near detector necessary? Maybe not, if 10% systematics achievable … • Beam bunching (to reduce atmospheric backgrounds)? NB: very low exposure required for MH; shorter decay pipe, one horn only, …? • Perspectives • CP violation challenging (requires energy resolution, flavor identification), but not in principle excluded; needs further study on detector side • Measurement of Earth‘s core density, in principle, possible(Tang, Winter, JHEP 1202 (2012) 028) • Upgrades of PINGU discussed (MICA) • Truly unique and spectacular long-baseline experiment with no other alternative proposed doing similar physics!? The LBNE alternative if T2HK is going to be funded?

  43. BACKUP

  44. NOvA+INO (atm.)? MH, 3s (Blennow, Schwetz, arXiv:1203.3388)

  45. NF: Precision measurements? … only if good enough energy resolution ~ 10% E and misID (cascades versus tracks) <~ 1% can be achieved!Requires further study … (Tang, Winter, JHEP 1202 (2012) 028)

  46. Beams: Appearance channels (Cervera et al. 2000; Freund, Huber, Lindner, 2000; Akhmedov et al, 2004) • Antineutrinos: • Magic baseline:L~ 7500 km: Clean measurement of q13 (and mass hierarchy) for any energy, value of oscillation parameters!(Huber, Winter, 2003; Smirnov 2006)In combination with shorter baseline, a wide range of very long baseline will do! (Gandhi, Winter, 2006; Kopp, Ota, Winter, 2008)

  47. Quantification of performanceExample: CP violation discovery Best performanceclose to max. CPV (dCP = p/2 or 3p/2) Sensitive region as a function of trueq13 anddCP dCP values now stacked for each q13 No CPV discovery ifdCP too close to 0 or p No CPV discovery forall values of dCP 3s ~ Precision inquark sector! Read: If sin22q13=10-3, we expect a discovery for 80% of all values of dCP

  48. Effective volume • Difference Eth = 2 GeV, Veff=5 Mt to actual (energy-dependent) fiducial volume: (Tang, Winter, JHEP 1202 (2012) 028)

  49. VL baselines (1) Note: Pure baseline effect!A 1: Matter resonance Prop. To L2; compensated by flux prop. to 1/L2 (Factor 1)(Factor 2) (Factor 1)2 (Factor 2)2

  50. VL baselines (2) • Factor 1:Depends on energy; can be matter enhanced for long L; however: the longer L, the stronger change off the resonance • Factor 2:Always suppressed for longer L; zero at “magic baseline” (indep. of E, osc. Params) (Dm312 = 0.0025, r=4.3 g/cm3, normal hierarchy) • Factor 2 always suppresses CP and solar terms for very long baselines; note that these terms include 1/L2-dep.!

More Related