1 / 29

Prospettive Sperimentali della Fisica delle Oscillazioni di Neutrini

L.Ludovici INFN Roma I. Università di Roma III 27 Gennaio 2003. Prospettive Sperimentali della Fisica delle Oscillazioni di Neutrini. Scenario attuale. Presente. LCPV - n Factory. Futuro Remoto. Q 13 – Superbeam. Futuro Prossimo. Short Abstract.

marv
Download Presentation

Prospettive Sperimentali della Fisica delle Oscillazioni di Neutrini

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. L.Ludovici INFN Roma I Università di Roma III 27 Gennaio 2003 Prospettive Sperimentali della Fisica delle Oscillazioni di Neutrini Scenario attuale Presente LCPV - nFactory Futuro Remoto Q13 – Superbeam Futuro Prossimo

  2. Short Abstract... Long-term goal: Leptonic CPV at the nFactory Uncertain perspective: technology, cost, physics. Mid-term goal: q13 discovery Q13 large? LMA ? CPV already found ? nFactory Doubtful... Only if mColl

  3. 1. EVIDENCE FOR OSCILLATION OF ATMOSPHERIC NEUTRINOS Super-Kamiokande Collaboration (Y. Fukuda et al.). Phys.Rev.Lett.81:1562 (1998) hep-ex/9807003 1597 2. OBSERVATION OF TOP QUARK PRODUCTION IN ANTI-P P COLLISIONS CDF Collaboration (F. Abe et al.). Phys.Rev.Lett.74:2626 (1995) hep-ex/9503002 919 3. OBSERVATION OF THE TOP QUARK. D0 Collaboration (S. Abachi et al.). Phys.Rev.Lett.74:2632 (1995)hep-ex/9503003 878 4. ATMOSPHERIC nm /ne RATIO IN THE MULTIGEV ENERGY RANGE Kamiokande Collaboration (Y. Fukuda et al.). Phys.Lett.B335:237 (1994) 729 5. INITIAL RESULTS FROM THE CHOOZ LONG BASELINE REACTOR NEUTRINO OSCILLATION EXPERIMENT. CHOOZ Collaboration (M. Apollonio et al.). Phys.Lett.B420:397 (1998) hep-ex/9711002 659 6. OBSERVATION OF A SMALL ATMOSPHERIC nm /ne RATIO IN KAMIOKANDE. Kamiokande-II Collaboration (K.S. Hirata et al.). Phys.Lett.B280:146 (1992) 613 7. FIRST MEASUREMENT OF THE RATE FOR THE INCLUSIVE RADIATIVE PENGUIN DECAY b ® s g. CLEO Collaboration (M.S. Alam et al.). Phys.Rev.Lett.74:2885 (1995) 611 8. LIMITS ON NEUTRINO OSCILLATIONS FROM THE CHOOZ EXPERIMENT. CHOOZ Collaboration (M. Apollonio et al.). Phys.Lett.B466:415 (1999) hep-ex/9907037 578 9. EVIDENCE FOR nm®ne OSCILLATIONS FROM THE LSND EXPERIMENT AT LAMPF. LSND Collaboration (C. Athanassopoulos et al.). Phys.Rev.Lett.77:3082 (1996) nucl-ex/9605003 553 10. EVIDENCE FOR TOP QUARK PRODUCTION IN p p COLLISIONS AT S 1/2 = 1.8-TeV. CDF Collaboration (F. Abe et al.). Phys.Rev.D50:2966 (1994) 544 11. MEASUREMENT OF A SMALL ATMOSPHERIC MUON-NEUTRINO / ELECTRON-NEUTRINO RATIO. Super-Kamiokande Collaboration (Y. Fukuda et al.).Phys.Lett.B433:9 (1998) hep-ex/9803006 534 12. MEASUREMENT OF THE RATE OF ne + d ® p + p + e- INTERACTIONS PRODUCED BY B8 SOLAR NEUTRINOS AT THE SUDBURY NEUTRINO OBSERVATORY. SNO Collaboration (Q.R. Ahmad et al.). Phys.Rev.Lett.87:071301 (2001) nucl-ex/0106015 525 13. STUDY OF THE ATMOSPHERIC NEUTRINO FLUX IN THE MULTI-GEV ENERGY RANGE. Super-Kamiokande Collaboration (Y. Fukuda et al.). Phys.Lett.B436:33 (1998) hep-ex/9805006 525 14. MEASUREMENT OF THE SOLAR ELECTRON NEUTRINO FLUX WITH THE HOMESTAKE CHLORINE DETECTOR. Bruce T. Cleveland et al. Astrophys.J.496:505 (1998) 524 15. THE ne AND nm CONTENT OF THE ATMOSPHERIC FLUX. R. Becker-Szendy et al (IMB Coll.) Phys.Rev.D46:3720 (1992) 521 500+ Cited papers 1990-2002

  4. Present evidences of neutrino mass and mixing • ne® nm,nt with Dm2 ≈ 10-4 eV2, almost (not fully) maximal mixing. • nm and/or nt NC appearance from the Sun in SNO. • “Lab Test”:reactor ne disappearance at L»200Km in Kamland (4.6s) • nm ®nt with Dm2 = (1.6¸3.9).10-3 eV2, sin22q > 0.92 at 90%CL • Super-K upward-going atmospheric nm disappearance. • Most likely nm ®ntfrom po and matter effects in Super-K (2÷3s) • “Lab Test”:nm disappearance in accelerator from K2K-I (2÷3s) • nm ® newith Dm2~ 0.1 eV2 • LSND claimed evidence of neutrino oscillation. • Unseen by KARMEN with marginal sensitivity • Controversy to be solved by Mini-BooNE (results in 2004-5)

  5. The Mixing Matrix ( ) ( ) C12 S120 -S12 C12 0 0 0 1 C13 0 S13eid 0 1 0 -S13e-id 0 C13 1 0 0 0 C23 S23 0 -S23 C23 U = UA.U13.US = ?? solar atmospheric 3 neutrinos®2 mass differences, 3 angles and 1 CP phase Dm212Dm223 q12q23q13 d n1 n2 n3 ne nm nt back to flavour eigenstates pure flavour eigenstate = Uai each mass eigenstate takes a different phase P(na® nb) = dab - 4 SRe[Wab] sin2Djk ±2 SIm[Wab] sin 2Djk jk jk ( ) k>j k>j CP odd * * jk Djk = Dm2jk(eV2)L(Km)/En (GeV) , Wab = Uaj Ubj Uak Ubk

  6. Knowledge of mixing parameters • Solar ndo mix.NC appearance in SNO “Lab” confirmation: claim of disappearance in KamLand • Atmospheric n disappear. Up/Down asymmetry inSuper-K “Lab” confirmation: indication of disappearance in K2K • ne® nm Negative result inCHOOZ Dm223 = Dm2atm=1.6¸4.10-3 eV2 Dm212 = Dm2sun=(0.6¸0.9).10-4 or (1.3¸2.0).10-4 eV2 q23 ~ 45o q12~45o • q13 < 13o • d No idea. <

  7. ( ) ( ) Effective Mixing Angles P(na® nb) = dab - 4 SRe[Wab] sin2Djk ±2 SIm[Wab] sin 2Djk jk jk ( ) k>j k>j CP odd * * jk Djk = Dm2jk(eV2)L(Km)/En (GeV) , Wab = Uaj Ubj Uak Ubk For experiments at terrestrial baselines, with D12<<1: P(ne® nm) @ sin22q13 sin2q23 sin2 D23 = sin22qmesin2 D23 P(nm® nt) @ cos4q13 sin22q23 sin2 D23 = sin22qmtsin2 D23 P(ne® nt) @ sin22q13 cos2q23 sin2 D23 = P(nm® nm) @ = 1 – (sin22qmt+sin22qme)sin2 D23 P(ne® ne) @ 1 - sin22q13 sin2 D23 Only 3 parameters: q23Dm23 q13 Reduce to two flavour mixings with effective mixing angles: sin22qmt = cos4q13 sin22q23@ sin22q23 sin22qme = sin22q13 sin2q23 @ 0.5 sin22q13

  8. ( ) ( ) LCP Asymmetry Being q13 small, if Dm212 is only 10¸100 times smaller than Dm223 (LMA): P(ne® nm) @ sin2q23 sin22q13 sin2 D13 + + cos2q23 sin22q12 sin2 D12 + + JD12 sinD13 cos( ±d- D13) J = cos q13 sin2q12sin2q23sin2q13 large large large ?? “atmospheric” “solar” ( ) “interference” µJ determinant ne«nm gives the best opportunity for LCPV due to the suppression of the leading CP conserving contributions LCP asymmetry vanishes for small q13. Discovery of non-zero q13 is a pre-requisite of any sensible experimental strategy to attack the difficult problem of LCPV.

  9. The Neutrino Factory Idea F~g-2~Em2/mm2 50% nm(nm) m+(m-) 10-1000kt Mass Detector 50% ne(ne) mSR SBL (100¸1000 Km) LBL (1000¸5000 Km) VLBL (1¸2 REARTH ) n-Factory Kosharev 1974 Wojcicki 1974 Collins 1975 Geer 1998 m-collider Budker 1969 Skrinski 1971 Neuffer 1979 Conventional “pion” beams are dominantly nm (nm) with a ~few percent contaminations of nm (nm) ne ne. Difficult to access all transitions and oscillation parameters are measured with uncertainty O(10%) while NuFact beams could allow O(1%) precision.

  10. Em2Nm dN @ Fn (y) pmm2L2 dydS q=0 Neutrino Factory Fluxes • Well known flux (m decay kinematic, polarisation) • Clean beam composition: 1:1 nm+ne (or nm+ne) • Flux scales with NmEm2 /Lm2 • Average neutrino energy scales with Em • Interaction rate scales with MDETNmEm3/Lm2 P. Lipari, hep-ph/0102046 Em= 5,10,20,40 GeV m®ne L= 1000 Km Fnm(y) = 2y2 (3-2y) Q(y) Q(1-y) Fne(y) = 12y2 (1-y) Q(y) Q(1-y) s ( n )@0.67 . 10-38 . En (GeV) cm2 s ( n )@0.34 . 10-38 . En (GeV) cm2

  11. LCPV at the nFactory P(ne®nm) - P(ne®nm) P(ne®nm) + P(ne®nm) CP 2 possible ways: Aem = Aem = Earth is CP-odd. In LBL and VLBL experiments (L>1000 Km) the effects of propagation in matter are in general large and P(na®nb) ¹ P(na®nb) even if CP is conserved. P(ne®nm) - P(nm®ne) P(ne®nm) + P(nm®ne) T ACP at NuFact comparing wrong sign m- in a n beam from m+ with the charge conjugate process and beam. Need subtraction of matter induced CP effects (two detectors at different baselines). Need precise knowledge of the relative neutrino (anti-) cross-sections. AT free from matter induced effects but it requires the lepton ID and charge determination not only for muons but also for electrons, very difficult in practice in a large O(50Kt) detector.

  12. HARP MiniBooNE KamLand Roadmap K2K-II NOW nm disappearance Dm212,q12 at 2% LSND? MICE 2005 CNGS • appearance NC/CC NuMI JHFn Q13 down to 1o nF R&D 2010 ? Off-Axis ? JHF-HK Q13 LCP violation Q13 down to 0.1o 2015 ? nFactory LCP violation 2020

  13. JHFn Physics Programme High intensity neutrino beam from JHF (0.75 MW) to Super-K (50kt) Phase I 1. Discovery of q13 down to sin22q13 > 0.006 2. Precision measurement of sin22q23 and Dm223 3. Search for sterile components through NC interactions JHF upgrade to 4 MW power. Construction of Hyper-K (1Mt) Phase II 1. Discovery of q13 down to sin22q13 > 0.001 2. Leptonic CP violation. d down to 10-20 degrees if sin22q13 > 0.01

  14. Current(mA) Energy(GeV) JHF facility • KEK-JAERI joint project • JAERI@Tokai-mura, 295 Km from • Super-K (60Km NE of KEK) • Construction 2001-2007 • Cost: 1335(1890) Oku Yen (1 Oku=108)

  15. Off-Axis neutrino Beams BNL proposal E889 http://minos.phy.bnl.gov/nwg/papers/E889 Decay Pipe Horns Target n Detector q 1 mp2 – mm2 mp2 En= Fn= (Ep - ppcosq)2 4p L2 2 (Ep - ppcosq) Ep >>mp, andQ <<1 1 1 Ep mp2 – mm2 2 Ep (1 + gp2q2)2 mp2 (1 + gp2q2) mp p L2 • Much higher flux than old-style NBB. • Strong cut-off of HE tail. • Reduced ne contamination. •  Tune energy to maximise sensitivity • D = 1.27 . Dm2(eV2) . L(Km) / E(GeV) •  Beam energy almost fixed by geometry

  16. JHFn Beam • 3.3.1014 ppp at 0.285 Hz (0.75 MW, 2.64 MJ/pulse) • 1021 pot/yr in 130 days/yr • SC proton transport line • Carbon target • Secondary pions focused by horns • Decay pipe 130m length from target • Near detector at 280m from target • Intermediate detector at 1.5Km • Super-K at 295 Km. (22.5 kt fiducial) • Beam steering angle 2.5o±0.5o. • Tune energy between 0.4 and 1 GeV • Best tuning to Dm2=(1.6¸4).10-3 eV2 q=1o q=2o q=3o

  17. JHFn Near Detectors Flux.L2 @ Super-K Flux.L2 @ 1.5 Km Flux.L2 @ 0.28 Km Near detector at 280 m • Covers from 0o to 3o. • Monitor the beam stability and flux. • High rate: 60 events/kt/spill. • Study nm and ne interactions: CCQE, CC, NC. • Non point-like n source, different target, different detector technology: flux extrapolation to Super-K problem. Intermediate detector at 1.5 Km 60% difference • Off-Axis as Super-K • Water-Cherenkov (100t fiducial mass) to cancel most of the flux extrapolation syst. • Spectrum differences < 10% ® 2% systematic due to ne background subtraction. Better than 10%

  18. Detector at 1.5Km Conceptual design.

  19. Far detector

  20. Ereco (MeV) s=80MeV Etrue (MeV) Ereco - Etrue (MeV) Neutrino Energy Measure Almost exact (Fermi motion) for QE interactions: nl n ®l p CCQE mnEl – ml2/2 Enrec = mn–El + Plcosql non-QE CC interactions of higher energy neutrinos ® background for nm disappearance non-QE background Coherent po production from NC interactions of higher energy neutrinos is a background for ne appearance

  21. Q13 (ne appearance) Dm2=3.10-3 sin2q13=0.1 e/po separation 1. Forward cut 2. high inv.mass cut 3. 1-2 rings likelihood cut 4. Ring balance cut

  22. Q13 sensitivity

  23. Dm23, q23 (nm disappearance) Survival probability Measured/Non-Oscillated 22.5kt x 5 year • Measured spectrum in Super-K: • Muon-like FC events in SK • Neutrino energy reconstruction • Subtraction of non-QE backg. sin22q • Non-oscillated spectrum: • Muon-like events in Near Detec. • Neutrino energy reconstruction • Subtraction of non-QE backg. • Near-Far extrapolation Dm2 Fit with: P(nm® nm) = 1 -sin22q23 cos4q13 sin2D23 Oscillation pattern clearly visible High precision determination: d sin22q23 = 0.01 dDm223 = 4.10-5 eV2

  24. Search for sterile neutrinos NC interactions sensitive to all active neutrinos. Together with nm®nmand nm®ne, NC provide a measurement of nm®ntand nm®ns. Expected single po events 22.5kt x 5 year NC selection of single po, lepton-less events: nN®nN po 90%CL bands po production cross-section accurately measured (better than 5%) in the near detectors. No way to reconstruct the neutrino energy. Narrow Band neutrino beam essential.

  25. JHF-II (>2012) 0.75 ® 4MW beam power 50 kt ® 1 Mt water Cherenkov (Hyper-Kamiokande) 3x105 events/year Leptonic CPV

  26. CPV Sensitivity of JHF-II 0.14 Q13 excluded by CHOOZ 0.12 Sin22Q13 Stat+BG 10%syst 0.10 If JHF-I discovers non-zero q13, than JHF-II will be sensitive to LCPV down to d=10-20 degrees. Stat+BG 5%syst 0.08 Stat+BG 2%syst Stat+BG no syst 0.06 0.04 Stat. Only. No BG 0.02 Q13 not reachable by JHF-I 0 0.2 0.1 1 0.7 0.4 0.9 0.6 0.3 0.8 0 0.5 sin d sin22q12 P(ne®nm) - P(ne®nm) P(ne®nm) + P(ne®nm) Dm212L . . sin d CP = Aem = sin q13 4 En (without matter effects)

  27. Status of JHFn • La costruzione di JHF è iniziata nel 2001 e il primo fascio è atteso nel 2007. • La fase-I (0.75MW) è approvata e finanziata (oltre 1M€). • Il programma di neutrini è una delle principali motivazioni per la costruzione della facility. • L’approvazione e il finanziamento della neutrino beam-line è atteso per questa estate in Giappone (MEXT). • Una prima LoI è apparsa nel 2001. • Nel 2002 si sono tenuti due workshop internazionali, con partecipanti da Giappone, Canada, Francia, Italia, Corea, Russia, Spagna, UK e USA. • Sono stati formati dei working groups internazionali. • Una LoI aggiornata è stata inviata nel gennaio 2003, firmata da istituti in Giappone, Canada, Francia, Italia (Bari,Napoli,Padova,Roma I), Corea, Polonia, Russia, Spagna, Svizzera, UK and USA. JHFn è il progetto più interessante per scala dei tempi, strategia sperimentale, flessibilità e ricchezza del programma scientifico. La partecipazione italiana deve rafforzarsi per contribuire in modo rilevante e visibile.

  28. Conclusioni Finora • La fisica delle oscillazioni di neutrini vive anni di importanti risultati. • I neutrini solari oscillano. Evidenza di neutrini attivi non-ne dal sole. Conferma da una sorgente artificiale. • Forte indicazione di sparizione dei nm atmosferici. Conferma (non conclusiva) da una sorgente artificiale. Next (qualche anno) • K2K-II: Conferma sparizione nm . Pattern di oscillazione. • NuMi: NC/CC, sterili/tau • CNGS: apparizione diretta di tau • MiniBooNE: LSND? Next2 (entro il decennio) • Ricerca di q13. Segno di Dm223 (gerarchia) ?. • Misura di precisione dei parametri (GUT test, mass models,...) Next3 (....) • Leptonic CP violation. • Test del triangolo di unitarietà

  29. HARP MiniBooNE KamLand Roadmap K2K-II NOW nm disappearance Dm212,q12 at 2% LSND? MICE 2005 CNGS • appearance NC/CC NuMI JHFn Q13 down to 1o nF R&D 2010 ? Off-Axis ? JHF-HK Q13 LCP violation Q13 down to 0.1o 2015 ? nFactory LCP violation 2020

More Related