Future Neutrino Projects Beyond 13. Ed Kearns Boston University

Transcription

1 Future Neutrino Projects Beyond 13 Ed Kearns Boston University October 28, 2008

2 If θ 13 > 0.01 from T2K/NOνA/CNGS and Double Chooz/Daya Bay/RENO... Verify the 3 3 Neutrino Framework: Measure phase δ demonstrate CPV Determine Mass Hierarchy (if not already done) Refine measurements, especially θ A Neutrino Factory in combina\on with a magne\c detector is the op\mum experiment to verify the 3x3 framework, that we know of. For this talk, I will consider that technically out of reach at this \me. 2

3 The physics objec\ve of CPV and hierarchy determina\on can be accomplished with a conven\onal, high intensity, super beam plus a Megaton Scale detector. J PARC 0.75 MW (T2K) 1.66 MW FNAL 0.4 MW (NuMI) MW CERN 0.5 MW (CNGS) 4 MW (SPL) Water Cherenkov 22.5 kton (SK) kton Fine Grained 15 kton (NOνA) kton (LAr) The experimental issues remains essen\ally the same as with the prior genera\on: look for CCQE ν e, NC π 0 serious BG, beam ν e is irreducible. However, we now run with ν and an\ ν and need large sta\s\cs. 3

4 atmos. CP viola\ng CP conserving solar for an\ neutrinos, sign of x and sin δ cp is changed 4

5 Spread increases with baseline L = 1000 km Neutrinos and An\ neutrinos reverse places with hierarchy CPV effect 3x larger at 2 nd maximum than 1 st 5

6 Observables: P(ν µ ν e ) P(ν µ ν e ) Use spectral informa\on or mul\ple experiments (baselines or reactor) to resolve degenerate solu\ons. 6

7 hlp://j parc.jp/np08/ T. Hasegawa NP08 7

8 ν meters 2 detector caverns 270 kton kton fiducial mass ( 1 Mt total) 200,000 PMTs (for 40% coverage) 2.5 OA (other side of beam) Reduced overburden from SK: 500 m (vs 1 km) 8

9 K. Kaneyuki NP08 Sensi\vity to CPV: 50% δ coverage (3σ) for sin 2 2θ 13 = 0.03 Even for only 5 years running; 10 years slightly beler Preliminary systema\cs of 5% on: signal, NC BG, beam BG, ν/an\ ν Hierarchy should be known to remove degenerate solu\on 9

10 Measure both first and second maximum S\ll 270 kton kton fiducial mass Eliminates many degeneracies Controls systema\c uncertainty. M. Ishitsuka et al., Phys.Rev.D72:033003,

11 Osc. Prob. Neutrino Flux 2nd Maximum 1st Maximum L ~ 1000 km 11

12 F. Dufour NOW 08 12

13 F. Dufour NOW 08 13

14 F. Dufour NOW 08 Sensi\vity to CPV: > 70% δ coverage (3σ) for sin 2 2θ 13 > years running 15 systema\c uncertainty terms, most = 5%; 20% in normaliza\on > 1.2 GeV CPV reach insensi\ve to angle, but 1 OA quasi WBB benefits hierarchy study 14

15 A new possibility under inves\ga\on... T. Maruyama NP08 Kamioka 295 km 2.5 OA 0.6 GeV (1 st ) 0.2 GeV (2 nd ) Okinoshima 650 km 10/28/ OA 1.3 GeV (1 st ) 0.4 GeV (2 nd ) 15

16 Marciano, hep ph/ Diwan et al., hep ex/ Barger et al., arxiv: In post Tevatron era, Fermilab s long range plan is converging on the high intensity fron\er. The flagship project would be a new 1 2 MW beam towards DUSEL. Unique feature is longest baseline being considered (1300 km) GeV protons fed by Project X kton Water Cherenkov and/or ~100 kton LAr TPC. 16

17 M. Bishai, UDIG GeV protons, 2.4 MW 0.5 OA Used for next plots 60 GeV protons, 1.2 MW 0 OA comparable sensi\vi\es 17

18 M. Dierckxsens, UDIG 08 18

19 M. Dierckxsens, UDIG 08 It is assumed that NC BG is completely removed for LAr. Remains to be demonstrated! 19

20 Water Cherenkov Liquid Argon M. Dierckxsens, UDIG 08 Sensi\vity to CPV: > 50% δ coverage (3σ) for sin 2 2θ 13 > years running BG uncertainty = 5%; assume perfect BG rejec\on for LAr (80% signal efficiency) 20

21 21 M. Dierckxsens, UDIG 08

22 Eν (reco.) proton π 0 γ 1 γ GeV 691 MeV/c 1442 MeV/c 1204 MeV/c 245 MeV/c Sensi\vity studies suggest a factor of 3 6 in equivalent mass for LAr over WC. 22

23 LANNDD astro ph/ FLARE hep ex/ v1 Modules with wires Large volume with wires Large volume without wires purifica\on dri{ length low noise electronics automa\c reconstruc\on detailed design: materials, feed throughs, etc. safety underground GLACIER hep ph/ World wide R&D effort Need long term demonstra\on of an opera\ng detector that generates physics results. 23

24 Next Generation Water Cherenkov Detector Configurations 24

25 Well tested technology with mature knowledge base Inexpensive source of mass Good calorimetry Performs beler at tracking at Sub GeV energies What PMT coverage? (depends on physics topic) SK2 experience shows 20% good enough for most. Lower? PMT costs drive the experiment cost. Current R&D hopes to lower cost, but s\ll basically PMT technology. Must design in safety against chain reac\on Current thinking is to use smaller tubes, lower density. Drives maximum water depth. Many other details, eg. moun\ng, water purifica\on etc. Previously solved, but may require new ideas, especially regarding cost. Gadolinium (n capture) may add value for some physics topics. 25

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27 J. Campagne et al, JHEP 04 (2007) 003 Short baseline: 130 km 440 kton total fiducial mass of WC 3.5 GeV Super Proton LINAC (4 MW) beta beam 5.8/2.2e18 He/Ne dcy/y Performance similar to J PARC HK Advocate using atmospheric n to resolve degeneracies 27

28 It is important to consider the added value from other scien\fic topics besides accelerator based neutrino oscilla\on. 1A Nucleon Decay 1B Supernova Neutrino Burst 2 Diffuse Relic Supernova Neutrinos 3 Atmospheric Neutrinos 4 Solar Neutrinos 28

29 Guaranteed signal if you run for long enough. Enormous sta\s\cs (200,000 events) in a megaton scale WC detector. Time profile and spectra of great astrophysical interest. Exo\c possibili\es such as Si burning and black hole forma\on. Standard picture: Ini\al burst of ν e and cooling tail of equal flavors. May reveal fundamental neutrino physics as well: mass hierarchy via maler effects 29

30 (1) Neutroniza\on peak (2) Shock wave development M. Nakahata et al. numbers for 1 Mton R. Tomas, et al. JCAP 0409, (3) Earth maler effects if >1 detector in world and some geometric luck LAr can par\cipate too: ν e CC ( 40 Ar, 40 K * ) ν e CC events/380 neutroniza\on for 100 kt, 10kpc 30

31 Γ αm 4 X m 5 p e + ν p π 0 K + Highly prized physics mo\va\on: Grand Unifica\on of strong, weak, and electromagne\c forces. Grand Unifica\on of quarks and leptons. New force carrying par\cle! Connec\ons to neutrino mass, infla\on, BAU... Test of basic symmetries: baryon number and lepton number. Supersymmetric versions of GUTs are of great interest: LHC connec\on? ~10 15 GeV energy scale inaccessible to accelerators. Long life\me limits (from SK) are already difficult constraints which new models must work hard to evade. Even failure to detect proton decay is having a significant impact on theory. 31

32 Sensi\vity versus \me for a plausible schedule for three 100 kton WC detectors followed by a 100 kton LAr TPC Lifetime Sensitivity (90% CL) SK1 SK2 SK3/ kton LAr 300 kton 200 kton 100 kton Efficiency ~45% due to nuclear absorp\on of π 0 (WC and LAr) Background from atmospheric neutrinos ~ 2 evts/mt yr Bright signature in WC, low PMT coverage should perform well. 32 Year

33 Sensi\vity versus \me for a plausible schedule for three 100 kton WC detectors followed by a 100 kton LAr TPC kton LAr Lifetime Sensitivity (90% CL) SK1 SK 3/4 300 kton WC 200 kton WC 100 kton WC WC: ε 14%, requires high PMT coverage. BG 20 evts/mt yr LAr: Presumed to have 95%+ efficiency by de/dx track of K + Year 33

34 The problem is, many of the theore\cal bands keep on going... to at least. 34

35 By 2012 we should have a good idea of the size of θ 13. If θ 13 is not too small, the next step with neutrinos is to complete the 3x3 framework by observing δ CP. Neutrino factories would be spectacular in this regard, however they may not be ready soon. If sin 2 2θ 13 is < 0.01 they may be necessary. The first steps can be taken and can succeed with modest increases in beam flux and larger detectors. The large detectors (if underground) naturally provide great scien\fic value in par\cle astrophysics and nucleon decay, helping to merit the cost of the project. They should be designed with mul\ decade opera\on in mind. For long baseline neutrino oscilla\on, the detectors will have a minimum size required to accomplish the job, for a given beam. However, for the non accelerator topics, they should be as large as possible (or affordable, in money and \me). 35