Future Neutrino Projects Beyond 13M. Dierckxsens, UDIG 08 Sensivity to CPV: > 50% δ‐coverage...
Transcript of Future Neutrino Projects Beyond 13M. Dierckxsens, UDIG 08 Sensivity to CPV: > 50% δ‐coverage...
Future Neutrino Projects
Beyond θ13
Ed Kearns Boston University
October 28, 2008
If θ13 > 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 θ23 ≠ 45°
10/28/08 2 Ed Kearns ‐ ICFA Seminar 2008
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.
J‐PARC 0.75 MW (T2K) 1.66 MW
FNAL 0.4 MW (NuMI) 1.2‐2 MW
CERN 0.5 MW (CNGS) 4 MW (SPL)
Water Cherenkov 22.5 kton (SK) 300‐500 kton
Fine Grained 15 kton (NOνA) 50‐100 kton (LAr)
The experimental issues remains essen\ally the same as with the prior genera\on: look for CCQE νe, NC π0 serious BG, beam νe is irreducible. However, we now run with ν and an\‐ν and need large sta\s\cs.
10/28/08 3 Ed Kearns ‐ ICFA Seminar 2008
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.
atmos.
solar
CP viola\ng
CP conserving
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for an\‐neutrinos, sign of x and sin δcp is changed
CPV effect 3x larger at 2nd maximum than 1st
L = 1000 km
Spread increases with baseline
Neutrinos and An\‐neutrinos reverse places with hierarchy
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Use spectral informa\on or mul\ple experiments (baselines or reactor) to resolve degenerate solu\ons.
Observables:
€
P(ν µ →ν e )
€
P(ν µ →ν e )
hlp://j‐parc.jp/NP08/
T. Hasegawa NP08
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ν
48 × 50 × 50 meters 2 detector caverns 270 kton + 270 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)
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K. Kaneyuki NP08
Sensi\vity to CPV: ≈50% δ‐coverage (3σ) for sin22θ13 = 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
10/28/08 9 Ed Kearns ‐ ICFA Seminar 2008
• Measure both first and second maximum • S\ll 270 kton + 270 kton fiducial mass • Eliminates many degeneracies • Controls systema\c uncertainty. M. Ishitsuka et al., Phys.Rev.D72:033003,2005
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Neutr
ino F
lux
Osc. P
rob.
1st Maximum
2nd Maximum L ~ 1000 km
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F. Dufour NOW’08
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F. Dufour NOW’08
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Sensi\vity to CPV: > 70% δ‐coverage (3σ) for sin22θ13 > 0.01 ‐ 10 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
F. Dufou
r NOW’08
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T. Maruyama – NP08
Kamioka 295 km 2.5° OA 0.6 GeV (1st) 0.2 GeV (2nd)
Okinoshima 650 km 0.8° OA 1.3 GeV (1st) 0.4 GeV (2nd)
A new possibility under inves\ga\on...
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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). 60 – 120 GeV protons fed by Project X. 300‐500 kton Water Cherenkov and/or ~100 kton LAr TPC.
Marciano, hep‐ph/0108181 Diwan et al., hep‐ex/0608023 Barger et al., arXiv:0705.4396
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M. Bishai, UDIG 08
120 GeV protons, 2.4 MW 0.5˚ OA Used for next plots
60 GeV protons, 1.2 MW 0˚ OA ⇒ comparable sensi\vi\es
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M. Dierckxsens, UDIG 08
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M. Dierckxsens, UDIG 08
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It is assumed that NC BG is completely removed for LAr. Remains to be demonstrated!
Water Cherenkov Liquid Argon
M. Dierckxsens, UDIG 08
Sensi\vity to CPV: > 50% δ‐coverage (3σ) for sin22θ13 > 0.015 ‐ 3+3 years running ‐ BG uncertainty = 5%; assume perfect BG rejec\on for LAr (80% signal efficiency)
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M. D
ierckxsens, U
DIG 08
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Eν (reco.) 1.7 GeV
proton 691 MeV/c
π0 1442 MeV/c
γ1 1204 MeV/c
γ2 245 MeV/c
Sensi\vity studies suggest a factor of 3‐6× in equivalent mass for LAr over WC.
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FLARE hep‐ex/0408121v1
LANNDD astro‐ph/0604548
GLACIER hep‐ph/0402110
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
World‐wide R&D effort Need long term demonstra\on of an opera\ng detector that generates physics results.
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Next Generation Water Cherenkov
Detector Configurations
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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.
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• 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
J. Campagne et al, JHEP 04 (2007) 003
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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
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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 νe and cooling tail of equal flavors.
May reveal fundamental neutrino physics as well: mass hierarchy via maler effects
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R. Tomas, et al. JCAP 0409, 015 2004
M. Nakahata et al.numbers for 1 Mton
(1) Neutroniza\on peak (2) Shock wave development
(3) Earth maler effects if >1 detector in world and some geometric luck
LAr can par\cipate too: νeCC (40Ar,40K*) 25000 νeCC events/380 neutroniza\on for 100 kt, 10kpc
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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?
~1015 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.
p
e+
π0 K+
ν ! ! !M4X
m5p
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Year
Life
time
Sens
itivi
ty (9
0% C
L)
SK3/4
SK2SK1
10 32
10 33
10 34
10 35
1995 2000 2005 2010 2015 2020 2025 2030 2035 2040
100 kton
200 kton
300 kton
+100 kton LAr
Sensi\vity versus \me for a plausible schedule for three 100 kton WC detectors followed by a 100 kton LAr TPC
Efficiency ~45% due to nuclear absorp\on of π0 (WC and LAr) Background from atmospheric neutrinos ~ 2 evts/Mt⋅yr Bright signature in WC, low PMT coverage should perform well.
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10 32
10 33
10 34
10 35
1995 2000 2005 2010 2015 2020 2025 2030 2035 2040
SK 3/4
Year
Life
time
Sens
itivi
ty (9
0% C
L)
SK1 100 kton WC200 kton WC
300 kton WC
+100 kton LAr
Sensi\vity versus \me for a plausible schedule for three 100 kton WC detectors followed by a 100 kton LAr TPC
WC: ε ∼14%, requires high PMT coverage. BG ∼ 20 evts/Mt⋅yr LAr: Presumed to have 95%+ efficiency by dE/dx track of K+
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The problem is, many of the theore\cal bands keep on going... to 1036 at least.
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By 2012 we should have a good idea of the size of θ13. If θ13 is not too small, the next step with neutrinos is to complete the 3x3
framework by observing δCP. Neutrino factories would be spectacular in this regard, however they
may not be ready soon. If sin22θ13 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).
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