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FUTURE NEUTRINO FACILITIES alain.blondel@cern.ch . Why future neutrino facilities ? Recently an american colleague having measured 13 was talking to hisfunding agency about a future neutrino project and was told :
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FUTURE NEUTRINO FACILITIES alain.blondel@cern.ch
Why future neutrino facilities ? Recently an americancolleaguehavingmeasured13wastalking to hisfundingagency about a future neutrino project and wastold: what more do youwant ? dont you know all these angles now? IMPORTANT TO STATE THE BIG PICTURE:
Neutrinos : the New Physics there is… and a lot of it! wrong Mass hierarchies are all unknownexcept m1 < m2 Preferred scenario has both Dirac and Majoranaterms … … manyphysicspossibilities and experimentalchallenges
Any of the following would be a fundamental breakthrough or discovery: Q.1 Determination of the absolute mass scale of neutrinos. Q.2 Determination of the mass hierarchy of the active neutrinos. Q.3 CP violation in neutrino oscillations. Q.4 Violation of unitarity of the neutrino mixing matrix. Q.5 Observation of fermion number violation by neutrinoless double beta decay. Q.6 Discovery of effects implying unambiguously the existence of sterile neutrino(s)
Present situation of neutrino mixing: • We know that there are three families of active, light neutrinos (LEP-1989) • 2. Solar neutrino oscillations are established • (Homestake+Gallium+Kamland+SK+SNO-1968-2002) • Atmospheric neutrino (nm -> ...) oscillations are established • (IMB+Kam+Macro+Sudan+SK) (1986-1998) • At the atmospheric frequency, electron neutrino oscillations are smaller (CHOOZ) • but not that small (T2K, MINOS, DoubleChooz, Daya Bay, Reno 2011-2012) • This allows a consistent picture with 3-family oscillations • preferred: • q12~300Dm122~8 10-5eV2 , q23~450, Dm232~ 2.5 10-3eV2, q13 = 90 • with several unknown parameters • => an exciting experimental program for at least 25 years *) • including leptonic CP & T violations 5. There is indication of possible higher frequency oscillations (LSND, miniBooNE, reactor, source anomaly) (1993-2011) This is not consistent with three families of active neutrinos oscillating, and is not supported (nor is it completely contradicted) by other experiments. This couldbe a series of unconvincingresultswithpoorexperimentalmethods… or a sign of the existence of light sterile neutrino(s)? *)to set the scale: CP violation in quarks was discovered in 1964 and there is still an important program (K0pi0, B-factories, Neutron EDM, BTeV, LHCb..) to go on for 10 years…(superB etc…) i.e. a total of ~60 yrs. and we have not discovered leptonic CP yet!
THE NEUTRINO MIXING MATRIX or Pontecorvo–Maki–Nakagawa–Sakata (PMNS) matrix From Wikipedia, the free encyclopedia: In particle physics, the Pontecorvo–Maki–Nakagawa–Sakata matrix (PMNS matrix), Maki–Nakagawa–Sakata matrix (MNS matrix), lepton mixing matrix, or neutrino mixing matrix, is a unitary matrix[note 1] which contains information on the mismatch of quantum states of leptons when they propagate freely and when they take part in the weak interactions. It is important in the understanding of neutrino oscillations. This matrix was introduced in 1962 by Ziro Maki, Masami Nakagawa and Shoichi Sakata,[1] to explain the neutrino oscillations predicted by Bruno Pontecorvo.[2][3]
Active neutrino mixingparameters: « naturalhierarchy » n3 Dm223= 2 10-3eV2 n2 n1 Dm212= 8 10-5 eV2 OR? « invertedhierarchy » n2 n1 Dm212= 8 10-5 eV2 Dm223= 2 10-3eV2 n3 q23(atmospheric) = 450 , q12(solar) = 320 , q13=90 Crucial roleplayed by 13! Next: phase , sign of Dm213 UPMNS 2
neutrino mixing m2n n3 n2 n1 neis a (quantum) mix of n1(majority, 65%) and n2 (minority 30%) with a small admixture of n3 ( < 13%) (CHOOZ)
13 Alain Blondel NUFACT12 23-07- 2012
Situation today: acceleratorbeam appearance : e reactoredisappearance Alain Blondel NUFACT12 23-07- 2012
Reactors Double Chooz sin2 2θ13=0.1090.03(stat) 0.025(sys) Daya Bay sin2 2θ13=0.089 0.010(stat) 0.005(sys) RENO sin2 2θ13 = 0.1130.013(stat) 0.019 (sys) sin2 2θ13 0.095 0.011 I believethatultimateprecisionwillbe 0.005 MINOS 2012 T2K 2012 MINOS very slight preference for m232<0… Alain Blondel NUFACT12 23-07- 2012
remarks Our colleagues of Dchoozhadit all right -- detector concept and design -- importance of two detectors for cancellation of systematics (L. Mikaelyan & V. Sinev) Disappearance and appearance are not the samething! -- wedon’t know intowhat doedisappear! (in the 3x3 unitarymixingit’s a nearlyequal mix of and ) -- even in 3x3 mixing the effects are different appearance directlymeasures e neutrino transition, CP violation by interference of atmospheric and solar oscillation mass hierarchythroughmattereffectsat long distances (level shift) disappearance at short distance (1.5km) pure 13-driven disappearance mass hierarchy via solar/atmosphericinterferencearound 50km atvery large distances (200km, KAMLAND) 12-driven disappearance Alain Blondel NUFACT12 23-07- 2012
This is the big neutrino news. We now know all three mixing angles! and the interplay of appearance and disappearance experiments will give us access to sign(m232) and to CP violation Meanwhile, IN ANOTHER WORLD…
While looking for the SM Higgs boson, LHC discovered a new boson! 2 expts 5 each
Sterile neutrinos Sterile neutrinos can have masses extending from (essentially 0) all the way to GUT-inspired 1010 GeV! We have many hints for ‘something that could be indications for sterile neutrinos ‘ in the ~ few eV2 range In general these hints are not performed with the desired methodological quality -- no near detector -- no direct flux measurement -- no long target hadroproduction with full acceptance -- etc.. etc… -- none is 5 sigma -- need decisive experiments (> 5 significance) -- look wide! other ranges than LSND ‘effect’ Alain Blondel NUFACT12 23-07- 2012
1989 The Number of light neutrinos ALEPH+DELPHI+L3+OPAL in 2001 N = 2.984 0.008 Error dominated by systematics on luminosity.
Thierry Lasserre Alain Blondel NUFACT12 23-07- 2012
Alain Blondel NUFACT12 23-07- 2012 Shaewitz Neutrino 2012
Sterile neutrino search a global view: Detected by mixing between sterile and active neutrino ideal experiments: source detector active, knownprocess knownprocess 1. disappearance, not necessarily oscillatory best is NC disappearance sterile 0. if sterile cannot be produced (too heavy) apparent deficit in decay rate active, 2. appearance (at higher order) Alain Blondel NUFACT12 23-07- 2012
Future experiments -- determination of mass hierarchy -- determination of CP violation or CP phase -- verification of 3x3 framework and search for sterile neutrinos
Oscillation maximum 1.27 Dm2 L / E =p/2 Atmospheric Dm 2= 2.5 10-3 eV 2 L = 500 km @ 1 GeV Solar Dm2 = 7 10-5 eV2 L = 18000km @ 1 GeV Oscillations of 250 MeV neutrinos; Consequences of 3-family oscillations: I There will be nm↔ ne and nt ↔ ne oscillation at L atm P (nm↔ ne)max =~ ½ sin 22 q13+… (small) II There will be CP or T violation CP: P (nm↔ ne) ≠ P (nm↔ ne) T : P (nm↔ ne) ≠ P (ne ↔nm) III we do not know if the neutrino n1 which contains more neis the lightest one (natural?) or not. P (nm↔ ne)
P(nenm) = ¦A¦2+¦S¦2 + 2 A S sin d P(nenm) = ¦A¦2+¦S¦2 - 2 A S sin d P(nenm) - P(nenm) sind sin (Dm212 L/4E) sin q12 sinq13 = ACP a sin2 2q13 + solar term… P(nenm) + P(nenm) … need large values of sin q12, Dm212 (LMA) but *not* large sin2q13 … need APPEARANCE … P(nene) is time reversal symmetric (reactors or sun are out) … can be large (30%) for suppressed channel (one small angle vs two large) at wavelength at which ‘solar’ = ‘atmospheric’ and for ne,t … asymmetry is opposite for neandnet
! large 13 asymmetry is a few % and requires excellent flux normalization (neutrino fact., beta beam or excellent near/far detector T asymmetry for sin = 1 asymmetry neutrino factory JHFII-HK asymmetrystatisticalerror NOTE: This isat first maximum! Sensitivityatlow values of q13isbetter for short baselines, sensitivityat large values of q13 maybebetter for longer baselines (2d max or 3d max.) 10 30 0.10 0.30 90
Latest Result of nm→nefrom T2K All the plots here are preliminary. 2.5x1020 POT Improvement of both reactor and accelerator experiments will provide first handle on the CP violating complex phase dCP. Stat err only! Expectation with ~50 times more data (750kWx 5x107s) Expected beam power
NOvA Alain Blondel NUFACT12 23-07- 2012
in some regions will be able to determine mass hierarchy at 3 in 6 years Alain Blondel NUFACT12 23-07- 2012
mass hierarchy with reactor? need resolution < separation between peaks <~ 2% at 3 MeV Alain Blondel NUFACT12 23-07- 2012
mass hierarchy with atmospherics? Alain Blondel NUFACT12 23-07- 2012
LBNO LArg LBNO- Lsc Alain Blondel NUFACT12 23-07- 2012 red =~ approved
Next n program at J-PARC Kamioka L=295km OA=2.5deg Okinoshima L=658km OA=0.78deg J-PARC 1.7MW 100kt Liq. Ar TPC P32 proposal (Lar TPC R&D) Recommended by J-PARC PAC (Jan 2010), arXiv:0804.2111 Hope to start construction ~2018
Tricky business… Lots of maybe’s and no definite assurance that with approved or non accelerator expts we will determine (i.e. 5) sign(m232) Should we propose a new definitive experiment? Some risk, so needs to be able to do CPV too… In the following I restrict to a European view given the upcoming upgrade of the European Strategy for particle physics Alain Blondel NUFACT12 23-07- 2012
Getting our feet on (under) the ground: LAGUNA –LBNO new FP7 design study 2011-2014 CERN EOI 2 main options Short distance: 130km Memphys at Frejus SPL+beta beam CP and T violation CN2PY Long distance: 2300km Pyhasalmi Fine grain detector e.g. 20kton fid. Larg + Magnetized detector Long distance allows rapid sensitivity to sign(m213) 1st step easier: SPS C2PY consortium 1st priority Nextsteps: HP 50 GeV PS … …or neutrino factory Medium term plans include long term plans!
CERN-SPSC-2012-021 (SPSC-EOI-007) aim at start date (2023) Alain Blondel NUFACT12 23-07- 2012
LBNO near detector 500m from target (> 100m underground) High pressure Ar gas TPC surrounded by TASD and MIND 100k events/year avoid pile-up and allows charge determination of electrons Alain Blondel NUFACT12 23-07- 2012
FAR DETECTOR Alain Blondel NUFACT12 23-07- 2012
1. rate dramatically affected by mass hierarchy. 5sigma in 2 years First goal of experiment both rate and spectrum of appearance sensitive to CPV longer term plans -- upgrade to stronger proton source -- upgrade to neutrino factory m232>0 m232<0 Alain Blondel NUFACT12 23-07- 2012
CERN-SPL-based Neutrino SUPERBEAM 300 MeV n m Neutrinos small contamination from ne (no K at 2 GeV!) target! Fréjus underground lab. A large underground water Cerenkov (400 kton) UNO/HyperK or/and a large L.Arg detector. also : proton decay search, supernovae events solar and atmospheric neutrinos. Performance similar to J-PARC II There is a window of opportunity for digging the cavern stating in 2008 (safety tunnel in Frejus)
CERN: b-beam baseline scenario Nuclear Physics neutrinos of Emax=~600MeV EU pride.. SPL target! Decay ring B = 5 T Lss = 2500 m SPS Decay Ring ISOL target & Ion source ECR Cyclotrons, linac or FFAG Stacking! Rapid cycling synchrotron PS Same detectors as Superbeam !
Combination of beta beam with low energy super beam Unique to CERN: need few 100 GeV accelerator (PS + SPS will do!) experience in radioactive beams at ISOLDE many unknowns: what is the duty factor that can be achieved? (needs < 10-3 ) combines CP and T violation tests e m (+) (T) m e (p+) (CP) e m (-) (T) m e (p-) Can this work???? theoretical studies now on beta beam + SPL target and horn R&D design study together with EURISOL
-- Neutrino Factory -- CERN layout -- cooling! 1016p/s target! acceleration! 1.2 1014 m/s =1.2 1021 m/yr _ 0.9 1021 m/yr m+ e+ne nm 3 1020 ne/yr 3 1020 nm/yr oscillates ne nm interacts givingm- WRONG SIGN MUON interacts giving m+