Future Neutrino Beam Facilities Pasquale Migliozzi INFN Napoli

Future Neutrino Beam Facilities Pasquale Migliozzi INFN - Napoli 1

The importance of pursuing neutrino oscillation studies n n Neutrino oscillations are the sole body of experimental evidence for physics beyond the Standard Model The observed tiny mass and the large flavour mixing are believed to be consequences of phenomena occurred at the Bing Bang n n Neutrino oscillation physics is complementary to high-energy collider physics The precision measurement of the oscillation parameters and the discovery of LCPV will have important consequences on astrophysics and cosmology Furthermore, if the presence of massive sterile neutrinos is proved (LSND-Mini. Boone saga), it will contribute to clarify the Dark Matter problem For a detailed discussion of these topics we refer to ar. Xiv: 0710. 4947 and references therein (The ISS Working Group); hep-ph/0606054 A. Strumia and F. Vissani

Constraints from a global 3 analysis M. C. Gonzalez-Garcia, M. Maltoni and J. Salvado, ``Updated global fit to three neutrino mixing: status of the hints of theta 13 > 0, '' ar. Xiv: 1001. 4524 [hep-ph]. Low-Z and SAGE meas. High-Z (<10%) ( 15%) ( 10%) ( 30%) θ 13 0 at 1. 9 θ 13 0 at 1. 5 Missing puzzle tiles: • determination of the θ 13 size: is it (almost) null? • sign of Δm 231: important for neutrinoless double beta-decay • CP violation in the leptonic sector: important for cosmology and astrophysics • More than 3 neutrinos?

How to complete the puzzle? n Three different approaches to build the next (or next-to-next) neutrino beam facilities are under study n n n Super-Beams Beta-Beams Neutrino Factory The pros and contra, the critical technical issues of each facility will be discussed in this talk Finally a conceptual and quantitative comparison of detector technologies, physics reach is also discussed

SUPER-BEAMS

Working Principle 1. High energy protons (O(10 Ge. V) to O(100 Ge. V) are sent onto a target (typically Be, graphite) where p and K are produced copiously 2. p+/K+ (p-/K-) are focused and p-/K- (p+/K+) are defocused in order to obtain a m (anti- m) beam through a magnetic lens system 3. Focused hadrons are let decay into a “decay tunnel” to produce neutrinos of the wanted flavor (and not only) 4. A shielding is put at the end of the decay tunnel in order to absorb charged particles associated with the neutrino beam (this step is only true for exps located very close (L<1 km) to the neutrino source) Can be very made very intense: more power (i. e. protons) on target makes more pions thus more neutrinos Small contamination of all n species: ultimately this contamination limits precision on q 13 and d measurements

Present and future facilities

High Power is a major issue Nu. Mi in 5 years, replaced both horns once, replaced target 4 times 3 target replacements linked to problems braising graphite to stainless steel water cooling tubes Extensive monitoring system provides ways to evaluate beamline conditions as problems arise

BETA-BEAMS

Working Principle

The ions

Physics requirements: top-down approach n Aiming at neutrino oscillation precise measurements and CP discovery in the leptonic sector, the requirements are: n Annual neutrino production n Beam load in RF cavities (ion bunching) n n 2. 9 x 1018 anti-nue from 6 He 1. 1 x 1018 nue from 18 Ne To suppress atmospheric neutrino background ions must be bunched This determines large transient beam load in RF NB More relevant for low Q ions Fast acceleration and efficient transmission Needed to avoid ion decay before the decay ring n Present CERN accelerator complex not optimized: With the present configuration less than 10% of Produced ions are stored in the decay ring! n

NEUTRINO FACTORY

Working Principle Neutrinos are produced from the decay in flight of muons All channels are available at a Neutrino Factory! The flux can be determined with a very high accuracy!

Two possible scenarios

Proton driver options • Challanges: high power; short proton bunch length at 10 Ge. V • Two possible solutions: both valid, but are site dependent • Linac: favourite at CERN and Fermilab • Rings: favourite at JPARC, RAL or “gree-field” option

Target/capture • Baseline: Hg jet, tapered solenoid shape (from 20 to 1. 5 T in 13 m) for pion capture • Alternatives: W bars or powder W jets The MERIT experiment @CERN proved the principle up to 8 MW

MICE experiment at RAL Muon front-end

DETECTOR TECHNIQUES

MIND: Magnetized Iron Neutrino Detector a suitable detector for Nu. Fact and High. Energy BB o o o Golden channel signature: appearance of “wrong-sign” muons in magnetised iron calorimeter 50 -100 m Far detector: 100 kton at 2000 -4000 km Magic detector: 50 kton at 7500 km Appearance of “wrong-sign” muons Segmentation: 3 cm Fe + 2 cm scintillator 1 T magnetic field beam 50 -100 k. T B=1 T detector iron (3 cm) 50% wrong 50% 15 m sign NUFACT 2010, TIFR, muon Mumbai , 22 October 2010 15 m + scintillators (RPC) Detector working principle at a Neutrino FActory

Totally Active Scintillator Detector (TASD) a suitable detector for LENu. Fact, Super-Beam and BB – – 35 kton 10, 000 modules 1000 cells per plane Total: 10 M channels 100 15 m 1. 5 cm 15 m m 3 cm o o o Momenta between 100 Me. V/c to 15 Ge. V/c Magnetic field considered: 0. 5 T Reconstructed position resolution ~ 4. 5 mm Reduction threshold: access second oscillation maximum and electron identification

Water Cerenkov a suitable technology for Super-Beam and BB o o USA, Europe, Japan: 100 -500 kt water Cherenkov detectors Technology well known from Super. K – but challenges in terms of size, cost, excavation, PMTs LBNE 300 kt Hyperkamiokande: ~550 kton (fiducial) MEMPHYS 65 m 440 kt or T 2 KK Kamioka+Korea 60 m

Liquid Argon technology suitable for all neutrino facilities o o Two different approaches Modular: Modu. LAr – 20 kton proposal at LNGS based m 2 Icarus modules o on larger 8 x 8 Glacier: – 50 -100 kton – Based on vertical drift – Readout: Large GEMs (LEM) Charge readout plane (LEM plane) GAr E ≈ 3 k. V/cm Glacier LAr racks Efield Extraction grid Electronic E≈ 1 k. V/cm Field shaping electrodes Cathode (- HV) UV & Cerenkov light readout PMTs

Nuclear Emulsion technology suitable for Nu. Fact and High. Energy. BB Emulsion Cloud Chamber (ECC) target spectrometer Shower absorber Electronic det: e/p/m separator & “Time stamp” stainless steel plate emulsion film Rohacell® plate This detector technology can be used to measure taus by searching for decay kink and measuring charge of decay

FACILITIES COMPARISON

Conceptual comparison Focus on that part q 13 MH CPV Dm 312 (indep. of q 13) q 23 Dm 212 q 12 Reactor X - SB X X BB X X X - NF X X - X (X LBL) - - - Taken from W. Winter @Nu. Fact 10

Quantitative comparison Best beta beam: Four ions, all at 1019 usef. decays/year g>350, 650 km (500 kt water)+ 7000 km (50 kt MIND) Theorists‘ dream? ? A Near detector would help + Systematics too conservative? + Detector re-opt. not included yet „Downgraded“ Nu. Fact ~ high end beta beam? Generation 3: Nu. Fact BB ? ? ? g>350 Generation 2: Probably LBNE not fantastic; T 2 HK cost? SPL BB 100? Generation 1: In Double Chooz construction Daya Bay will T 2 K happen! NOv. A

Conclusions n n n So far, neutrinos are the sole provider of physics beyond the Standard Model From 1998 to 2010 enormous steps have been put forward towards the understanding of neutrinos properties. A saga started in the first half of the XX century… From 2010 to 2020 precision measurements and the discovery of a non zero θ 13 will (we hope) be performed by experiment running at the existing neutrino facilities. Furthermore, the accelerator and detector R&D needed for the future facilities are being carried-on. From about 2020 the hunting for CP violation in the leptonic sector will start! Last but not least, possible sterile neutrinos and/or Non Standard Interactions should be also studied A lot of work is in front of us, but also a lot of fun!

… neutrinos induce courage in theoreticians and perseverance in experimenters Maurice Goldhaber, 1974 THANK YOU!