Future Neutrino Oscillation Experiments

1. Future Neutrino Oscillation Experiments PPAP Birmingham July 15th, 2009 Dave Wark Imperial/RAL

2. Predictions for Summer 2013... • England will be struggling in the Ashes... • T2K will have substantial data, Double-Chooz will be running with two detectors, Daya Bay and NOvA should be running... • By then we will have indications if q13 is “large” ( sin22q13 ≥ ~0.01) or not.

3. Four Different Ways Forward • Conventional Neutrino Beams I – Superer Beams • Higher power, bigger detector extrapolations of existing Superbeam projects like T2K or NOvA. • These exploit off-axis geometries to get narrow-band neutrino beams concentrated at the oscillation maximum. • Conventional Neutrino Beams II – WBBs • Use an on-axis geometry to get a wide-band beam from a conventional p-decay neutrino beam. • b-beams – derive pure ne(ne) beams from b (positron) decay of an unstable nucleus. • Neutrino Factory – mixed-flavour beam of neutrinos from m¯→ e¯+ ne + nm _ _

4. Three neutrino mixing. If neutrinos have mass: ~0.03 ~p/4

5. The q13 Fork. sin22q13> 0.01 sin22q13< 0.01 sin22q13 ≈ 0.01 • If sin22q13 ≥ ~0.01 there are sufficient events for conventional beams to potentially observe CP violation. • They are hampered by the impure nature of such beams. • If sin22q13 is smaller, then the fractional CP effect is larger, but conventional beams have no events left. • Must build a bB or a NF.

6. CP Reach of Various Projects.

7. Sensitivity To Mass Hierarchy

19. Interesting in conjunction with bB or NF?

20. sin22q13 Reach of Various Projects.

21. The EURISOL scenario Decay ring Br = 1500 Tm B = ~6 T C = ~6900 m Lss= ~2500 m 6He: g = 100 18Ne: g = 100 93 GeV 0.4 GeV 8.7 GeV Detector Requirements Similar to SB or WBB 1.7 GeV Design report July 2009 ! 21 New Opportunities in the Physics Landscape at CERN

22. t1/2 at rest (ground state) 1ms – 1s 1 – 60 s NuBase Choice of radioactive ion species 6He and 18Ne • Beta-active isotopes • Production rates • Life time • Reasonable life-time at rest • If too short: decay during acceleration • If too long: low neutrino production • Optimum life time given by acceleration scenario • In the order of a second (at rest) • Low Z preferred • Minimize ratio of accelerated mass/charges per neutrino produced • One ion produces one neutrino. • Reduce space charge problems 8Li and 8B EURISOL DS New Opportunities in the Physics Landscape at CERN

23. ISOL, 6He/18Ne and 8B/8Li 23 New Opportunities in the Physics Landscape at CERN • 6He • Tests of BeO at 3 kW at ISOLDE, analysis ongoing, encourageing! • 2 GeV, 200kW, on water-cooled W • 18Ne • To be studied (Frame-work, Priority?) • 4MW, 1 GeV on Hg? • Rotating/multiple targets/large beams (Ta, W)? • 8Li • Similarities with 6He: should be possible • To be measured • 8B • No beam ever produced • Many ideas exist. Need development (Frame-work, Priority?) • B is reactive (difficulties to get it out of the target)

24. The Neutrino Factory

25. Neutrino Factory Oscillation Channels • ne→ nm - the “Golden” Channel • Requires momentum and charge measurement of energetic muons – relatively straightforward. • nm→ nt - the “Silver” Channel • Requires clean detection of nt appearance events. • So far only emulsions – need a better technology (LAr?) • nm→ ne- the “Platinum” Channel • Requires charge measurement and NC background rejection for electron appearance. • LAr only technology so far identified for this. • Can also combine NF with SB, bB, Atm n, etc.

26. Other Important Points about Neutrino Factory • Only significant future facility with a semi-credible chance to be located in UK. • Like the SB, the UK has built a very significant international profile in the NF. • The NF is a way-station to a Muon Collider, which is the one facility which could re-unite the fragmented strands of our community behind a single project. • Should we stick to the NF? Obviously not.

27. Concluding Thoughts... • The physics is compelling, and must be a part of the future programme unless we abandon our goal of understanding all fundamental interactions (and abandon a significant fraction of the members of the field in the process). • There are currently too many options – we must further clarify both the technical and physics constraints (advances on q13 will be a key step). • We must pursue accelerator developments like MICE and MERIT to see what is really possible. • We must develop new detection technologies – I am not spending the next 15 years building a bigger version of MINOS which wastes most of the potential of the facility. • We must continue to build the UK community in order to maximize the return on our investments in T2K, MICE, etc.

28. My own view of where we should end up.... Will be confirmed by existing experiments. Next Generation: some variant on SB/WBB If... If... Ultimate: bB or NF, but in a while. Existing experiments will come up dry. If technical problems can be overcome. If detectors can take advantage of all opportunities. Build a Neutrino Factory next.