The ISS Peter Dornan Imperial College London

16 March 2006P Dornan - MUTAC `atmospheric’`solar’ `cross/reactor’ Oscillation defined by 3 mixing angles,        phase  Neutrino Oscillation

16 March 2006P Dornan - MUTAC Where are we? from: Maltoni, Schwetz, Tortola, Valle (’04) Also know m 2 > m 1 from matter effects in the sun

16 March 2006P Dornan - MUTAC Unanswered – Oscillation Expts Is  23 maximal? How small is  13 ? CP Violation in the lepton sector? Mass hierarchy?  m 3 m 2 Is the MNS approach correct? CPT violation? The ultimate accuracy on the mixing angles and the mass differences  What accuracy is needed? (LSND? Sterile neutrino(s)? )

16 March 2006P Dornan - MUTAC The Precision Era - after T2K and Nova Around We shall have good measurements of   12,  23,  m 2 12,  m 2 23 Probably have a measurement of  13 Possibly know the mass hierarchy So can now plan for the ultimate neutrino measurements  Refine all parameters  Check consistency  Measure CP Violation This is the aim of the ISS

16 March 2006P Dornan - MUTAC Neutrino source – options: Second generation super-beam  CERN, FNAL, BNL, J-PARC II Beta-beam Neutrino Factory

16 March 2006P Dornan - MUTAC The International Scoping Study  International scoping study of a future Neutrino Factory and super-beam facility Motivation Organisation Status  Physics Group  Accelerator Group  Detector Group ISS: next steps

16 March 2006P Dornan - MUTAC ISS: motivation Neutrino Factory – prior to launch of ISS  Several studies at the turn of the century US Studies I, II, IIa ECFA/CERN Study NuFact-J Study established feasibility & R&D programme  MUCOOL, MICE, MERIT…. But there have been advances since then Also appreciation of the need for an integrated accelerator-detector-physics approach  and an international approach

16 March 2006P Dornan - MUTAC ISS: motivation Preparation for design study  Review physics case  Critical comparison of options  Review options for accelerator complex: Prepare concept-development and hardware-R&D roadmaps for design-study phase  Review options for neutrino-detection systems Emphasis: identify concept-development and hardware-R&D roadmaps for design-study phase  Establish the Cost Drivers & Optimize Physics/$ - where there are alternatives Absolute scientific value - where only one method

16 March 2006P Dornan - MUTAC ISS: organisation

16 March 2006P Dornan - MUTAC Meetings Plenary meetings to date:  CERN: 22 – 24 September 2005 Attendance: 92 Americas: 15Asia: 12Europe 65  KEK: 23 – 26 January 2006 Attendance: 67 Americas: 11Asia: 28Europe 28  RAL 25 – 28 April 2006 Attendance 70 Final Plenary Meeting Irvine, Aug 21 – 22 Just before NuFact06

16 March 2006P Dornan - MUTAC Physics Group Theory subgroup :  What is the new physics  Need to distinguish between alternative theories  Establish the case for high-precision, high-sensitivity neutrino- oscillation programme Phenomenological subgroup  Review models of neutrino oscillations  Identify measurables that distinguish them and assess the precision required Experimental subgroup:  Use realistic assumptions on the performance of accelerator and detector to: Evaluate performance of the super-beam, beta-beam and Neutrino Factory alone or in combination  Make meaningful comparisons Muon physics subgroup:  Lepton-flavour violating processes – clear synergy with neutrino oscillations – possibly the next major discovery

16 March 2006P Dornan - MUTAC Some Theoretical Ideas Quark-lepton complementarity  Intriguing Relations Coincidence fundamental  GUTs motivate relationships between the quark and lepton mixing matrices  Measurable relations  Need Precision

16 March 2006P Dornan - MUTAC Quark-lepton complementarity

16 March 2006P Dornan - MUTAC A Possible Neutrino Sum Rule

16 March 2006P Dornan - MUTAC T owards a performance comparison A Major Goal of the ISS  Now many options  Must be reduced if there is to be a realistic design for a ‘precision era’ neutrino facility Requires justifiable assumptions:  Accelerator: flux, energy spectrum  Detector: E thresh, E Res (background, x-sect. uncertainty…) and optimised facility (accelerator, baseline, & detectors) Already a very substantial amount of work

16 March 2006P Dornan - MUTAC Cases under Consideration  Off axis super-beam: T2HK taken as example  Plan to explore different options (essentially vary E and L)  Beta beam: Low  :  = 100 and L = 130 km  High flux (~10 18 decays per year) and high flux (10 19 dpy) High  :  = 350 and L = 700 km  High flux (~10 18 decays per year) and high flux (10 19 dpy)  Also Beta beam abd superbeam combination  Neutrino Factory Performance studied as a function of:  E and L  E thresh and E Res

16 March 2006P Dornan - MUTAC Sample - CP sensitivity v. sin 2 2  13 Work in progress But highlights the importance of  13 in defining a strategy Huber, Lindner, Rolinec, Winter

16 March 2006P Dornan - MUTAC CPT & the MNS Theory In the Quark sector the CP violation parameters are determined in many ways Can we do the same in the neutrino sector? With 3 flavours and CPT  CP violation related in e ->   ->  e ->  Needs tau modes Murayama

16 March 2006P Dornan - MUTAC Physics Report How important – gold, silver, platinum? In the ideal scenario should we measure e  →  e        →  e     Specifically - how important are the tau channels?

16 March 2006P Dornan - MUTAC Neutrino Factory: optimisation Study performance as a function of muon energy and baseline Detector:  100 kton, magnetised iron  Importance of threshold sensitivity Can trade muon energy against detector threshold and resolution

16 March 2006P Dornan - MUTAC Muon Physics & the Factory Intense muon beams are needed for muon physics Could be the place for the next major advance But - is a Factory suitable for muon experiments?

16 March 2006P Dornan - MUTAC ISS status: Accelerator Group Most work on -Factory Subsystems & subgroups  Proton driver  Target and capture  Front end Bunching and phase rotation Cooling  Acceleration  Decay ring

16 March 2006P Dornan - MUTAC Towards a Baseline -Factory RF Frequency: Baseline is 201 MHz Phase Rotation: Baseline is Neuffer bunched beam rotation Phase Rotation: Baseline RMS bunch length 2 ns Amount of Cooling: Baseline is 50 m Target: Baseline is Liquid Mercury Pion Collection: 20 T Solenoid Repetition Rate: 50 (Hz) Proton bunch structure: 4 bunches spaced by 16 μsec Proton energy: 5-15 (GeV) Final acceleration: No decision yet Storage Ring: Choice is site dependent

16 March 2006P Dornan - MUTAC ISS status: Detector Group Detector options and subgroups  Large water Cherenkov ISS activity focuses on consideration of R&D required:  Photo tubes  Front-end electronics  Liquid argon  Emulsion  Magnetic sampling calorimeter  Near detector Further instrumentation issues:  Flux, muon-polarisation measurement

16 March 2006P Dornan - MUTAC Detector Questions Which can effectively be magnetised? Iron calorimeter, Emulsion, Hybrid Emulsion-Scintillator, Totally active scintillator Liquid Argon?? How low can one reduce the threshold? Can the Detector be on the surface Which can identify taus? This must tie in with the relevance of gold, silver platinum Usefulness for non-oscillation physics Define the necessary R&D Programme

16 March 2006P Dornan - MUTAC Neutrino Factory Future Development Following ISS there needs to be a Design Study for a Neutrino Factory  It will need engineering effort  And therefore resources  Where can these come from? Funding Agencies, Labs, EU  At the BENE/ISS meeting tomorrow planning for a request to the EU FP7 programme will start But funding from this source will not come until mid-end 2007  Activity must start before then - it should start this year And maintain the momentum of the ISS study

16 March 2006P Dornan - MUTAC Era of sensitivity & precision Factory  Beam But Factory and  beam can be on same timescale as superbeam upgrades Timescale – the Challenges

16 March 2006P Dornan - MUTAC ISS – Summary The ISS was launched at NuFact05 and is now over half way through its one year programme  Conclude at NuFact06 and a report early fall It has demonstrated a strong desire to have an internationally coordinated effort for future neutrino research (c.f linear collider)  New ideas  Many clarifications It has brought together accelerator & detector scientists with their experimental and theoretical physics colleagues in a very productive way It has built up a momentum which must be used as a springboard for the next phase