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Intermediate beta-beams with a cluster of detectors. Christopher Orme IPPP, Durham. EPS 2007, Manchester, July 19 th 2007. Overview of the talk. Goals for future oscillation experiments The Beta-beam Aims of our study Preliminary simulation results. Future Goals.
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Intermediate beta-beams with a cluster of detectors Christopher Orme IPPP, Durham EPS 2007, Manchester, July 19th 2007
Overview of the talk • Goals for future oscillation experiments • The Beta-beam • Aims of our study • Preliminary simulation results
Future Goals • Greater precision on parameters already measured • MINOS, OPERA and ICARUS, T2K + Solar and Atmos • Determine neutrino mass hierarchy • Use of matter effect • Synergies with ββ0ν • Models of neutrino mass and mixings • Obtain information on the unknown 13 and CP-violating δ • 13 close to current bounds → Superbeams + reactors • Smaller 13 → Neutrino factories and β-beams
Degeneracies • Sensitivity to oscillation parameters limited by fake solutions due to • Unknown mass hierarchy • Unknown 23 octant • “Intrinsic degeneracies” • Neutrino factory • L = 2810 km • 13 = 20, δ = 540 • Three fake solutions
The beta-beam • Accelerate radioactive isotopes • Intense, collimated, clean ν beam • Use of proposed or existing CERN facilities • EURISOL project, SPS upgrades • 18Ne and 6He standard choices • Noble gases prefered • Need low(ish) Z and lifetimes 1 sec Eν = 2E0
This study • Two baselines from same β-beam source • Strategy • Use CERN-Boulby (1050 km) and CERN-Canfranc (650 km) • Run with 18Ne at = 450 • Covers both 1st maxima • Decays scale as 1/ • Reduce backgrounds at higher energies
Setup • Considered single β+ emitter 18Ne • Addition of 8Li at low does not alter result • Energy binning • Both detectors assume threshold 400 MeV • 18Ne signal split into 11 bins (0.4,0.6), (0.6,0.8), …., (2.4,3.06) • Spectral information helps resolve intrinsic degeneracy • Statistics • Canfranc →2.5 x 1020 decays*kton*yr • Boulby → 5 x 1020 decays*kton*yr
Mass hierarchy • Canfranc and Boulby mostly compensate for each other • A lithium run does not improve the sensitivity • With 5 % systematics, degeneracy disappears down to 13 0.50
CP-violation (Preliminary) • Great sensitivity with a single channel • Location of clone different for each baseline – improves sensitivity • As with sign, degeneracy disappears down to 13 0.50
Conclusions • Degeneracies a problem for future LBL experiments • Considered two baselines with a single source to use same L/E strategy • With 5 % systematics, sensitivities down to 0.50 • A Phase II LBL experiment should utilise as many synergies as possible to maximise physics reach. A European network of detectors could realise this for the β-beam with upgraded SPS