Precision on leptonic mixing parameters at future neutrino oscillation experiments

Journal of High Energy Physics 2012.6 (2012): 73 reproduced by permission of Scuola Internazionale Superiore di Studi Avanzati (SISSA)We perform a comparison of the different future neutrino oscillation experiments based on the achievable precision in the determination of the fundamental parameters θ13 and the CP phase, δ assuming that θ13 is in the range indicated by the recent Daya Bay measurement. We study the non-trivial dependence of the error on δ on its true value. When matter effects are small, the largest error is found at the points where CP violation is maximal, and the smallest at the CP conserving points. The situation is different when matter effects are sizable. As a result of this effect, the comparison of the physics reach of different experiments on the basis of the CP discovery potential, as usually done, can be misleading. We have compared various proposed super-beam, beta-beam and neutrino factory setups on the basis of the relative precision of θ13 and the error on δ. Neutrino factories, both high-energy or low-energy, outperform alternative beam technologies. An ultimate precision on θ13 below 3% and an error on δ of ≥ 7° at 1σ (1 d.o.f.) can be obtained at a neutrino factoryPC would like to acknowledge useful discussions with Patrick Huber and Walter Winter, and would like to thank the support and hospitality of the Theory Division at CERN where part of this work was done. This work was partially supported by the Spanish Ministry for Education and Science projects FPA2007-60323, FPA2009-09017, FPA2011-29678; the Consolider-Ingenio CUP (CSD2008-00037) and CPAN (CSC2007-00042); the Generalitat Valenciana (PROMETEO/2009/116); the Comunidad Autónoma de Madrid (HEPHACOS P-ESP-00346 and HEPHACOS S2009/ESP-1473); the European projects EURONU (CE212372), EuCARD (European Coordination for Accelerator Research and Development, Grant Agreement number 227579), LAGUNA (Project Number 212343) and ITN INVISIBLES (Marie Curie Actions, PITN-GA-2011-289442). This work has been supported by the U.S. Department of Energy under award number DE-SC000391