Reassessing the sensitivity to leptonic CP violation
Abstract
We address the validity of the usual procedure to determine the sensitivity of neutrino oscillation experiments to CP violation. An explicit calibration of the test statistic is performed through Monte Carlo simulations for several experimental setups. We find that significant deviations from a χ ^{2} distribution with one degree of freedom occur for experimental setups with low sensitivity to δ. In particular, when the allowed region to which δ is constrained at a given confidence level is comparable to the whole allowed range, the cyclic nature of the variable manifests and the premises of Wilk's theorem are violated. This leads to values of the test statistic significantly lower than a χ ^{2} distribution at that confidence level. On the other hand, for facilities which can place better constraints on δ the cyclic nature of the variable is hidden and, as the potential of the facility improves, the values of the test statistics first become slightly higher than and then approach asymptotically a χ ^{2} distribution. The role of sign degeneracies is also discussed.
 Publication:

Journal of High Energy Physics
 Pub Date:
 March 2015
 DOI:
 10.1007/JHEP03(2015)005
 arXiv:
 arXiv:1407.3274
 Bibcode:
 2015JHEP...03..005B
 Keywords:

 Neutrino Physics;
 CP violation;
 Statistical Methods;
 High Energy Physics  Phenomenology;
 High Energy Physics  Experiment
 EPrint:
 14 pages, 5 figures, RevTeX4. The discussion of the results has been improved and considerably extended. Version accepted for publication in JHEP