Bayesian evidence for non-zero theta(13) and CP-violation in neutrino oscillations
2012 (English)In: Journal of High Energy Physics (JHEP), ISSN 1029-8479, E-ISSN 1126-6708, Vol. 2012, no 8, 163- p.Article in journal (Refereed) Published
We present the Bayesian method for evaluating the evidence for a non-zero value of the leptonic mixing angle theta(13) and CP-violation in neutrino oscillation experiments. This is an application of the well-established method of Bayesian model selection, of which we give a concise and pedagogical overview. When comparing the hypothesis theta(13) = 0 with hypotheses where theta(13) > 0 using global data but excluding the recent reactor measurements, we obtain only a weak preference for a non-zero theta(13), even though the significance is over 3 sigma. We then add the reactor measurements one by one and show how the evidence for theta(13) > 0 quickly increases. When including the DOUBLE CHOOZ, DAYA BAY, and RENO data, the evidence becomes overwhelming with a posterior probability of the hypothesis theta(13) = 0 below 10(-11). Owing to the small amount of information on the CP-phase delta, very similar evidences are obtained for the CP-conserving and CP-violating hypotheses. Hence, there is, not unexpectedly, neither evidence for nor against leptonic CP-violation. However, when future experiments aiming to search for CP-violation have started taking data, this question will be of great importance and the method described here can be used as an important complement to standard analyses.
Place, publisher, year, edition, pages
2012. Vol. 2012, no 8, 163- p.
Neutrino physics, Statistical methods
IdentifiersURN: urn:nbn:se:kth:diva-103652DOI: 10.1007/JHEP08(2012)163ISI: 000309883200006ScopusID: 2-s2.0-84865742698OAI: oai:DiVA.org:kth-103652DiVA: diva2:561300
QC 201210182012-10-182012-10-172013-08-30Bibliographically approved