We show that the neutrino mass matrix of the Zee-Babu model is able to fit the recent data on neutrino masses and mixing with non-zero θ13 in the inverted neutrino mass hierarchy. The results show that the Majorana phases are equal to zero and the Dirac phase (δ) is predicted to either 0 or π, i. e, there is no CP violation in the Zee-Babu model at the two loop level. The effective mass governing neutrinoless double beta decay and the sum of neutrino masses are consistent with the recent analysis | Communications in Physics, Vol. 25, No. 4 (2015), pp. 291-298 DOI: INVERTED NEUTRINO MASS HIERARCHY AND MIXING IN THE ZEE-BABU MODEL VO VAN VIEN Department of Physics, Tay Nguyen University, 567 Le Duan, Buon Ma Thuot, DakLak, Vietnam HOANG NGOC LONG Institute of Physics, VAST, 10 Dao Tan, Ba Dinh, Hanoi, Vietnam PHAM NGOC THU Faculty of Mathematics-Physics-Informatics, Tay Bac University, Son La city, Vietnam E-mail: wvienk16@ Received 29 November 2015 Accepted for publication 24 December 2015 Abstract. We show that the neutrino mass matrix of the Zee-Babu model is able to fit the recent data on neutrino masses and mixing with non-zero θ13 in the inverted neutrino mass hierarchy. The results show that the Majorana phases are equal to zero and the Dirac phase (δ ) is predicted to either 0 or π, i. e, there is no CP violation in the Zee-Babu model at the two loop level. The effective mass governing neutrinoless double beta decay and the sum of neutrino masses are consistent with the recent analysis. Keywords: neutrino mass and mixing, non-standard-model neutrinos, Zee-Babu model. I. INTRODUCTION At present, neutrino and Higgs physics are hot topics in Particle Physics. The neutrino mass and mixing are the first evidence of beyond Standard Model (SM) physics. Despite the Higgs boson has been discovered by the ATLAS [1] and the CMS [2] but to which model it belongs still an open question. For the aforementioned reasons, the search for an extended model coinciding with the current data on neutrino physics is one of our top priorities. In our opinion, the model with the simplest particle content is preferred. By this criterion, the Zee-Babu model [3–5] is very attractive. In our previous work [6], we have derived the exact solution for the neutrino mass matrix in the model under consideration and derived some regions of the parameters in the normal neutrino mass hierarchy. As far as we know at present the values of the absolute .
