Suchergebnisse

Journal of High Energy Physics 2015.7 (2015): 160 reproduced by permission of Scuola Internazionale Superiore di Studi Avanzati (SISSA) ; We study the constraints that electroweak precision data can impose, after the discovery of the Higgs boson by the LHC, on neutrinophilic two-Higgs-doublet models which comprise one extra SU(2) × U(1) doublet and a new symmetry, namely a spontaneously broken ℤ2 or a softly broken global U(1). In these models the extra Higgs doublet, via its very small vacuum expectation value, is the sole responsible for neutrino masses. We find that the model with a ℤ2 symmetry is basically ruled out by electroweak precision data, even if the model is slightly extended to include extra right-handed neutrinos, due to the presence of a very light scalar. While the other model is still perfectly viable, the parameter space is considerably constrained by current data, specially by the T parameter. In particular, the new charged and neutral scalars must have very similar masses ; It is a pleasure to acknowledge stimulating discussions with Enrico Bertuzzo. This work was supported by Fundaçao de Amparo à Pesquisa do Estado de Sao Paulo (FAPESP) and Conselho Nacional de Ciencia e Tecnologia (CNPq). RZF would like to thank the hospitality of the LPT-Orsay, where part of this work was completed. PM acknowledges partial support from the European Union FP7 ITN INVISIBLES (Marie Curie Actions, PITN-GA-2011-289442), and from the Spanish MINECO's "Centro de Excelencia Severo Ochoa" Programme under grant SEV-2012-0249