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- M. A. Dı́az, M. Hirsch, Werner Porod, J. C. Romão, José W. F. Valle
- 2003

We give an analytical calculation of solar neutrino masses and mixing at one-loop order within bilinear R-parity breaking supersymmetry, and compare our results to the exact numerical calculation. Our method is based on a systematic perturbative expansion of R-parity violating vertices to leading order. We find in general quite good agreement between… (More)

The simplest unified extension of the Minimal Supersymmetric Standard Model with bi-linear R– Parity violation provides a predictive scheme for neutrino masses which can account for the observed atmospheric and solar neutrino anomalies in terms of bi-maximal neutrino mixing. The maximality of the atmospheric mixing angle arises dynamically, by minimizing… (More)

- Pran Nath, Brent D. Nelson, +12 authors J. C. Romão
- 2008

The Large Hadron Collider presents an unprecedented opportunity to probe the realm of new physics in the TeV region and shed light on some of the core unresolved issues of particle physics. These include the nature of electroweak symmetry breaking, the origin of mass, the possible constituent of cold dark matter, new sources of CP violation needed to… (More)

- Marco A. Dı́az, J. C. Romão, José W. F. Valle
- 1998

We show that the minimal R-parity breaking model characterized by an effective bilinear violation of R-parity in the superpotential is consistent with minimal N=1 supergravity unification with radiative breaking of the electroweak symmetry and universal scalar and gaugino masses. This one-parameter extension of the MSSMSUGRA model provides therefore the… (More)

S. Morisi, ∗ D. V. Forero, † J. C. Romão, ‡ and J. W. F. Valle § Institut für Theoretische Physik und Astrophysik, Universität Würzburg, 97074 Würzburg, Germany Departamento de F́ısica and CFTP, Instituto Superior Técnico Technical University of Lisbon,1049-001 Lisboa, Portugal AHEP Group, Institut de F́ısica Corpuscular – C.S.I.C./Universitat de València… (More)

- Michal Malinský, J. C. Romão, José. W. F. Valle
- Physical review letters
- 2005

We propose a new seesaw mechanism for neutrino masses within a class of supersymmetric SO(10) models with broken D parity. It is shown that in such scenarios the B-L scale can be as low as TeV without generating inconsistencies with gauge coupling unification nor with the required magnitude of the light neutrino masses. This leads to a possibly light new… (More)

- C Arina, Federica Bazzocchi, Nicolao Fornengo, J. C. Romão, José. W. F. Valle
- Physical review letters
- 2008

We show that within the inverse seesaw mechanism for generating neutrino masses, minimal supergravity naturally provides the scalar neutrino as the lightest superparticle. We also demonstrate that such schemes naturally reconcile the small neutrino masses with the correct relic scalar neutrino dark matter abundance and accessible direct detection rates in… (More)

- Werner Porod, M. Hirsch, J. C. Romão
- 2008

Low energy supersymmetry with bilinear breaking of R-parity leads to a weak-scale seesaw mechanism for the atmospheric neutrino scale and a radiative mechanism for the solar neutrino scale. The model has striking implications for collider searches of supersymmetric particles. Assuming that the lightest SUSY particle is the lightest neutralino we demonstrate… (More)

We study the possibilities of spontaneous CP violation in the Next-to-Minimal Supersymmetric Standard Model with an extra singlet tadpole term in the scalar potential. We calculate the Higgs boson masses and couplings with radiative corrections including dominant two loop terms. We show that it is possible to satisfy the LEP constraints on the Higgs boson… (More)

- M. Hirsch, J. C. Romão, S. Skadhauge, José W. F. Valle
- 2003

Recently Babu, Ma and Valle proposed a model of quark and lepton mixing based on A4 symmetry[1]. Within this model the lepton and slepton mixings are intimately related. We perform a numerical study in order to derive the slepton masses and mixings in agreement with present data from neutrino physics. We show that, starting from three-fold degeneracy of the… (More)