18.1k citations
Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.
- University of LisbonPT1.3k papers
- Universidade Técnica de LisboaPT388 papers
- Centre National de la Recherche ScientifiqueFR326 papers
- Instituto de Plasmas e Fusão NuclearPT209 papers
- European Organization for Nuclear ResearchCH202 papers
- Centro de Física Teórica de Partículas201 papers
- Instituto Politécnico de LisboaPT190 papers
- Instituto de TelecomunicaçõesPT175 papers
- Universitat de ValènciaES175 papers
- Institut National de Physique Nucléaire et de Physique des ParticulesFR143 papers
- Centro de Astrofísica e GravitaçãoPT133 papers
- LIP - Laboratory of Instrumentation and Experimental Particle PhysicsPT133 papers
25 papers · 2 filters
Charged-Lepton-Flavour Violation in the Light of the Super-Kamiokande Data
John Ellis, M. E. Gomez, G. K. Leontaris +2
Motivated by the data from Super-Kamiokande and elsewhere indicating oscillations of atmospheric and solar neutrinos, we study charged-lepton-flavour violation, in particular the r…
Scalar mesons as simple quark+antiquark states
Eef van Beveren, George Rupp
The Nijmegen Unitarized Meson Model and its application to scalar mesons is briefly revisited. It is shown that all scalar states up to 1.5 GeV can be described as triplet-P-zero q…
Linking solar and long baseline terrestrial neutrino experiments
E. Kh. Akhmedov, G. C. Branco, M. N. Rebelo
We show that in the framework of three light neutrino species with hierarchical masses and assuming no fine tuning between the entries of the neutrino mass matrix, one can use the…
Texture Zeros and Weak Basis Transformations
G. C. Branco, D. Emmanuel-Costa, R. Gonzalez Felipe
We investigate the physical meaning of some of the "texture zeros" which appear in most of the Ansatze on quark masses and mixings. It is shown that starting from arbitrary quark m…
Seesaw mechanism and structure of neutrino mass matrix
E. Kh. Akhmedov, G. C. Branco, M. N. Rebelo
We consider the seesaw mechanism of neutrino mass generation in the light of our present knowledge of the neutrino masses and mixing. We analyse the seesaw mechanism constrained by…
CPT violation and cascade decays
L. Lavoura
In tagged cascade decays of the type P^0 (P^0-bar) -> M^0 / M^0-bar X -> f X there are two complex CPT-violating parameters: one in P^0 - P^0-bar mixing, the other one in M^0 - M^0…
Comment on "New conditions for a total neutrino conversion in a medium"
E. Kh. Akhmedov, A. Yu. Smirnov
We show that the conditions for total neutrino conversion found in [1] are equivalent to the conditions of maximal depth (parametric resonance) and () - phase of parametr…
Small entries of neutrino mass matrices
E. Kh. Akhmedov
We consider phenomenologically allowed structures of the neutrino mass matrix in the case of three light neutrino species. Constraints from the solar, atmospheric and reactor neutr…
Real CP violation in a simple extension of the standard model
L. Lavoura
I present a simple three-Higgs-doublet extension of the standard model in which real CP violation takes place. The strong CP problem is attenuated by this model.
A new model for the quark mass matrices
L. Lavoura
I present a new model for the quark mass matrices, which uses four scalar doublets together with a horizontal symmetry S3 x Z3. The model is inspired on a suggestion made a few yea…
Parametric resonance in neutrino oscillations in matter
E. Kh. Akhmedov
Neutrino oscillations in matter can exhibit a specific resonance enhancement -- parametric resonance, which is different from the MSW resonance. Oscillations of atmospheric and sol…
Absorption and percolation in the production of J/psi in heavy ion collisions
J. Dias de Deus, R. Ugoccioni, A. Rodrigues
We present a simple model with string absorption and percolation to describe the J/psi suppression in heavy ion collisions. The NA50 data are fairly well explained by the model.
Cumulative particle production as a rare event
M. A. Braun, J. Dias de Deus, C. Pajares
The generalization of the Glauber formula for cumulative production events is derived. On its basis the multiplicity distribution in such events is related to the one in the minimu…
A Supersymmetric Solution to the Solar and Atmospheric Neutrino Problems
J. C. Romao, M. A. Diaz, M. Hirsch +2
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 fo…
Resonance spin flavour precession and solar neutrinos
J. Pulido, E. Kh. Akhmedov
We examine the prospects for the resonance spin flavour precession as a solution to the solar neutrino problem. We study seven different realistic solar magnetic field profiles and…
Angular Distribution and CP Asymmetries in the Decays B->K^-pi^+e^-e^+ and B->pi^-pi^+e^-e^+
F. Krüger, L. M. Sehgal, N. Sinha +1
The short-distance Hamiltonian describing b->s(d)e^-e^+ in the standard model is used to obtain the decay spectrum of \bar{B}->K^-pi^+e^-e^+ and \bar{B}->pi^-pi^+e^-e^+, assuming t…
Unification of gauge couplings and the tau neutrino mass in Supergravity without R-parity
M. A. Diaz, J. Ferrandis, J. C. Romao +1
Minimal R-parity violating supergravity predicts a value for smaller than in the case with conserved R-parity, and therefore closer to the experimental world average…
Large Neutrino Mixing with Universal Strength of Yukawa Couplings
G. C. Branco, M. N. Rebelo, J. I. Silva-Marcos
We analyse, within the framework of universal strength for Yukawa couplings (USY), various structures for the Dirac and Majorana neutrino mass matrices giving rise, through the see…
Leading nucleon and inelasticity in hadron-nucleus interactions
J. Bellandi, J. R. Fleitas, J. Dias de Deus
We present in this paper a calculation of the average proton-nucleus ine- lasticity. Using an Iterative Leading Particle Model and the Glauber model, we relate the leading particle…
Yukawa Structure with Maximal Predictability
G. C. Branco, D. Emmanuel-Costa, R. Gonzalez Felipe
A simple Ansatz for the quark mass matrices is considered, based on the assumption of a power structure for the matrix elements and the requirement of maximal predictability. A goo…
A Real CKM Matrix and Physics Beyond the Standard Model
G. C. Branco, F. Cagarrinho, F. Krüger
We study the possible existence of a real Cabibbo-Kobayashi-Maskawa (CKM) matrix, with CP violation originating from physics beyond the standard model (SM). We show that present ex…
Remarks on parametric resonance of neutrino oscillations in the earth
E. Kh. Akhmedov
Neutrino oscillations in matter can exhibit a specific resonance enhancement -- parametric resonance, which is different from the MSW resonance. Recently it has been shown that the…
Nucleosynthesis Constraints on a Scale-Dependent New Intermediate Range Interaction
O. Bertolami, F. M. Nunes
We derive constraints on the strength of a new intermediate range interaction that couples to baryon number from primordial nucleosynthesis yields. The nucleosysnthesis limits here…
Disentangling violations of CPT from other new-physics effects
L. Lavoura, Joao P. Silva
We analyze the prospects for observing CPT violation using neutral-meson P0-P0bar systems. Before one can claim a measurement of CPT violation, one must be able to rule out the pos…