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
28 papers · 2 filters
D-state effects in the electromagnetic N-Delta transition
G. Ramalho, M. T. Pena, Franz Gross
We consider here a manifestly covariant quark model of the nucleon and the Delta, where one quark is off-shell and the other two quarks form an on-shell diquark pair. Using this mo…
Quasi-degenerate neutrinos and tri-bi-maximal mixing
Ivo de Medeiros Varzielas, Graham G. Ross, Mario Serna
We consider how, for quasi-degenerate neutrinos with tri-bi-maximal mixing at a high-energy scale, the mixing angles are affected by radiative running from high to low-energy scale…
Measuring Lepton Flavour Violation at LHC with Long-Lived Slepton in the Coannihilation Region
Satoru Kaneko, Joe Sato, Takashi Shimomura +2
When the mass difference between the lightest slepton, the NLSP, and the lightest neutralino, the LSP, is smaller than the tau mass, the lifetime of the lightest slepton increases…
Chiral symmetry breaking in the truncated Coulomb Gauge II. Non-confining power law potentials
P. Bicudo
In this paper we study the breaking of chiral symmetry with non-confining power-like potentials. The region of allowed exponents is identified and, after the previous study of conf…
Tri-bimaximal lepton mixing from symmetry only
W. Grimus, L. Lavoura
We construct a model for tri-bimaximal lepton mixing which employs only family symmetries and their soft breaking; neither vacuum alignment nor supersymmetry, extra dimensions, or…
Sterile Neutrinos in Light of Recent Cosmological and Oscillation Data: a Multi-Flavor Scheme Approach
Alessandro Melchiorri, Olga Mena, Sergio Palomares-Ruiz +3
Light sterile neutrinos might mix with the active ones and be copiously produced in the early Universe. In the present paper, a detailed multi-flavor analysis of sterile neutrino p…
A three-parameter neutrino mass matrix with maximal CP violation
W. Grimus, L. Lavoura
Using the seesaw mechanism, we construct a model for the light-neutrino Majorana mass matrix which yields trimaximal lepton mixing together with maximal CP violation and maximal at…
Discrete and continuous symmetries in multi-Higgs-doublet models
P. M. Ferreira, Joao P. Silva
We consider the Higgs sector of multi-Higgs-doublet models in the presence of simple symmetries relating the various fields. We construct basis invariant observables which may in p…
Building the full PMNS Matrix from six independent Majorana-type phases
Gustavo C. Branco, M. N. Rebelo
In the framework of three light Majorana neutrinos, we show how to reconstruct, through the use of 3 x 3 unitarity, the full PMNS matrix from six independent Majorana-type phases.…
A model for trimaximal lepton mixing
W. Grimus, L. Lavoura
We consider trimaximal lepton mixing, defined by |U_{alpha 2}|^2 = 1/3 for all alpha = e, mu, tau. This corresponds to a two-parameter lepton mixing matrix U. We present a model fo…
Study of psi' and chi_c decays as feed-down sources of J/psi hadro-production
P. Faccioli, C. Lourenco, J. Seixas +1
The interpretation of the J/psi suppression patterns observed in nuclear collisions, at CERN and RHIC, as a signature of the formation of a deconfined phase of QCD matter, requires…
Meson-meson interactions and Regge propagators
Eef van Beveren, George Rupp
By a reformulation of the loop expansion in the Resonance-Spectrum-Expansion amplitude for meson-meson scattering, in terms of s-channel exchange of families of propagator modes, w…
Three-flavour neutrino oscillation update
Thomas Schwetz, Mariam Tortola, Jose W. F. Valle
We review the present status of three-flavour neutrino oscillations, taking into account the latest available neutrino oscillation data presented at the Neutrino 2008 Conference. T…
Electromagnetic form factors of the Delta in a S-wave approach
G. Ramalho, M. T. Pena
Without any further adjusting of parameters, a relativistic constituent quark model, successful in the description of the data for the nucleon elastic form factors and of the domin…
Minimal supergravity sneutrino dark matter and inverse seesaw neutrino masses
C. Arina, F. Bazzocchi, N. Fornengo +2
We show that within the inverse seesaw mechanism for generating neutrino masses minimal supergravity is more likely to have a sneutrino as the lightest superparticle than the conve…
Nuclear like effects in proton-proton collisions at high energy
L. Cunqueiro, J. Dias de Deus, C. Pajares
We show that several effects considered nuclear effects are not nuclear in the sense that they do not only occur in nucleus-nucleus and hadron-nucleus collisions but, as well, they…
Microscopic calculation of the decay of Jaffe-Wilczek tetraquarks, and the Z(4433)
Marco Cardoso, Pedro Bicudo
Here the tetraquarks are studied a la Jaffe and Wilczek. The decay width is fully computed with a microscopic quark model, using the resonating group method.
Effect of Pions in Cosmic Rays
P. Castelo Ferreira, J. Dias de Deus
The effects of pions for vacuum polarization in background magnetic fields are considered. The effects of quark condensates is also briefly addresses. Although these effects are ou…
Chiral symmetry breaking beyond BCS and theorem on the width of scalars
P. Bicudo
We review chiral symmetry breaking at the BCS level, in the framework of chiral invariant quark models and in the Schwinger-Dyson formalism. We revisit the pi mass problem beyond t…
Probing minimal supergravity in the type-I seesaw mechanism with lepton flavour violation at the CERN LHC
M. Hirsch, W. Porod, J. C. Romao +2
The most general supersymmetric seesaw mechanism has too many parameters to be predictive and thus can not be excluded by any measurements of lepton flavour violating (LFV) process…
Reaction-diffusion processes in zero transverse dimensions as toy models for high-energy QCD
Nestor Armesto, Sergey Bondarenko, Jose Guilherme Milhano +1
We examine numerically different zero-dimensional reaction-diffusion processes as candidate toy models for high-energy QCD evolution. Of the models examined -- Reggeon Field Theory…
The oblique parameters in multi-Higgs-doublet models
W. Grimus, L. Lavoura, O. M. Ogreid +1
We present general expressions for the oblique parameters S, T, U, V, W, and X in the SU(2)xU(1) electroweak model with an arbitrary number of scalar SU(2) doublets, with hyperchar…
Chiral symmetry and excited baryons
A. V. Nefediev, J. E. F. T. Ribeiro, Adam P. Szczepaniak
An approach to baryons in the framework of the microscopic Generalized Nambu-Jona-Lasinio chiral potential quark model is considered and quite general arguments are given in favor…
Solving the Bethe-Salpeter equation for a pseudoscalar meson in Minkowski space
V. Sauli
A new method of solution of the Bethe-Salpeter equation for a pseudoscalar quark-antiquark bound state is proposed. With the help of an integral representation, the results are dir…