Schizophrenic active neutrinos and exotic sterile neutrinos

We implement a schizophrenic scenario for the active neutrinos in a model in which there are also exotic right-handed neutrinos making a model with a local U(1)_(B-L) anomaly free. Two of right-handed neutrinos carry B-L=-4 while the third one carries B-L=5.Comment: I, A. C. B. Machado, apologize for having submitted the wrong file before. This is in fact the version to be published in Physics Letters B 698 (2011) pp. 128-13

Comportamento produtivo de gramíneas forrageiras cultivadas sob sombreamento.

Publicado também em: MONTOYA VILCAHUAMAN, L. J.; RIBASKI, J.; MACHADO, A. M. B. (Ed.). Sistemas agroflorestais e desenvolvimento com proteção ambiental: práticas e tecnologias desenvolvidas. Colombo: Embrapa Florestas, 2006. p. 163-175

Investigating diffractive W production in hadron-hadron collisions at high energies

We compute the hard diffractive hadroproduction of bosons W at high energies using Regge factorization and taking into account multiple Pomeron exchange corrections. The ratio of diffractive to non-diffractive W production agrees with the current Tevatron data and a prediction for the LHC is presented.Comment: 4 pages, 1 table. To appear in the proceedings of 10th International Workshop on Hadron Physics (X Hadron Physics), Florianopolis, Brazil, 26-31 Mar 200

Neutrino structure functions in the QCD dipole picture

In this contribution we present an exploratory QCD analysis of the neutrino structure functions in charged current DIS using the color dipole formalism. The corresponding dipole cross sections are taken from recent phenomenological and theoretical studies in deep inelastic inclusive production, including nuclear shadowing corrections. The theoretical predictions are compared to the available experimental results in the small-x region.Comment: 4 pages, 2 figures. To appear in the proceedings of the XXXVI International Symposium on Multiparticle Dynamics. September 02-08, 2006 Paraty, Rio de Janeiro, Brazi

On a link between a species survival time in an evolution model and the Bessel distributions

We consider a stochastic model for species evolution. A new species is born at rate lambda and a species dies at rate mu. A random number, sampled from a given distribution F, is associated with each new species at the time of birth. Every time there is a death event, the species that is killed is the one with the smallest fitness. We consider the (random) survival time of a species with a given fitness f. We show that the survival time distribution depends crucially on whether ff_c where f_c is a critical fitness that is computed explicitly.Comment: 13 page