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12 papers · 2 filters
CPT Violation and Baryogenesis
O. Bertolami, Don Colladay, V. Alan Kostelecký +1
We examine the effects on baryogenesis of spontaneous CPT violation in a string-based scenario. Under suitable circumstances, certain CPT-violating terms can produce a large baryon…
Single-Photon Z Decays and Small Neutrino Masses
J. C. Romao, S. D. Rindani, J. W. F. Valle
We discuss some rare Z decay signatures associated with extensions of the Standard Model with spontaneous lepton number violation at the electroweak scale. We show that single-phot…
Solution of the strong CP problem
L. Lavoura
I put forward an SU(2)_L x SU(2)_R x U(1) model in which spontaneously broken parity symmetry makes it that strong CP violation only arises at three-loop level. All leptons and up-…
Primordial Nucleosynthesis, Majorons and Heavy Tau Neutrinos
A. D. Dolgov, S. Pastor, J. C. Romao +1
We determine the restrictions imposed by primordial nucleosynthesis upon a heavy tau neutrino, in the presence of nu-tau annihilations into Majorons, as expected in a wide class of…
A New Approach to the Yukawa Puzzle
G. C. Branco, D. Emmanuel-Costa, J. I. Silva-Marcos
We do a systematic analysis of the question of calculability of CKM matrix elements in terms of quark mass ratios, within the framework of the hypothesis of universality of strengt…
Supersymmetric Unification with Radiative Breaking of R-parity
J. C. Romao, A. Ioannissyan, J. W. F. Valle
We show how R-parity can break spontaneously as a result of radiative corrections in unified N=1 supergravity models. We illustrate this with a concrete rank-four unified model, wh…