A Majorana neutrino is characterized by just one flavor diagonal electromagnetic form factor: the anapole moment, that in the static limit corresponds to the axial vector charge radius r 2 A . Experimental information on this quantity is scarce, especially in the case of the tau neutrino. We present a comprehensive analysis of the available data on the single photon production process e + e − → ννγ off Z-resonance, and we discuss the constraints that these measurements can set on r 2 A for the τ neutrino. We also derive limits for the Dirac case, when the presence of a vector charge radius r 2 V is allowed. Finally, we comment on additional experimental data on ν µ scattering from the NuTeV, E734, CCFR and CHARM-II collaborations, and estimate the limits implied for r 2 A and r 2 V for the muon neutrino.

Supersymmetric scenarios with R-parity conservation are becoming very constrained due to the lack of missing energy signals associated to heavy neutral particles, thus motivating scenarios with R-parity violation. In view of this, we consider a supersymmetric model with R-parity violation and extended by an anomalous horizontal U (1)H symmetry. A self-consistent framework with baryon-number violation is achieved along with a proper supression for lepton number violating dimension-5 operators, so that the proton can be sufficiently stable. With the introduction of righthanded neutrinos both Dirac and Majorana masses can be accommodated within this model. The implications for collider physics are discussed. I. INTRODUCTIONIn contrast to the standard model (SM), its supersymmetric version (SSM) does not have accidental lepton (L) and baryon-number (B) symmetries, and this can lead to major phenomenological problems, like fast proton decay. The standard solution to forbid all dangerous operators is the imposition of a discrete symmetry, like R-parity, and only in this minimal version (MSSM) the lightest supersymmetric particle (LSP), generally the neutralino, is stable, providing a good dark matter candidate. However, the recent results on searches for supersymmetry by CMS [1] and ATLAS [2] experiments have raised the bound on scalar and gluino masses, when they are approximately equal, to the order of 1.4 TeV for scenarios such as the R-parity conserving constrained minimal supersymmetric standard model (CMSSM). These searches are mainly based on missing transverse momentum carried by the LSP. A high mass scale for scalars and gluinos represents a potential chink in the initial proposal of the SSM as a possible solution to the hierarchy problem.However, these mass limits can be avoided in alternative supersymmetric models such as the R-parity violating SSM [3][4][5][6][7][8], where the LSP is usually assumed to be the gravitino which also provides a good decaying dark matter candidate [9,10]. The next to the lightest supersymmetric particle (NLSP) decays to standard model particles, and thus the missing transverse momentum may be considerably reduced [11][12][13][14][15][16][17][18]. In addition, if the involved couplings are small enough, the presence of displaced vertices may reduce the efficiency of the standard searches at LHC [11,18]. In particular, R-parity breaking scenarios with operators that violate B lead to the most difficult signals to be searched at hadron colliders [12][13][14][15][16][17]19]. The ad hoc choice of a discrete symmetry, like Lepton parity, to forbid all the L violating operators give rise to several issues. First, the size of the R-parity breaking couplings must be chosen precisely by hand in order to avoid constraints from flavor physics observables and other precision physics observables [8]. Second, dimension-5 L violating operators are automatically forbidden, and lepton-number violating neutrino mass terms cannot be generated at the renormalizable and nonrenormalizable level [20,2...

The Higgs potential and the mass spectrum of the N = 1 supersymmetric extension of a recently proposed one family model based on the local gauge group SU (3)C ⊗ SU (3)L ⊗ U (1)X , which is a subgroup of the electroweak-strong unification group E6, is analyzed. In this model the slepton multiplets play the role of the Higgs scalars and no Higgsinos are needed, with the consequence that the sneutrino, the selectron and six other sleptons play the role of the Goldstone bosons. We show how the µ problem is successfully addressed in the context of this model which also predicts the existence of a light CP-odd scalar.

El acceso abierto es un pilar fundamental para entender la comunicación científica de las últimas tres décadas, tanto a nivel mundial, pero especialmente desde América Latina. Su crecimiento, fundamentalmente a partir de la ruta dorada, ha generado cambios importantes en los modelos de negocio de la industria editorial científica. Uno de ellos ha venido con la aparición de los cobros por publicación (APC), lo cual se ha ido posicionando por el auge del acceso abierto y las políticas universitarias y gubernamentales para la evaluación de la investigación y los sistemas de recompensas. En este sentido, se ha hecho necesario reconocer las dinámicas asociadas a este fenómeno y atacar la falta de datos y la transparencia de los costos que implica el APC. Por ello, este artículo propone una metodología de seis pasos para analizar estos cobros en cualquier universidad, y presenta el panorama para el caso de las instituciones de educación superior colombianas. Se puede evidenciar el aumento de la producción científica en abierto a partir de la ruta dorada pero también el aumento de los gastos de las instituciones en los últimos años.

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