The η−η′\eta - \eta' Mixing Angle Revisited

The value of the $\eta - \eta'$ mixing angle $\theta_P$ is phenomenologically deduced from a rather exhaustive and up-to-date analysis of data including strong decays of tensor and higher-spin mesons, electromagnetic decays of vector and pseudoscalar mesons, $J/\psi$ decays into a vector and a pseudoscalar meson, and other transitions. A value of $\theta_P$ between $-17^\circ$ and $-13^\circ$ is consistent with all the present experimental evidence and the average $\theta_P=-15.5^\circ\pm 1.3^\circ$ seems to be favoured.Comment: 17 pages, LaTeX. 2 references added, some comments on Chiral Perturbation Theor

Mixing of eta-eta' Mesons in J/psi Decays into a Vector and a Pseudoscalar Meson

The octet-singlet mixing angle $\theta_P$ in the pseudoscalar meson nonet is deduced from the rich set of accurate data on $J/\psi$ decays into a vector and a pseudoscalar meson. Corrections due to non-ideal $\omega$-$\phi$ mixing have been included for the first time and turn out to be crucial to find $\theta_P = -16.9 \pm 1.7$ degrees, which is appreciably less negative than previous results coming from similar analyses.Comment: 9 pages, LaTeX, full postscript file available via anonymous ftp at ftp://ftp.ifae.es/preprint/ft/uabft412.p

Kpi form factors and final state interactions in D+ --> K- pi+ pi+ decays

We present a model for the decay D+ --> K- pi+ pi+. The weak interaction part of this reaction is described using the effective weak Hamiltonian in the factorisation approach. Hadronic final state interactions are taken into account through the Kpi scalar and vector form factors fulfilling analyticity, unitarity and chiral symmetry constraints. The model has only two free parameters that are fixed from experimental branching ratios. We show that the modulus and phase of the S wave thus obtained agree nicely with experiment up to 1.55 GeV. We perform Monte Carlo simulations to compare the predicted Dalitz plot with experimental analyses. Allowing for a global phase difference between the S and P waves of -65 degrees, the Dalitz plot of the D+ --> K- pi+ pi+ decay, the Kpi invariant mass spectra and the total branching ratio due to S-wave interactions are well reproduced.Comment: 24 pages, 4 figures, REVTeX style. A discussion on the isospin 2 component has been included. Two references added. Published in Phys. Rev.

Boron abundance and solar neutrino spectrum distortion

The presence of neutrinos from Boron decay in the flux observed on Earth is attested by the observation of their energy spectrum. Possible distortions of the spectrum investigated in current detectors are often interpreted in terms of evidence in favour or against various schemes of neutrino oscillations. We stress here that a distortion of the spectrum at high energies could also result from an increase in the ratio of neutrinos originating from ($^3$He+p) and $^8$B reactions. While a $^8$B neutrino depletion would contribute to this effect, an increase in the Hep contribution seems also needed to reproduce the preliminary data.Comment: 8 pages, 2 figures; abstract and introduction rewritten to match the conclusions bette

Insights on neutrino lensing

We discuss the gravitational lensing of neutrinos by astrophysical objects. Unlike photons, neutrinos can cross a stellar core; as a result, the lens quality improves. We also estimate the depletion of the neutrino flux after crossing a massive object and the signal amplification expected. While Uranians alone would benefit from this effect in the Sun, similar effects could be considered for binary systems.Comment: 15 pages, 4 figures, to be published in Phys. Lett.

Aprendizaje significativo del concepto de gen entre estudiantes de biología. OPEL-IPC Venezuela

El gen es un conocimiento biológico abstracto y fundamental que se presenta como entidades físicas con funciones específicas y como conocimiento exacto y ahistórico Su tratamiento estructuralista y funcionalista es un obstáculo epistemológico (Bachelard, 1971; El-Hanny, 2005). La intervención didáctica pretendió propiciar un aprendizaje significativo crítico (Moreira,2005). Investigación interpretativa micro-etnográfica con 50 sujetos. Interpreta significados que se construyen en: Biología Celular y Genética General, La Intervención analiza lo que acontece en el aula (Ausubel, 2002). Los resultados corresponden con trabajos previos (Stotz, et al, 2004). Existen diferencias significativas a su favor, con espacios para analizar significados, su historia y epistemología

Aprendizaje significativo del concepto de gen entre estudiantes de biología. OPEL-IPC Venezuela

El gen es un conocimiento biológico abstracto y fundamental que se presenta como entidades físicas con funciones específicas y como conocimiento exacto y ahistórico Su tratamiento estructuralista y funcionalista es un obstáculo epistemológico (Bachelard, 1971; El-Hanny, 2005). La intervención didáctica pretendió propiciar un aprendizaje significativo crítico (Moreira,2005). Investigación interpretativa micro-etnográfica con 50 sujetos. Interpreta significados que se construyen en: Biología Celular y Genética General, La Intervención analiza lo que acontece en el aula (Ausubel, 2002). Los resultados corresponden con trabajos previos (Stotz, et al, 2004). Existen diferencias significativas a su favor, con espacios para analizar significados, su historia y epistemología

Effects of the electrostatic environment on superlattice Majorana nanowires

Finding ways of creating, measuring, and manipulating Majorana bound states (MBSs) in superconducting-semiconducting nanowires is a highly pursued goal in condensed matter physics. It was recently proposed that a periodic covering of the semiconducting nanowire with superconductor fingers would allow both gating and tuning the system into a topological phase while leaving room for a local detection of the MBS wave function. We perform a detailed, self-consistent numerical study of a three-dimensional (3D) model for a finite-length nanowire with a superconductor superlattice including the effect of the surrounding electrostatic environment, and taking into account the surface charge created at the semiconductor surface. We consider different experimental scenarios where the superlattice is on top or at the bottom of the nanowire with respect to a back gate. The analysis of the 3D electrostatic profile, the charge density, the low-energy spectrum, and the formation of MBSs reveals a rich phenomenology that depends on the nanowire parameters as well as on the superlattice dimensions and the external back-gate potential. The 3D environment turns out to be essential to correctly capture and understand the phase diagram of the system and the parameter regions where topological superconductivity is establishedWe thank E. J. H. Lee, H. Beidenkopf, E. G. Michel, N. Avraham, H. Shtrikman, and J. Nygård for valuable discussions. Research supported by the Spanish MINECO through Grants No. FIS2016-80434-P, No. BES-2017-080374, and No. FIS2017-84860-R (AEI/FEDER, EU), the European Union's Horizon 2020 research and innovation programme under the FETOPEN Grant Agreement No. 828948 and Grant Agreement LEGOTOP No. 788715, the Ramón y Cajal programme RYC-2011-09345, the María de Maeztu Programme for Units of Excellence in R&D (MDM-2014-0377), the DFG (CRC/Transregio 183, EI 519/7- 1), the Israel Science Foundation (ISF), and the Binational Science Foundation (BSF

Muon Anomalous Magnetic Moment and Lepton Flavor Violation

A non-universal interaction, which involves only the third family leptons induces lepton flavor violating couplings and contributes to the anomalous magnetic moment of muon. In this paper, we study the effects of non-universal interaction on muon (g-2) and rare decay $\tau \to \mu \gamma$ by using an effective lagrangian technique, and a phenomenological $Z^\prime$ model where $Z^\prime$ couples only to the third family lepton. We find that the deviation from the theory can be explained and the induced $\tau \to \mu \gamma$ rate could be very close to the current experimental limit. In the $Z^\prime$ model, $M_{Z^\prime}$ has to be lighter than 2.6 TeV.Comment: references added, the version to appear in PR