|
|
Cappiello, L., Cata, O., & D'Ambrosio, G. (2010). Antisymmetric tensors in holographic approaches to QCD. Phys. Rev. D, 82(9), 095008–13pp.
Abstract: We study real (massive) antisymmetric tensors of rank two in holographic models of QCD based on the gauge/string duality. Our aim is to understand in detail how the anti-de Sitter/conformal field theory correspondence describes correlators with tensor currents in QCD. To this end we study a set of bootstrapped correlators with spin-1 vector and tensor currents, imposing matching to QCD at the partonic level. We show that a consistent description of this set of correlators yields a very predictive picture. For instance, it imposes strong constraints on infrared boundary conditions and precludes the introduction of dilatonic backgrounds as a mechanism to achieve linear confinement. Additionally, correlators with tensor currents turn out to be especially sensitive to chiral symmetry breaking, thus offering an ideal testing ground for genuine QCD effects. Several phenomenological consequences are explored, such as the nontrivial interplay between 1(+-) states and conventional 1(--) vector mesons.
|
|
|
|
Hirsch, M., Kernreiter, T., Romao, J. C., & del Moral, A. V. (2010). Minimal supersymmetric inverse seesaw: neutrino masses, lepton flavour violation and LHC phenomenology. J. High Energy Phys., 01(1), 103–21pp.
Abstract: We study neutrino masses in the framework of the supersymmetric inverse seesaw model. Different from the non-supersymmetric version a minimal realization with just one pair of singlets is sufficient to explain all neutrino data. We compute the neutrino mass matrix up to 1-loop order and show how neutrino data can be described in terms of the model parameters. We then calculate rates for lepton flavour violating (LFV) processes, such as μ-> e gamma and chargino decays to singlet scalar neutrinos. The latter decays are potentially observable at the LHC and show a characteristic decay pattern dictated by the same parameters which generate the observed large neutrino angles.
|
|
|
|
Barragan, C., & Olmo, G. J. (2010). Isotropic and anisotropic bouncing cosmologies in Palatini gravity. Phys. Rev. D, 82(8), 084015–15pp.
Abstract: We study isotropic and anisotropic (Bianchi I) cosmologies in Palatini f(R) and f(R, R μnu R μnu) theories of gravity with a perfect fluid and consider the existence of nonsingular bouncing solutions in the early universe. We find that all f(R) models with isotropic bouncing solutions develop shear singularities in the anisotropic case. On the contrary, the simple quadratic model R + aR(2)/R-P + R μnu R μnu/R-P exhibits regular bouncing solutions in both isotropic and anisotropic cases for a wide range of equations of state, including dust (for a<0) and radiation (for arbitrary a). It thus represents a purely gravitational solution to the big bang singularity and anisotropy problems of general relativity without the need for exotic (w>1) sources of matter/energy or extra degrees of freedom.
|
|
|
|
Aguilar, A. C., Binosi, D., & Papavassiliou, J. (2010). Nonperturbative gluon and ghost propagators for d=3 Yang-Mills theory. Phys. Rev. D, 81(12), 125025–13pp.
Abstract: We study a manifestly gauge-invariant set of Schwinger-Dyson equations to determine the non-perturbative dynamics of the gluon and ghost propagators in d = 3 Yang-Mills theory. The use of the well-known Schwinger mechanism, in the Landau gauge leads to the dynamical generation of a mass for the gauge boson (gluon in d = 3), which, in turn, gives rise to an infrared finite gluon propagator and ghost dressing function. The propagators obtained from the numerical solution of these nonperturbative equations are in very good agreement with the results of SU(2) lattice simulations.
|
|
|
|
Lopez Honorez, L., Mena, O., & Panotopoulos, G. (2010). Higher-order coupled quintessence. Phys. Rev. D, 82(12), 123525–7pp.
Abstract: We study a coupled quintessence model in which the interaction with the dark-matter sector is a function of the quintessence potential. Such a coupling can arise from a field dependent mass term for the dark-matter field. The dynamical analysis of a standard quintessence potential coupled with the interaction explored here shows that the system possesses a late-time accelerated attractor. In light of these results, we perform a fit to the most recent Supernovae Ia, Cosmic Microwave Background, and Baryon Acoustic Oscillation data sets. Constraints arising from weak equivalence principle violation arguments are also discussed.
|
|
