Proposal for a Supersymmetric Standard Model

The fact that neutrinos are massive suggests that the minimal supersymmetric standard model (MSSM) might be extended in order to include three gauge-singlet neutrino superfields with Yukawa couplings of the type $H_2 L \nu^c$. We propose to use these superfields to solve the $\mu$ problem of the MSSM without having to introduce an extra singlet superfield as in the case of the next-to-MSSM (NMSSM). In particular, terms of the type $\nu^c H_1 H_2$ in the superpotential may carry out this task spontaneously through sneutrino vacuum expectation values. In addition, terms of the type $(\nu^c)^3$ avoid the presence of axions and generate effective Majorana masses for neutrinos at the electroweak scale. On the other hand, these terms break lepton number and R-parity explicitly implying that the phenomenology of this model is very different from the one of the MSSM or NMSSM. For example, the usual neutralinos are now mixed with the neutrinos. For Dirac masses of the latter of order $10^{-4}$ GeV, eigenvalues reproducing the correct scale of neutrino masses are obtained.Comment: 9 pages, latex, title modified. Final version published in PR

Ammonia emissions from livestock production in Chile: an inventory and uncertainty analysis

Indexación: Web of Science; Scielo.The objective of this work was to quantify the country's NH3 emissions from livestock production. This calculation was based on the mass flow of total ammoniacal nitrogen (TAN). The analysis was performed for all 15 geographical regions in Chile. The definition of livestock subcategories was based on data from the Chilean Agriculture and Forestry Census as well as technical reports published by the Chilean National Statistics Institute. Significant differences were observed among the sources of livestock emissions in Chile's regions, and there was high variability depending on the degree of livestock confinement. In 2013, the total calculated emissions were 69.1 kt NH3/year (± 31.1). The O’Higgins Region had the highest NH3 emissions in Chile, representing 45% of the total. In terms of livestock production, 45% of the emissions were generated by pigs, 22% by poultry, 16% by cattle, 11% by equines and 4% by sheep. Emissions from the TAN that was available during manure and slurry management and the degree of animal confinement were the primary sources of uncertainty. This uncertainty could be greatly reduced by developing regional emission factors and by including the degree of animal confinement in Chile's national statistics such as the Agriculture, Livestock and Forestry Census.http://www.scielo.cl/scielo.php?pid=S0718-95162016005000005&script=sci_abstrac

Nonleptonic two-body B-decays including axial-vector mesons in the final state

We present a systematic study of exclusive charmless nonleptonic two-body B decays including axial-vector mesons in the final state. We calculate branching ratios of B\to PA, VA and AA decays, where A, V and P denote an axial-vector, a vector and a pseudoscalar meson, respectively. We assume naive factorization hypothesis and use the improved version of the nonrelativistic ISGW quark model for form factors in B\to A transitions. We include contributions that arise from the effective \Delta B=1 weak Hamiltonian H_{eff}. The respective factorized amplitude of these decays are explicitly showed and their penguin contributions are classified. We find that decays B^-to a_1^0\pi^-,\barB^0\to a_1^{\pm}\pi^{\mp}, B^-\to a_1^-\bar K^0, \bar B^0\to a_1^+K^-, \bar B^0\to f_1\bar K^0, B^-\to f_1K^-, B^-\to K_1^-(1400)\etap, B^-\to b_1^-\bar K^{0}, and \bar B^0\to b_1^+\pi^-(K^-) have branching ratios of the order of 10^{-5}. We also study the dependence of branching ratios for B \to K_1P(V,A) decays (K_1=K_1(1270),K_1(1400)) with respect to the mixing angle between K_A and K_B.Comment: 28 pages, 2 tables and one reference added, notation changed in appendices, some numerical results and abstract correcte

Optical Surface Photometry of a Sample of Disk Galaxies. II Structural Components

This work presents the structural decomposition of a sample of 11 disk galaxies, which span a range of different morphological types. The U, B, V, R, and I photometric information given in Paper I (color and color-index images and luminosity, ellipticity, and position-angle profiles) has been used to decide what types of components form the galaxies before carrying out the decomposition. We find and model such components as bulges, disks, bars, lenses and rings.Comment: 14 figures. Accepted for publication in A&

A geometrical analysis of the field equations in field theory

In this review paper we give a geometrical formulation of the field equations in the Lagrangian and Hamiltonian formalisms of classical field theories (of first order) in terms of multivector fields. This formulation enables us to discuss the existence and non-uniqueness of solutions, as well as their integrability.Comment: 14 pages. LaTeX file. This is a review paper based on previous works by the same author

Anatomical pathways for auditory memory II: information from rostral superior temporal gyrus to dorsolateral temporal pole and medial temporal cortex

Auditory recognition memory in non-human primates differs from recognition memory in other sensory systems. Monkeys learn the rule for visual and tactile delayed matching-to-sample within a few sessions, and then show one-trial recognition memory lasting 10–20 min. In contrast, monkeys require hundreds of sessions to master the rule for auditory recognition, and then show retention lasting no longer than 30–40 s. Moreover, unlike the severe effects of rhinal lesions on visual memory, such lesions have no effect on the monkeys' auditory memory performance. The anatomical pathways for auditory memory may differ from those in vision. Long-term visual recognition memory requires anatomical connections from the visual association area TE with areas 35 and 36 of the perirhinal cortex (PRC). We examined whether there is a similar anatomical route for auditory processing, or that poor auditory recognition memory may reflect the lack of such a pathway. Our hypothesis is that an auditory pathway for recognition memory originates in the higher order processing areas of the rostral superior temporal gyrus (rSTG), and then connects via the dorsolateral temporal pole to access the rhinal cortex of the medial temporal lobe. To test this, we placed retrograde (3% FB and 2% DY) and anterograde (10% BDA 10,000 mW) tracer injections in rSTG and the dorsolateral area 38DL of the temporal pole. Results showed that area 38DL receives dense projections from auditory association areas Ts1, TAa, TPO of the rSTG, from the rostral parabelt and, to a lesser extent, from areas Ts2-3 and PGa. In turn, area 38DL projects densely to area 35 of PRC, entorhinal cortex (EC), and to areas TH/TF of the posterior parahippocampal cortex. Significantly, this projection avoids most of area 36r/c of PRC. This anatomical arrangement may contribute to our understanding of the poor auditory memory of rhesus monkeys

Singular Lagrangian Systems on Jet Bundles

The jet bundle description of time-dependent mechanics is revisited. The constraint algorithm for singular Lagrangians is discussed and an exhaustive description of the constraint functions is given. By means of auxiliary connections we give a basis of constraint functions in the Lagrangian and Hamiltonian sides. An additional description of constraints is also given considering at the same time compatibility, stability and second-order condition problems. Finally, a classification of the constraints in first and second class is obtained using a cosymplectic geometry setting. Using the second class constraints, a Dirac bracket is introduced, extending the well-known construction by Dirac.Comment: 65 pages. LaTeX fil