La participación de los artesanos quiteños en la política ecuatoriana entre 1929 y 1933

Entre los años 1929 y 1933, en una época de transición histórica y de crisis económica y política, al final del reformismo juliano e inicios del velasquismo, los maestros de talleres artesanales quiteños organizados en sus gremios, y los aprendices, operarios y trabajadores autónomos en el marco de las organizaciones mutuales y en tránsito hacia las formas sindicales, ingresaron en la política nacional en medio de la multitud que ocupaba los espacios públicos. Construyeron una agenda política que recogió sus demandas específicas y las aspiraciones, visiones y mentalidad de los distintos sectores. Interpelaron al Estado y a las élites y enfrentaron al poder utilizando variadas formas de lucha: asambleas, peticiones y demandas a las autoridades; participación en elecciones locales y nacionales; movilizaciones, paros, huelgas parciales y generales y resistencia armada. De esta manera,contribuyeron al proceso de formación histórica de la clase obrera ecuatoriana

Dissecting the ΔI=1/2\Delta I= 1/2 rule at large NcN_c

We study the scaling of kaon decay amplitudes with the number of colours, $N_c$, in a theory with four degenerate flavours, $N_f=4$. In this scenario, two current-current operators, $Q^\pm$, mediate $\Delta S=1$ transitions, such as the two isospin amplitudes of non-leptonic kaon decays for $K\to (\pi\pi)_{I=0,2}$, $A_0$ and $A_2$. In particular, we concentrate on the simpler $K\to\pi$ amplitudes, $A^\pm$, mediated by these two operators. A diagrammatic analysis of the large-$N_c$ scaling of these observables is presented, which demonstrates the anticorrelation of the leading ${\mathcal O}(1/N_c)$ and ${\mathcal O}(N_f/N_c^2)$ corrections in both amplitudes. Using our new $N_f=4$ and previous quenched data, we confirm this expectation and show that these corrections are $naturally$ large and may be at the origin of the $\Delta I=1/2$ rule. The evidence for the latter is indirect, based on the matching of the amplitudes to their prediction in Chiral Perturbation Theory, from which the LO low-energy couplings of the chiral weak Hamiltonian, $g^\pm$, can be determined. A NLO estimate of the $K \to (\pi\pi)_{I=0,2}$ isospin amplitudes can then be derived, which is in good agreement with the experimental value.Comment: 12 pages, 7 figures. Minor change

Implementing the three-particle quantization condition including higher partial waves

We present an implementation of the relativistic three-particle quantization condition including both $s$- and $d$-wave two-particle channels. For this, we develop a systematic expansion about threshold of the three-particle divergence-free K matrix, $\mathcal{K}_{\mathrm{df,3}}$, which is a generalization of the effective range expansion of the two-particle K matrix, $\mathcal{K}_2$. Relativistic invariance plays an important role in this expansion. We find that $d$-wave two-particle channels enter first at quadratic order. We explain how to implement the resulting multichannel quantization condition, and present several examples of its application. We derive the leading dependence of the threshold three-particle state on the two-particle $d$-wave scattering amplitude, and use this to test our implementation. We show how strong two-particle $d$-wave interactions can lead to significant effects on the finite-volume three-particle spectrum, including the possibility of a generalized three-particle Efimov-like bound state. We also explore the application to the $3\pi^+$ system, which is accessible to lattice QCD simulations, where we study the sensitivity of the spectrum to the components of $\mathcal{K}_{\mathrm{df,3}}$. Finally, we investigate the circumstances under which the quantization condition has unphysical solutions.Comment: 57 pages, 12 figures, 3 tables (v2: Made minor clarifications, updated a reference, fixed typos

Generalizing the relativistic quantization condition to include all three-pion isospin channels

We present a generalization of the relativistic, finite-volume, three-particle quantization condition for non-identical pions in isosymmetric QCD. The resulting formalism allows one to use discrete finite-volume energies, determined using lattice QCD, to constrain scattering amplitudes for all possible values of two- and three-pion isospin. As for the case of identical pions considered previously, the result splits into two steps: The first defines a non-perturbative function with roots equal to the allowed energies, $E_n(L)$, in a given cubic volume with side-length $L$. This function depends on an intermediate three-body quantity, denoted $\mathcal{K}_{\mathrm{df},3}$, which can thus be constrained from lattice QCD input. The second step is a set of integral equations relating $\mathcal{K}_{\mathrm{df},3}$ to the physical scattering amplitude, $\mathcal M_3$. Both of the key relations, $E_n(L) \leftrightarrow \mathcal{K}_{\mathrm{df},3}$ and $\mathcal{K}_{\mathrm{df},3}\leftrightarrow \mathcal M_3$, are shown to be block-diagonal in the basis of definite three-pion isospin, $I_{\pi \pi \pi}$, so that one in fact recovers four independent relations, corresponding to $I_{\pi \pi \pi}=0,1,2,3$. We also provide the generalized threshold expansion of $\mathcal{K}_{\mathrm{df},3}$ for all channels, as well as parameterizations for all three-pion resonances present for $I_{\pi\pi\pi}=0$ and $I_{\pi\pi\pi}=1$. As an example of the utility of the generalized formalism, we present a toy implementation of the quantization condition for $I_{\pi\pi\pi}=0$, focusing on the quantum numbers of the $\omega$ and $h_1$ resonances.Comment: 46 pages, 4 figures. Updated to match erratum published in JHEP. Main conclusions and results unchange

The Large NcN_c limit of QCD on the lattice

We review recent progress in the study of the large $N_c$ limit of gauge theories from lattice simulations. The focus is not only the planar limit but also the size of ${\mathcal O}(N_c^{-1})$ corrections for values of $N_c\gtrsim 3$. Some concrete examples of the topics we include are tests of large-$N_c$ factorization, the topological susceptibility, the glueball, meson and baryon spectra, the chiral dependence of masses and decay constants, and weak matrix elements related to the $\Delta I=1/2$ rule in kaon decays.Comment: Contribution to the EPJA special issue "Lattice Field Theory during the COVID-19 pandemic". 19 pages, 17 figures, 1 table. Accepted in EPJA. Minor formatting issue fixe

«Dios, patria y libertad»: artesanos quiteños y política 1929-1933

Entre los años 1929 y 1933, los maestros, los operarios y los aprendices de los talleres artesanales quiteños ingresaron en la política nacional en medio de la multitud que ocupaba los espacios públicos. Construyeron una agenda política con demandas específicas y generales para expresar su identidad y sus aspiraciones. Utilizaron diversas formas de lucha, como asambleas, peticiones y demandas a las autoridades; y participaron en elecciones locales y nacionales, movilizaciones, huelgas parciales, huelgas generales y la acción armada para interpelar a las élites y enfrentarse al Estado. Así contribuyeron al proceso de formación histórica de la clase obrera ecuatoriana. Aquí unas páginas sobre esta historia, escritas en diálogo con periódicos de la época, hojas volantes y otros documentos, contestimonios de testigos y con los aportes realizados por quienes se han ocupado del tema, desde la historia y otras ciencias sociales

Kaon decays and other hadronic processes in lattice QCD

This doctoral thesis deals with the study of properties and interactions of light mesons. More specifically, we focus on hadronic decay and scattering processes, which are dominated by effects of the strong interaction in the low-energy regime. Concrete examples that will be addressed are the weak decay of a kaon into two pions, and the scattering of three pions. A peculiarity of the strong interaction is that perturbative expansions fail at hadronic energy scales. For this reason, genuine nonperturbative tools are essential to obtain first-principles predictions. The central technique employed in this work is Lattice Field Theory, which uses a discretized spacetime to stochastically estimate physical quantities in a quantum field theory. We will also make use of Effective Field Theories, as they provide a complementary description to the dynamics of light hadrons. The mathematical formulation of the strong interaction—Quantum Chromodynamics (QCD)—and the methods to resolve its dynamics will be addressed in Chapter 1. The original research of this dissertation is divided in two parts, each with a dedicated chapter. Chapter 2 describes our study of the ’t Hooft limit of QCD using lattice simulations, while in Chapter 3 we consider processes that involve multiparticle states. The ’t Hooft limit provides a simplification of nonabelian gauge theories that leads to precise nonperturbative predictions. We will analyze the scaling with the number of colours of various observables, such as meson masses, decay constants and weak transition matrix elements. An important question we address is the origin of the long-standing puzzle of the Delta I = 1/2 rule, that is, the large hierarchy in the isospin amplitudes of the K to pipi weak decay. This is an example in which the ’t Hooft limit seems to fail. Regarding multiparticle processes, we will discuss generalizations of the well-established L¨uscher formalism to explore three-particle processes from lattice simulations. The focus will be on the highlights of our contribution, such as our implementation of the finite-volume formalism that includeshigher partial waves, and the first application of the formalism to a full lattice QCD spectrum. We will also comment on the extension of the approach to generic three-pion systems. These will enable lattice explorations of scattering processes in some resonant channels, as well as phenomenologically interesting decays to three pions. A detailed summary in Spanish of the motivations, methodology, results and achievements of this thesis will be given in Chapter 4. The final part of the thesis (Part II) includes the peer-reviewed publications that constitute the body of this dissertation. Their original published form has been kept

Instrumentos de medida sobre autoeficacia percibida por el profesorado para prevenir o tratar el bullying.

Este trabajo es una revisión bibliográfica para hallar respuesta a la pregunta: ¿existen instrumentos de medida para los profesores que sean capaces de evaluar su autoeficacia para prevenir o tratar el bullying?, al revolverla hallaremos, que características tiene la educación física para enfrentar el bullying, que capacidades creen tener los profesores y que instrumentos existen en la literatura

Progress report on the relativistic three-particle quantization condition

We describe recent work on the relativistic three-particle quantization condition, generalizing and applying the original formalism of Hansen and Sharpe, and of Brice\~no, Hansen and Sharpe. In particular, we sketch three recent developments: the generalization of the formalism to include K-matrix poles; the numerical implementation of the quantization condition in the isotropic approximation; and ongoing work extending the description of the three-particle divergence-free K matrix beyond the isotropic approximation.Comment: 7 pages, 1 figure, Proceedings of Lattice 201