Transport properties of bottomed mesons in a hot mesonic gas

In this work we evaluate the B-meson drag and diffusion coefficients in a hot medium constituted of light mesons (pions, kaons and eta mesons). We treat the B-meson and B*-meson interaction with pseudo-Goldstone bosons in chiral perturbation theory at next-to-leading order within the constraints from heavy quark symmetry, and employ standard unitarization techniques of NLO amplitudes in order to account for dynamically generated resonances (leading to a more efficient heavy-flavor diffusion) and thus reach higher temperatures. We estimate individual meson contributions from the gas to the transport coefficients and perform a comparison with other findings in literature. We report a bottom relaxation length of about 80 fm at a temperature of 150 MeV and for typical momenta of 1 GeV, at which our approach is reliable. Compared to a charm relaxation length of 40 fm in the same conditions, we conclude that the B mesons provide a cleaner probe of the early stages of a heavy-ion collision.Comment: 14 pages, 16 figures, 3 tables. Version published in Phys.Rev.D87, 034019 (2013). Only minor improvements with respect to v1: corrected typos, further clarifications and updated reference

Heavy mesons in a hadronic medium: interaction and transport coefficients

We review the recent results of heavy meson diffusion in thermal hadronic matter. The interactions of D and B-bar mesons with other hadrons (light mesons and baryons) are extracted from effective field theories based on chiral and heavy-quark symmetries. When these guiding principles are combined with exact unitarity, physical values of the cross sections are obtained. These cross sections (which contain resonant contributions) are used to calculate the drag and diffusion coefficients of heavy mesons immersed in a thermal and dense medium. The transport coefficients are computed using a Fokker-Planck reduction of the Boltzmann equation.Comment: 4 pages, 3 figures. Contribution to the proceedings of the 15th International Conference on Strangeness in Quark Matter (SQM 2015), 06-11 Jul 2015. Dubna, Moscow region, Russi

The manifestation of intonational focus in Castilian Spanish

In this paper we study the phonological manifestation of various intonational focus domains in Castilian Spanish. We propose that downstep is one of the intonational signallers of focus in this language. The phonological problems of accounting for this phenomenon in Pierrehumbertian models are explored. Alternative solutions are offered following the single-tone model put forward by Cabrera Abreu (2000) within the Government Phonology framework, taking into account other proposals by the author and her co-workers. Typically, the prefocal and focal items participate in licensing relations which integrate them in a well-formed phonological structure in terms of onsets and nuclei respectively as the only two possible constituents within another major constituent, the intonation group. Pitch movements in the prefocal and focal items in the various focus domains are accounted for by the presence / absence of T(one) associated to different constituent boundaries. In addition, the constituent licensing the focal item is preceded by an intonation group whose nuclear constituent is empty, thus showing toneless boundaries which are responsible for the observed downstep effect.L'article presenta una anàlisi fonològica del focus entonatiu en castellà peninsular. Hom defensa que l'esglaonament descendent és un dels indicis acústics que marquen el focus en aquesta llengua. S'exploren els problemes fonològics per explicar aquest fenomen en el model mètric i autosegmental i s'ofereixen solucions alternatives seguint el model de to únic proposat per Cabrera Abreu (2000) en el marc de la fonologia de recció (tenint també en consideració altres propostes de l'autora i dels seus col·laboradors). Típicament, els elements prefocals i focals participen en relacions de legitimació que els integren en una estructura fonològica ben formada en termes d'inici i nucli respectivament dins un altre constituent major: el grup d'entonació. La realització entonativa dels elements prefocals i focals en els diferents dominis s'expliquen per la presència/ absència de to associat a diferents límits de constituents. El constituent que legitima l'element focal és precedit per un grup d'entonació amb un constituent nuclear buit, fent que els límits prosòdics sense to siguin responsables de l'efecte d'esglaonament descendent observat

D-meson diffusion in hadronic matter

We present effective-field-theory results with unitarized interactions on the D-meson transport coefficients in a gas populated by light mesons and baryons at finite temperature and baryochemical potential. The Fokker-Planck equation is used to compute the drag force, the relaxation time and the diffusion coefficients of D mesons for collisions at FAIR. At finite baryochemical potential, the combined effect of net baryonic density and sizable meson-baryon interaction makes the D mesons to relax more efficiently than in the case at zero baryochemical potential. We also describe the connection with the quark-gluon plasma phase in adiabatic trajectories on the phase diagram at both zero and finite baryochemical potential.Comment: 5 pages, 4 figures. Contribution to the FAIRNESS 2013 - Workshop for young scientists with research interests focused on FAIR physics. 15-21 September 2013, Berlin (Germany

La práctica en la formación inicial de docentes para Enseñanza Media en Uruguay. La perspectiva del profesorado adscriptor

La investigación tuvo como objetivo caracterizar la práctica docente, desde la perspectiva del profesorado adscriptor, en la formación inicial de docentes para Educación Media. Se realizó a partir de un estudio que abarcó al colectivo adscriptor de un Instituto de Formación Docente del interior del país, en el año 2017. A través de formularios on line, entrevistas y observación de una sala de coordinación, se identificó qué motivaciones lleva a este colectivo docente a asumir ese rol, cómo percibe a su estudiante practicante, las características de las actividades que se desarrollan en el ámbito de la práctica y los vínculos con los cursos de Didáctica y con la institución formadora. Además, se analizaron las situaciones problemáticas y las propuestas de mejora que perciben, en el ejercicio del rol. Los principales resultados presentaron un colectivo adscriptor relativamente joven en el ejercicio del rol, cuyas motivaciones pasan principalmente por su interés en crecer profesionalmente y en apoyar a los y las estudiantes en formación. En relación al nivel formativo de las actividades que se desarrollan en el ámbito de la práctica, se destacaron aquellas relacionadas directamente con el desempeño en el aula, y el posterior análisis e intercambio con otras personas de la institución de práctica, otros/as estudiantes y docentes de Didáctica. El colectivo se presenta en un rol aislado, con escasos vínculos con la institución formadora y con el cuerpo docente de Didáctica. En la solución de este aspecto es donde se concentran las principales demandas de cambio

The thermal width of heavy quarkonia moving in quark gluon plasma

The velocity dependence of the thermal width of heavy quarkonia traveling with respect to the quark gluon plasma is calculated up to the NLO in perturbative QCD. At the LO, the width decreases with increasing speed, whereas at the NLO it increases with a magnitude approximately proportional to the expectation value of the relative velocity between the quarkonium and a parton in thermal equilibrium. Such an asymptotic behavior is due to the NLO dissociation cross section converging to a nonvanishing value in the high energy limit.Comment: 8 pages, 4 figures, references addes. version to be published in Phys. Lett.