Testing models with non-minimal Higgs sector through the decay t->q+WZ

We study the contribution of charged Higgs boson to the rare decay of the top quark t->q+WZ (q=d,s,b) in models with Higgs sector that includes doublets and triplets. Higgs doublets are needed to couple charged Higgs with quarks, whereas the Higgs triplets are required to generate the non-standard vertex HWZ at tree-level. It is found that within a model that respect the custodial SU(2) symmetry and avoids flavour changing neutral currents by imposing discrete symmetries, the decay mode t->b+WZ, can reach a branching ratio of order 0.0178, whereas the decay modes t->(d,s)+WZ, can reach a similar branching ratio in models where flavour changing neutral currents are suppressed by flavour symmetries.Comment: Typeset using REVTEX and EPSF, 5 pag, 2 figure

Impact of DM direct searches and the LHC analyses on branon phenomenology

Dark Matter direct detection experiments are able to exclude interesting parameter space regions of particle models which predict an important amount of thermal relics. We use recent data to constrain the branon model and to compute the region that is favored by CDMS measurements. Within this work, we also update present colliders constraints with new studies coming from the LHC. Despite the present low luminosity, it is remarkable that for heavy branons, CMS and ATLAS measurements are already more constraining than previous analyses performed with TEVATRON and LEP data.Comment: 17 pages, 2 figure

New Higgs signals induced by mirror fermion mixing effects

We study the conditions under which flavor violation arises in scalar-fermion interactions, as a result of the mixing phenomena between the standard model and exotic fermions. Phenomenological consequences are discussed within the specific context of a left-right model where these additional fermions have mirror properties under the new SU(2)_R gauge group. Bounds on the parameters of the model are obtained from LFV processes; these results are then used to study the LFV Higgs decays (H --> tau l_j, l_j = e, mu), which reach branching ratios that could be detected at future colliders.Comment: 12 pages, 2 figures, ReVTex4, graphicx, to be published in Phys. Rev.

Inference of the chromospheric magnetic field configuration of solar plage using the Ca II 8542 {\AA} line

It has so far proven impossible to reproduce all aspects of the solar plage chromosphere in quasi-realistic numerical models. The magnetic field configuration in the lower atmosphere is one of the few free parameters in such simulations. The literature only offers proxy-based estimates of the field strength, as it is difficult to obtain observational constraints in this region. Sufficiently sensitive spectro-polarimetric measurements require a high signal-to-noise ratio, spectral resolution, and cadence, which are at the limit of current capabilities. We use critically sampled spectro-polarimetric observations of the \cair line obtained with the CRISP instrument of the Swedish 1-m Solar Telescope to study the strength and inclination of the chromospheric magnetic field of a plage region. This will provide direct physics-based estimates of these values, which could aid modelers to put constraints on plage models. We increased the signal-to-noise ratio of the data by applying several methods including deep learning and PCA. We estimated the noise level to be $1\cdot10^{-3} I_c$. We then used STiC, a non-local thermodynamic equilibrium (NLTE) inversion code to infer the atmospheric structure and magnetic field pixel by pixel. We are able to infer the magnetic field strength and inclination for a plage region and for fibrils in the surrounding canopy. In the plage we report an absolute field strength of $|B| =440 \pm 90$ G, with an inclination of $10^\circ \pm 16^\circ$ with respect to the local vertical. This value for $|B|$ is roughly double of what was reported previously, while the inclination matches previous studies done in the photosphere. In the fibrillar region we found $|B| = 300 \pm 50$ G, with an inclination of $50^\circ \pm 13^\circ$.Comment: Accepted September 22t

UV photoprocessing of CO2 ice: a complete quantification of photochemistry and photon-induced desorption processes

Ice mantles that formed on top of dust grains are photoprocessed by the secondary ultraviolet (UV) field in cold and dense molecular clouds. UV photons induce photochemistry and desorption of ice molecules. Experimental simulations dedicated to ice analogs under astrophysically relevant conditions are needed to understand these processes. We present UV-irradiation experiments of a pure CO2 ice analog. Calibration of the QMS allowed us to quantify the photodesorption of molecules to the gas phase. This information was added to the data provided by the FTIR on the solid phase to obtain a complete quantitative study of the UV photoprocessing of an ice analog. Experimental simulations were performed in an ultra-high vacuum chamber. Ice samples were deposited onto an infrared transparent window at 8K and were subsequently irradiated with a microwave-discharged hydrogen flow lamp. After irradiation, ice samples were warmed up until complete sublimation was attained. Photolysis of CO2 molecules initiates a network of photon-induced chemical reactions leading to the formation of CO, CO3 ,O2 , and O3 . During irradiation, photon-induced desorption of CO and, to a lesser extent, O2 and CO2 took place through a process called indirect desorption induced by electronic transitions (DIET), with maximum photodesorption yields (Ypd) of 1.2 x 10-2 molecules/incident photon , 9.3 x 10-4 molecules/incident photon , and 1.1 x 10-4 molecules/incident photon , respectively. Calibration of mass spectrometers allows a direct quantification of photodesorption yields instead of the indirect values that were obtained from infrared spectra in most previous works. Supplementary information provided by infrared spectroscopy leads to a complete quantification, and therefore a better understanding, of the processes taking place in UV-irradiated ice mantles

Mass matrix Ansatz and lepton flavor violation in the THDM-III

Predictive Higgs-fermion couplings can be obtained when a specific texture for the fermion mass matrices is included in the general two-Higgs doublet model. We derive the form of these couplings in the charged lepton sector using a Hermitian mass matrix Ansatz with four-texture zeros. The presence of unconstrained phases in the vertices phi-li-lj modifies the pattern of flavor-violating Higgs interactions. Bounds on the model parameters are obtained from present limits on rare lepton flavor violating processes, which could be extended further by the search for the decay tau -> mu mu mu and mu-e conversion at future experiments. The signal from Higgs boson decays phi -> tau mu could be searched at the large hadron collider (LHC), while e-mu transitions could produce a detectable signal at a future e mu-collider, through the reaction e mu -> h0 -> tau tau.Comment: 17 pages, 9 figure

La precarización del Trabajo Social a través del voluntariado social: nuevos modos sociales de regulación en la relación capital-trabajo en el contexto puertorriqueño 2014-15

The precarization of social work through social volunteerism is scarcely studied in Puerto Rico. To explain how affects the volunteering like precarious factor in the profession, we used the theories of the French School of Regulation and the McDonaldization. These theories study the socio-institutional relations since its crystallization. As part of this crystallization it also explain the dynamics of State assuming public policies to shift their responsibilities to the private sphere. Social responsibilities become the subject of explicit international competition. Jessop (1993) calls this: “hollowed out” Shumpeterian workfare state. This type of state crystallized and systematized from public policies and the normalization of economic trends, such as laws governing incorporation. In order to understand this we use the speech analysis technique on Law number 261 of 2004 and the public debate to preapproval of it. In Puerto Rico this law, also known as the Volunteer Act of Puerto Rico, regulates social volunteering. In this process, social volunteering is established as a new working relationship simultaneously creating new bureaucratic institutions and private nonprofit organizations are created. New ways of working are justified through discourses of citizen participation and social responsibility. This has an effect of savings and profits for the capitalist classes, in this case resulting into economic and social losses for social workers.La precarización del trabajo social mediante el voluntariado social es un tema poco estudiado en Puerto Rico. Utilizamos teorías de la Escuela de la Regulación Francesa y la mcdonaldización de Ritzer (2007) para explicar cómo incide el voluntariado en la precarización de la profesión. Estas teorías estudian las relaciones socioinstitucionales desde su cristalización. Además, explican las dinámicas del Estado asumiendo políticas públicas para desplazar sus responsabilidades a la esfera privada. Jessop (1993) le llama a esto: Ahuecamiento shumpeteriano del Estado benefactor. Estas dinámicas se cristalizan y sistematizan a partir de políticas públicas y la normalización de las nuevas tendencias económicas. Observamos este proceso haciendo un análisis crítico del discurso (Van Dijk, 1999) de la Ley 261 del 2004 y del debate público de preaprobación de la misma. Esta Ley regula el voluntariado social en Puerto Rico y es conocida como Ley del Voluntariado de Puerto Rico. Observamos que el voluntariado social se instituye como nueva forma de trabajo y fomenta nuevas relaciones burocráticas entre instituciones y organizaciones privadas del tercer sector. Las nuevas formas de trabajo se justifican a través de discursos de participación ciudadana y responsabilidad social. Esto tiene un efecto de ahorros y ganancias para las clases capitalistas, tornándose en pérdidas económicas y sociales para los y las trabajadores/as sociales en este caso

Simultaneous Determination of Refractive Index and Thickness of Submicron Optical Polymer Films from Transmission Spectra

High-transparency polymers, called optical polymers (OPs), are used in many thin-film devices, for which the knowledge of film thickness (h) and refractive index (n) is generally required. Spectrophotometry is a cost-effective, simple and fast non-destructive method often used to determine these parameters simultaneously, but its application is limited to films where h > 500 nm. Here, a simple spectrophotometric method is reported to obtain simultaneously the n and h of a sub-micron OP film (down to values of a few tenths of a nm) from its transmission spectrum. The method is valid for any OP where the n dispersion curve follows a two-coefficient Cauchy function and complies with a certain equation involving n at two different wavelengths. Remarkably, such an equation is determined through the analysis of n data for a wide set of commercial OPs, and its general validity is demonstrated. Films of various OPs (pristine or doped with fluorescent compounds), typically used in applications such as thin-film organic lasers, are prepared, and n and h are simultaneously determined with the proposed procedure. The success of the method is confirmed with variable-angle spectroscopic ellipsometry.Spanish Ministry of Economy and Competitivity (MINECO) and European Community (FEDER) through grant no. MAT2015-66586-R