Supersymmetry searches in ATLAS at the LHC

La Física de Partículas es la rama de la ciencia que estudia los componentes elementales del Universo y sus interacciones fundamentales. La teoría de las partículas fundamentales y sus interacciones es conocida como el Modelo Estándar (SM). Éste proporciona la descripción más precisa, hasta la fecha, de la fenomenología de la Física de Partículas Elementales. Su validez ha sido demostrada hasta escalas de energía del orden de TeV. No obstante, el SM no se considera la teoría fundamental definitiva ya que existe evidencia de Nueva Física imposible de describir con el SM como la existencia de Materia Oscura, la asimetría entre materia y antimateria del Universo, las masas de los neutrinos o el problema de la jerarquía. Por lo tanto, el SM necesita, o bien una extensión, o bien ser incluido en una teoría más completa. Varias hipótesis se han desarrollado en esta dirección, entre las que destaca la Supersimetría (SUSY). Se ha demostrado que SUSY es la única extensión posible de las simetrías espacio-temporales conocidas en las interacciones de partículas y que podría, si existe, resolver muchos de los problemas del SM. La característica clave de la fenomenología de SUSY es la predicción de “spartículas” (partículas supersimétricas). Cada partícula del SM tiene una compañera supersimétrica de la que difiere en spin en 1/2. De momento, ningún experimento ha observado estas supercompañeras, lo cual indica que SUSY tendría que ser una simetría rota, por lo que las spartículas deberían ser más masivas que sus compañeras del SM. Puesto que se sabe muy poco sobre el mecanismo de ruptura y del espectro de masa de las nuevas partículas, las posibles señales de SUSY pueden ser muy diversas dependiendo del modelo particular que se considere. Para producir partículas muy pesadas (como las que predice SUSY) se necesitan colisiones a altísimas energías. Para ello se utilizan aceleradores que pueden incrementar la energía de dos haces de partículas y hacerlos colisionar. El Gran Colisionador Hadrónico (LHC), operado por el Laboratorio Europeo de Física de Partículas (CERN), es uno de estos aceleradores en el que se producen colisiones entre protones. Con su energía en el centro de masas y su luminosidad sin precedentes, ofrece unas condiciones excelentes para la búsqueda de nuevas partículas con masas del orden de TeV. Varios detectores de grandísimas dimensiones observan y registran los resultados de estas colisiones. Entre ellos se encuentra ATLAS, uno de los cuatro detectores de más envergadura del LHC. Esta Tesis presenta dos búsquedas distintas de Supersimetría utilizando datos de ATLAS. La primera consiste en una búsqueda de Supersimetría, con violación bilineal de paridad R (bRPV), utilizando 4,7/fb de datos a una energía en el centro de masas de 7 TeV. La característica más relevante de los modelos de bRPV SUSY es que la partícula supersimétrica más ligera (LSP) es inestable y se desintegra en partículas del SM en vez de escapar sin ser vista como predicen los modelos de conservación de paridad R. Este análisis consiste en la selección de estados finales con un leptón (electrón o muon), siete o más jets y energía transversa faltante (EtMiss). En este contexto se define una región de señal (SR) en la que se predice que bRPV domina sobre el fondo de SM. Para asegurar que el comportamiento de los fondos del SM se entienden correctamente se definen también un conjunto de regiones de control y validación ortogonales a la SR. Los principales procesos de fondo en la SR son la producción de quarks top y la producción de bosones W y Z junto con jets. Además, también es importante la estimación de la producción de jets de QCD. La estimación del fondo en la SR es 4,3 ± 1,2 (2,2 ± 1,1) sucesos en el canal del electrón (muon) y el número de sucesos observados en los datos es 7 (7). Esto supone una discrepancia entre datos y predicción de 1,1 (2,1) desviaciones estándar. Por lo tanto se puede concluir que no hay discrepancias significativas entre el número esperado de sucesos del SM y los datos observados. Éste acuerdo entre datos y SM se interpreta en términos del modelo bRPV-mSUGRA, estableciendo límites de exclusión en sus parámetros. El otro escenario que presenta esta Tesis es una búsqueda de Supersimetría con estados finales que contienen un bosón Z que se desintegra leptónicamente, jets y gran cantidad de EtMiss. Los datos de colisiones protón-protón que se han utilizado en esta búsqueda se recopilaron durante 2012 a una energía en el centro de masas de 8 TeV y corresponden a una luminosidad integrada de 20,3/fb. Los fondos dominantes provienen de los llamados procesos simétricos en sabor y de dibosones con producción real de bosones Z. Los resultados de la estimación total de los fondos son: 4,2 ± 1,6; 6,4 ± 2,2 y 10,6 ± 3,2 para los canales electrón-electrón, muon-muon y la suma de ambos, respectivamente. El total de sucesos observados en los datos en estos canales es 16, 13 y 29, lo cual indica que los datos exceden las predicciones con una significancia de 3, 1,7 y 3 desviaciones estándar respectivamente. El número predicho de sucesos del SM y el observado están en perfecto acuerdo en todas las regiones de control y de validación, con lo que este exceso puede interpretarse como un indicio de Nueva Física o como una fluctuación estadística, necesitándose los datos del Run 2 del LHC para discernir entre ambas posibilidades. Estos resultados se han interpretado en un modelo de Suersymetría GGM donde el gravitino es la LSP y un neutralino de tipo higgsino es la segunda partícula supersimétrica más ligera. Los límites de exclusión observados para estos modelos son menos restrictivos que los predichos debido al exceso de sucesos en los datos

The global NAFLD policy review and preparedness index: Are countries ready to address this silent public health challenge?

Background & Aims: Non-alcoholic fatty liver disease (NAFLD) is a highly prevalent, yet largely underappreciated liver condition which is closely associated with obesity and metabolic disease. Despite affecting an estimated 1 in 4 adults globally, NAFLD is largely absent on national and global health agendas. Methods: We collected data from 102 countries, accounting for 86% of the world population, on NAFLD policies, guidelines, civil society engagement, clinical management, and epidemiologic data. A preparedness index was developed by coding questions into 6 domains (policies, guidelines, civil awareness, epidemi ology and data, NAFLD detection, and NAFLD care management) and categorising the responses as high, medium, and low; a multiple correspondence analysis was then applied. Results: The highest scoring countries were India (42.7) and the United Kingdom (40.0), with 32 countries (31%) scoring zero out of 100. For 5 of the domains a minority of countries were cat egorised as high-level while the majority were categorised as low-level. No country had a national or sub-national strategy for NAFLD and <2% of the different strategies for related conditions included any mention of NAFLD. National NAFLD clinical guide lines were present in only 32 countries. Conclusions: Although NAFLD is a pressing public health prob lem, no country was found to be well prepared to address it. There is a pressing need for strategies to address NAFLD at na tional and global levels. Lay summary: Around a third of the countries scored a zero on the NAFLD policy preparedness index, with no country scoring over 50/100. Although NAFLD is a pressing public health prob lem, a comprehensive public health response is lacking in all 102 countries. Policies and strategies to address NAFLD at the na tional and global levels are urgently needed

MADNESS: A Multiresolution, Adaptive Numerical Environment for Scientific Simulation

MADNESS (multiresolution adaptive numerical environment for scientific simulation) is a high-level software environment for solving integral and differential equations in many dimensions that uses adaptive and fast harmonic analysis methods with guaranteed precision based on multiresolution analysis and separated representations. Underpinning the numerical capabilities is a powerful petascale parallel programming environment that aims to increase both programmer productivity and code scalability. This paper describes the features and capabilities of MADNESS and briefly discusses some current applications in chemistry and several areas of physics

Non-parametric deprojection of NIKA SZ observations: Pressure distribution in the Planck-discovered cluster PSZ1 G045.85+57.71

The determination of the thermodynamic properties of clusters of galaxies at intermediate and high redshift can bring new insights into the formation of large-scale structures. It is essential for a robust calibration of the mass-observable scaling relations and their scatter, which are key ingredients for precise cosmology using cluster statistics. Here we illustrate an application of high resolution $(< 20$ arcsec) thermal Sunyaev-Zel'dovich (tSZ) observations by probing the intracluster medium (ICM) of the \planck-discovered galaxy cluster \psz\ at redshift $z = 0.61$, using tSZ data obtained with the NIKA camera, which is a dual-band (150 and 260~GHz) instrument operated at the IRAM 30-meter telescope. We deproject jointly NIKA and \planck\ data to extract the electronic pressure distribution from the cluster core ($R \sim 0.02\, R_{500}$) to its outskirts ($R \sim 3\, R_{500}$) non-parametrically for the first time at intermediate redshift. The constraints on the resulting pressure profile allow us to reduce the relative uncertainty on the integrated Compton parameter by a factor of two compared to the \planck\ value. Combining the tSZ data and the deprojected electronic density profile from \xmm\ allows us to undertake a hydrostatic mass analysis, for which we study the impact of a spherical model assumption on the total mass estimate. We also investigate the radial temperature and entropy distributions. These data indicate that \psz\ is a massive ($M_{500} \sim 5.5 \times 10^{14}$ M$_{\odot}$) cool-core cluster. This work is part of a pilot study aiming at optimizing the treatment of the NIKA2 tSZ large program dedicated to the follow-up of SZ-discovered clusters at intermediate and high redshifts. (abridged)Comment: 16 pages, 10 figure

NIKA2: a mm camera for cluster cosmology

Galaxy clusters constitute a major cosmological probe. However, Planck 2015 results have shown a weak tension between CMB-derived and cluster-derived cosmological parameters. This tension might be due to poor knowledge of the cluster mass and observable relationship. As for now, arcmin resolution Sunyaev-Zeldovich (SZ) observations ({\it e.g.} SPT, ACT and Planck) only allowed detailed studies of the intra cluster medium for low redshift clusters ($z0.5$) high resolution and high sensitivity SZ observations are needed. With both a wide field of view (6.5 arcmin) and a high angular resolution (17.7 and 11.2 arcsec at 150 and 260 GHz), the NIKA2 camera installed at the IRAM 30-m telescope (Pico Veleta, Spain) is particularly well adapted for these observations. The NIKA2 SZ observation program will map a large sample of clusters (50) at redshifts between 0.5 and 0.9. As a pilot study for NIKA2, several clusters of galaxies have been observed with the pathfinder, NIKA, at the IRAM 30-m telescope to cover the various configurations and observation conditions expected for NIKA2.

Nika2: A mm camera for cluster cosmology

Galaxy clusters constitute a major cosmological probe. However, Planck 2015 results have shown a weak tension between CMB-derived and cluster-derived cosmological parameters. This tension might be due to poor knowledge of the cluster mass and observable relationship. As for now, arcmin resolution Sunyaev-Zeldovich (SZ) observations (e.g. SPT, ACT and Planck) only allowed detailed studies of the intra cluster medium for low redshift clusters (z 0:5) high resolution and high sensitivity SZ observations are needed. With both a wide field of view (6.5 arcmin) and a high angular resolution (17.7 and 11.2 arcsec at 150 and 260 GHz), the NIKA2 camera installed at the IRAM 30-m telescope (Pico Veleta, Spain) is particularly well adapted for these observations. The NIKA2 SZ observation program will map a large sample of clusters (50) at redshifts between 0.5 and 0.9. As a pilot study for NIKA2, several clusters of galaxies have been observed with the pathfinder, NIKA, at the IRAM 30-m telescope to cover the various configurations and observation conditions expected for NIKA2

A scoping review of the changing landscape of geriatric medicine in undergraduate medical education: curricula, topics and teaching methods

Purpose The world’s population is ageing. Therefore, every doctor should receive geriatric medicine training during their undergraduate education. This review aims to summarise recent developments in geriatric medicine that will potentially inform developments and updating of undergraduate medical curricula for geriatric content. Methods We systematically searched the electronic databases Ovid Medline, Ovid Embase and Pubmed, from 1st January 2009 to 18th May 2021. We included studies related to (1) undergraduate medical students and (2) geriatric medicine or ageing or older adults and (3) curriculum or curriculum topics or learning objectives or competencies or teaching methods or students’ attitudes and (4) published in a scientific journal. No language restrictions were applied. Results We identified 2503 records and assessed the full texts of 393 records for eligibility with 367 records included in the thematic analysis. Six major themes emerged: curriculum, topics, teaching methods, teaching settings, medical students’ skills and medical students’ attitudes. New curricula focussed on minimum Geriatrics Competencies, Geriatric Psychiatry and Comprehensive Geriatric Assessment; vertical integration of Geriatric Medicine into the curriculum has been advocated. Emerging or evolving topics included delirium, pharmacotherapeutics, healthy ageing and health promotion, and Telemedicine. Teaching methods emphasised interprofessional education, senior mentor programmes and intergenerational contact, student journaling and reflective writing, simulation, clinical placements and e-learning. Nursing homes featured among new teaching settings. Communication skills, empathy and professionalism were highlighted as essential skills for interacting with older adults. Conclusion We recommend that future undergraduate medical curricula in Geriatric Medicine should take into account recent developments described in this paper. In addition to including newly emerged topics and advances in existing topics, different teaching settings and methods should also be considered. Employing vertical integration throughout the undergraduate course can usefully supplement learning achieved in a dedicated Geriatric Medicine undergraduate course. Interprofessional education can improve understanding of the roles of other professionals and improve team-working skills. A focus on improving communication skills and empathy should particularly enable better interaction with older patients. Embedding expected levels of Geriatric competencies should ensure that medical students have acquired the skills necessary to effectively treat older patients

Mapping the kinetic Sunyaev-Zel'dovich effect toward MACS J0717.5+3745 with NIKA

Measurement of the gas velocity distribution in galaxy clusters provides insight into the physics of mergers, through which large scale structures form in the Universe. Velocity estimates within the intracluster medium (ICM) can be obtained via the Sunyaev-Zel'dovich (SZ) effect, but its observation is challenging both in term of sensitivity requirement and control of systematic effects, including the removal of contaminants. In this paper we report resolved observations, at 150 and 260 GHz, of the SZ effect toward the triple merger MACS J0717.5+3745 (z=0.55), using data obtained with the NIKA camera at the IRAM 30m telescope. Assuming that the SZ signal is the sum of a thermal (tSZ) and a kinetic (kSZ) component and by combining the two NIKA bands, we extract for the first time a resolved map of the kSZ signal in a cluster. The kSZ signal is dominated by a dipolar structure that peaks at -5.1 and +3.4 sigma, corresponding to two subclusters moving respectively away and toward us and coincident with the cold dense X-ray core and a hot region undergoing a major merging event. We model the gas electron density and line-of-sight velocity of MACS J0717.5+3745 as four subclusters. Combining NIKA data with X-ray observations from XMM-Newton and Chandra, we fit this model to constrain the gas line-of-sight velocity of each component, and we also derive, for the first time, a velocity map from kSZ data (i.e. that is model-dependent). Our results are consistent with previous constraints on the merger velocities, and thanks to the high angular resolution of our data, we are able to resolve the structure of the gas velocity. Finally, we investigate possible contamination and systematic effects with a special care given to radio and submillimeter galaxies. Among the sources that we detect with NIKA, we find one which is likely to be a high redshift lensed submillimeter galaxy.Comment: 19 pages, 9 figures, accepted in A&

The NIKA2 large-field-of-view millimetre continuum camera for the 30 m IRAM telescope

Context. Millimetre-wave continuum astronomy is today an indispensable tool for both general astrophysics studies (e.g. star formation, nearby galaxies) and cosmology (e.g. cosmic microwave background and high-redshift galaxies). General purpose, large-field-of-view instruments are needed to map the sky at intermediate angular scales not accessible by the high-resolution interferometers (e.g. ALMA in Chile, NOEMA in the French Alps) and by the coarse angular resolution space-borne or ground-based surveys (e.g. Planck, ACT, SPT). These instruments have to be installed at the focal plane of the largest single-dish telescopes, which are placed at high altitude on selected dry observing sites. In this context, we have constructed and deployed a three-thousand-pixel dual-band (150 GHz and 260 GHz, respectively 2 mm and 1.15 mm wavelengths) camera to image an instantaneous circular field-of-view of 6.5 arcmin in diameter, and configurable to map the linear polarisation at 260 GHz. Aims. First, we are providing a detailed description of this instrument, named NIKA2 (New IRAM KID Arrays 2), in particular focussing on the cryogenics, optics, focal plane arrays based on Kinetic Inductance Detectors, and the readout electronics. The focal planes and part of the optics are cooled down to the nominal 150 mK operating temperature by means of an adhoc dilution refrigerator. Secondly, we are presenting the performance measured on the sky during the commissioning runs that took place between October 2015 and April 2017 at the 30-m IRAM telescope at Pico Veleta, near Granada (Spain). Methods. We have targeted a number of astronomical sources. Starting from beam-maps on primary and secondary calibrators we have then gone to extended sources and faint objects. Both internal (electronic) and on-the-sky calibrations are applied. The general methods are described in the present paper. Results. NIKA2 has been successfully deployed and commissioned, performing in-line with expectations. In particular, NIKA2 exhibits full width at half maximum angular resolutions of around 11 and 17.5 arcsec at respectively 260 and 150 GHz. The noise equivalent flux densities are, at these two respective frequencies, 33±2 and 8±1 mJy s1/2. A first successful science verification run was achieved in April 2017. The instrument is currently offered to the astronomy community and will remain available for at least the following ten years