Detección de WIMPs con el detector TREX-DM

En este trabajo se aborda la cuestión de la materia oscura: evidencias y principales estrategias de búsqueda; y el detector TREX-DM en la búsqueda de WIMPs de baja masa: en qué consiste el experimento, como se recoge la señal y su situación actual.Se presenta el modelo de halo de materia oscura y se calculan los ritmos de interacción con distintos elementos para un WIMP sin espín de distintas masas.Además se realiza un análisis de sobre la uniformidad de la ganancia en uno de los dos detectores Micromegas que emplea TREX-DM con una calibración de cadmio 109 y esta información se utiliza para corregir espectros de energía.<br /

Análisis de una señal de WIMPs de baja masa en el experimento TREX-DM

En los experimentos de detección directa de materia oscura se buscan sucesos muy infrecuentes sepultados por un número de eventos de fondo mucho más numeroso. Esto obliga a desarrollar técnicas estadísticas que permitan cuantificar la presencia de un exceso de eventos achacables a la señal o en su defecto, establecer límites superiores. Se presentan aquí los fundamentos del contraste de hipótesis y varios métodos empleados con frecuencia en experimentos de materia oscura para establecer estos límites superiores, como el método del intervalo óptimo y el de máxima verosimilitud.Junto con este estudio de los fundamentos teóricos se realiza un recorrido por los principales experimentos de detección directa de materia oscura centrados en WIMPs de baja masa, con el objetivo de entender sus métodos de análisis y poder llevar a cabo un estudio similar con los primeros datos de TREX-DM, experimento instalado en el Laboratorio Subterráneo de Canfranc.Finalmente, se aplica un método de máxima verosimilitud para establecer límites superiores a una señal de WIMPs a partir de un espectro de fondo. De esta forma se elaboran dos curvas de sensibilidad para TREX-DM, con y sin umbral según el rango de energías seleccionado. Además, a partir de simulaciones de los fondos, se dan curvas de sensibilidad para los tres escenarios considerados en la propuesta original de TREX-DM, así como para el nivel de fondo más bajo alcanzado por un experimento de detección directa de materia oscura, Xenon1T, y su comparación con la curva proporcionada por el equipo de este experimento.<br /

Estudio de un detector con tecnología "Segmented-Mesh Microbulk" en física de sucesos raros

Este trabajo se centra en el estudio de un detector TPC con plano de lectura micromegas con mesh segmentada (segmented-mesh microbulk). Este tipo de detectores de nueva generación ofrecen una lectura bidimensional de las posiciones xy de los eventos, con resolución espacial mejorada respecto de los detectores micromegas con mesh no segmentada, lo que supone un avance en la capacidad de reconstrucción de la trayectoria de partículas cargadas dentro del volumen de gas. Entre las aplicaciones para las que se postulan, destacan las que se enmarcan dentro de la Búsqueda de Sucesos Raros, como la materia oscura o la desintegración doble beta sin neutrinos. El umbral energético es un aspecto clave para detectar eventos de bajaenergía como los inducidos por WIMPs de baja masa, candidatos a materia oscura. Por su parte, la desintegración doble beta sin neutrinos requiere de altas resoluciones energéticas que permitan la distinción de su señal del fondo.El objetivo principal de este trabajo es estudiar el impacto de las condiciones de medida sobre el umbral y resolución energéticos en función de la granularidad (tamaño de los canales de lectura) de un detector basado en el diseño de un prototipo existente, a través de simulaciones de Monte Carlo donde se han recreado las condiciones de medida experimentales<br /

Estudios de sensibilidad a SN utilizando un detector TPC esférico

El análisis de eventos astronómicos mediante diferentes mensajeros provenientes del medio interestelar es uno de los campos más desarrollados en el campo de la astrofísica, especialmente en el estudio de sucesos raros como las supernovas (SN). Uno de los grandes problemas es la posibilidad de que estos mensajeros pueden interactuar y alterarse a lo largo de su trayectoria. Por este motivo una de las últimas propuestas considera la detección de neutrinos como mensajeros ideales, en especial nos centraremos en el proceso de dispersión elástica coherente de neutrinos por un núcleo (CEvNS). Este canal de detección nos permitiría predecir y detectar eventos de supernovas mucho antes que cualquier otro experimento. Actualmente los detectores de neutrinos requieren de una gran extensión, lo cual limita en gran medida la cantidad de detectores disponibles y el control de los mismos. En este trabajo estudiaremos el diseño un detector gaseoso TPC con geometría esférica (STPC) y su viabilidad gracias a su bajo ruido electrónico y umbral de detección. Analizaremos las distintas características del detector, como el gas blanco a utilizar así como las diferentes configuraciones del mismo teniendo en cuenta su geometría, ubicación y la posible adición de un tanque de agua como sistema de reducción del fondo de detección. Para ello realizaremos análisis y simulaciones de las diferentes contribuciones al fondo de la señal de neutrinos donde obtendremos una señal de 6.38 eventos/keV/s con un fondo de 7 eventos/keV/s, concluyendo la posible viabilidad de la construcción del detector STPC en superficie con un tanque de agua usando mayores presiones o blindajes.<br /

Determinación algorítmica del grupo fundamental de un plano con agujeros y aplicaciones a la monodromía de trenzas

Se presentan conceptos de geometría algebraica como el grupo fundamental o las homotopías, de cara a su uso como base teórica para presentar las monodromías de trenzas obtenidas a partir de cubiertas. En particular este trabajo define el invariante algebraico de una curva conocido como monodromía de trenzas de la curva y se propone un método algorítmico para la obtención de bases geométricas del grupo fundamental del plano con agujeros, punto vital para la obtención de este invariante. Por supuesto, conceptos algebraicos necesarios como los grupos libres o los grupos de trenzas también se tratan aquí

Sexuality in people living with a serious mental illness: a meta‐synthesis of qualitative evidence

Introduction: Sexuality-related nursing care is scarce and mainly focuses on biological issues. There is also a lack of knowledge about how serious mental illnesses affect sexuality.Aim: To explain how people with a serious mental illness perceive and experience their sexuality. Method: A meta-synthesis was conducted to integrate qualitative studies. Four databases were used to perform the search, focused in the last ten years. Nine articles were included, and their results analysed thematically. Results: Four categories were identified: 'Pathologized sexuality', which explains how the disorder and treatment affect sexuality; 'Not my sexuality anymore", which describes feelings emerging from the perceived limitations and the role of selfacceptance; "Learning to manage intimate relationships", which explains the desire to establish intimate personal relationships and define their meaning; and 'Reconstructing my sexuality', which elucidates the influence of the environment on sexuality. Discussion: Sexuality is influenced by several factors, the main ones being: the clinical complications, the side effects of drug treatment, the social support, the relationship with the health sector, and stigma. Implications for Practice: Having a serious mental illness affects sexuality and can provoke suffering and social isolation. Mental health services should address this issue and carry out community interventions to reduce stigma. RELEVANCE STATEMENT: This study shows that having a serious mental illness affects sexuality and can provoke suffering and social isolation. Also, people living with a serious mental illness have not lost interest in maintaining an active sex life and, therefore, mental health services must respond to this need. Nurses can develop their role as health educators and should receive training on affective and sexual education to allow them to advise on options to develop the sexual dimension of these people. Additionally, mental health services should address this issue and carry out community interventions to reduce stigma

Sexuality in people living with a serious mental illness: A meta-synthesis of qualitative evidence

"Introduction: Sexuality-related nursing care is scarce and mainly focuses on biological issues. There is also a lack of knowledge about how serious mental illnesses affect sexuality. Aim: To explain how people with a serious mental illness perceive and experience their sexuality Method: A meta-synthesis was conducted to integrate qualitative studies. Four databases were used to perform the search, focused in the last ten years. Nine articles were included, and their results analysed thematically. Results: Four categories were identified: ""Pathologized sexuality,"" which explains how the disorder and treatment affect sexuality; ""Not my sexuality anymore,” which describes feelings emerging from the perceived limitations and the role of self-acceptance; “Learning to manage intimate relationships,” which explains the desire to establish intimate personal relationships and define their meaning; and ""Reconstructing my sexuality,"" which elucidates the influence of the environment on sexuality. Discussion: Sexuality is influenced by several factors, the main ones being: the clinical complications, the side effects of drug treatment, the social support, the relationship with the health sector and stigma. Implications for practice: Having a serious mental illness affects sexuality and can provoke suffering and social isolation. Mental health services should address this issue and carry out community interventions to reduce stigma.

Searching for WIMPs with TREX-DM: achievements and challenges

The TREX-DM detector, a low background chamber with microbulk Micromegas readout, was commissioned in the underground laboratory of Canfranc (LSC) in 2018. Since then, data taking campaigns have been carried out with Argon and Neon mixtures, at different pressures from 1 to 4 bar. By achieving a low energy threshold of 1 keV$_{ee}$ and a background level of 80 counts keV$^{-1}$ Kg$^{-1}$ day$^{-1}$ in the region from 1 to 7 keV$_{ee}$, the experiment demonstrates its potential to search for low-mass WIMPs. Two of the most important challenges currently faced are the reduction of both, background level and energy threshold. With respect to the energy threshold, recently a new readout plane is being developed, based on the combination of Micromegas and GEM technologies, aiming to have a pre-amplification stage that would permit very low energy thresholds, close to the single-electron ionization energy. With respect to the background reduction, apart from studies to identify and minimize contamination population, a high sensitivity alpha detector is being developed in order to allow a proper material selection for the TREX-DM detector components. Both challenges, together with the optimization of the gas mixture used as target for the WIMP detection, will take TREX-DM to explore regions of WIMP's mass below 1 GeV c$^{-2}$.Comment: LIDINE 2023: LIght Detection In Noble Element

Meta-Analysis and Validation of a Colorectal Cancer Risk Prediction Model Using Deep Sequenced Fecal Metagenomes

Simple Summary Colorectal cancer (CRC) is the third most common cancer in the world. The gut microbiome, which includes a collection of microbes, is a potential modifiable risk factor. The study of the microbiome is complex and many issues remain unsolved despite the scientific efforts that have been recently made. The present study aimed to build a CRC predictive model performing a meta-analyses of previously published shotgun metagenomics data, and to validate it in a new study. For that purpose, 156 participants of a CRC screening program were recruited, with an even distribution of CRCs, high-risk colonic precancerous lesions, and a control group with normal colonic mucosa. We have identified a signature of 32 bacterial species that have a good predictive accuracy to identify CRC but not precancerous lesions. This suggests that the identified microbes that were enriched or depleted in CRC are merely a consequence of the tumor. The gut microbiome is a potential modifiable risk factor for colorectal cancer (CRC). We re-analyzed all eight previously published stool sequencing data and conducted an MWAS meta-analysis. We used cross-validated LASSO predictive models to identify a microbiome signature for predicting the risk of CRC and precancerous lesions. These models were validated in a new study, Colorectal Cancer Screening (COLSCREEN), including 156 participants that were recruited in a CRC screening context. The MWAS meta-analysis identified 95 bacterial species that were statistically significantly associated with CRC (FDR < 0.05). The LASSO CRC predictive model obtained an area under the receiver operating characteristic curve (aROC) of 0.81 (95%CI: 0.78-0.83) and the validation in the COLSCREEN dataset was 0.75 (95%CI: 0.66-0.84). This model selected a total of 32 species. The aROC of this CRC-trained model to predict precancerous lesions was 0.52 (95%CI: 0.41-0.63). We have identified a signature of 32 bacterial species that have a good predictive accuracy to identify CRC but not precancerous lesions, suggesting that the identified microbes that were enriched or depleted in CRC are merely a consequence of the tumor. Further studies should focus on CRC as well as precancerous lesions with the intent to implement a microbiome signature in CRC screening programs

Search for supersymmetry in final states with two same-sign or three leptons and jets using 36 fb⁻¹ of √s=13 TeV pp collision data with the ATLAS detector

A search for strongly produced supersymmetric particles using signatures involving multiple energetic jets and either two isolated same-sign leptons (e or μ), or at least three isolated leptons, is presented. The analysis relies on the identification of b-jets and high missing transverse momentum to achieve good sensitivity. A data sample of proton-proton collisions at s=13 TeV recorded with the ATLAS detector at the Large Hadron Collider in 2015 and 2016, corresponding to a total integrated luminosity of 36.1 fb −1 , is used for the search. No significant excess over the Standard Model prediction is observed. The results are interpreted in several simplified supersymmetric models featuring R-parity conservation or R-parity violation, extending the exclusion limits from previous searches. In models considering gluino pair production, gluino masses are excluded up to 1.87 TeV at 95% confidence level. When bottom squarks are pair-produced and decay to a chargino and a top quark, models with bottom squark masses below 700 GeV and light neutralinos are excluded at 95% confidence level. In addition, model-independent limits are set on a possible contribution of new phenomena to the signal region yields.[Figure not available: see fulltext.]