Master Theses 2019/20

Master Theses proposed by CIEMAT-CFP Members for the academic year 2019/2020

 

Scintillation light analysis with the ProtoDUNE (Deep Underground Neutrino Experiment) detector at CERN

Future neutrino experiments like DUNE in Fermilab (USA), whose main goal is to measure the CP symmetry violation in the leptonic sector, will consist of liquid argon TPC detectors exposed to neutrino beams. In this context, ProtoDUNE is a 300 ton prototype that has just started to take data at CERN. The neutrino group at CIEMAT is responsible for the scintillation light detection system of this detector, which comprises a set of large photomultipliers operating at cryogenic temperature. The tasks proposed in this End-of-Master project include the data analysis and the simulation of the processes that take place in the detector to characterize the production, propagation and detection of the scintillation signal. 


Contact: Dr. Carmen Palomares (CIEMAT) (mc.palomares@ciemat.es), Dr. Clara Cuesta (CIEMAT) (clara.cuesta@ciemat.es)

Supernova neutrino detection in the liquid argon DUNE experiment

The Deep Underground Neutrino Experiment (DUNE) will pursue a broad program on neutrino physics and astrophysics with a 40 kt liquid argon detector at the Sanford Underground Research Facility (SURF) 1300 km from Fermilab (USA). The size and underground location of the DUNE far detector will allow undertaking not only neutrino oscillations studies leading to measuring the CP violating phase, but also searches for new phenomena and the detection of astrophysical processes involving neutrino emission.

This End-of-Master project will be focused on studying the core-collapse supernova neutrino production, neutrino oscillation effects and their detection in underground experiments. In particular, the DUNE sensitivity to the electron flavor component will be evaluated and the potential information about the neutrino mass ordering and the dynamics and neutronization of a star's central core will be studied.

 

Contact: Dr. Inés GIl Botella (CIEMAT) (ines.gil@ciemat.es)

A study on the measurement of the SM Higgs boson in the semileptonic WW channel at the CMS experiment of the LHC collider (CERN)

The discovery of the standard model (SM) Higgs boson, with a mass close to 125 GeV, by the CERN LHC experiments ATLAS and CMS in 2012 represents a major breakthrough in particle physics.

This new particle has been observed and studied in a number of final states including the WW fully leptonic decay.

For the semiletonic WW final state, large SM backgrounds from W+Jets and top quark processes make a measurement of the Higgs boson much more difficult. One practical solution may be to use machine learning techniques to differentiate between the large SM backgrounds and the Higgs boson signal. This approach would require the optimisation of the Higgs boson candidate reconstruction and the identification of multiple discriminating variables.

It is proposed to perform a simulation level study on the plausibility of a measurement of the SM Higgs boson in the semileptonic WW channel at the CMS experiment.

Contact: Dr. Dermot Moran (Dermot.Moran@ciemat.es)

Analysis of the data of Dark Matter ArDM/DART and DEAP-3600 Dark Matter experiments

The nature of Dark Matter is widely considered as one of the most important open questions of modern physics. Multiple observations suggest that less than 15% of the universe's matter content is made of ordinary matter, while the largest contribution is given by non-luminous and non-baryonic matter that manifests itself only through its gravitational effects. A possible explanation for the Dark Matter problem lies in the existence of weakly interacting massive particles called WIMPs, remnants of the Big Bang. There are several global projects underway, carried out in underground laboratories, looking for tiny signals produced by WIMP interactions. One of them is the DEAP-3600 experiment, with 3600 kg of liquid argon, which is located in the SNOLAB laboratory (Canada). The CIEMAT-DM group participates in data collection and analysis, developing advanced analysis techniques in order to optimize the sensitivity of the WIMPs signal, significantly reducing the background events. On the other hand, our group participates in the ArDM/DART experiment, installed in the Canfranc Underground Laboratory under the Pyrenees, which aims to measure radionuclide contamination in argon radiopure, which is one of the most important parameters to define the sensitivity to WIMPs detection.
The purpose of this master's work is to contribute to the analysis of the data currently being taken by the DEAP-3600 and ArDM/DART experiments, to verify the performance of liquid argon detectors and their capability to reject background events. The proposed tasks involve an intense learning of particle physics, nuclear and detectors, providing an excellent experience to face a thesis in particle physics or astrophysics

 

Contact: Dr. Pablo Garcia (CIEMAT), Dr. Vicente Pesudo (CIEMAT) - (DarkMatter@ciemat.es)

Study, construction and development of a new dual-phase argon detector for direct search of Dark Matter with the DarkSide-20k experiment

The direct detection of dark matter is one of the main challenges in modern physics and its discovery would mean an tremendous advance in knowledge both in the fundamental ingredients of the universe and in the role they played in its early evolution. The CIEMAT's Dark Matter group (CIEMAT-DM) has a long time experience in this field, particularly in the design, construction, operation and data analysis of experiments based on liquid argon detectors. We are currently participating in the ArDM (LSC, Canfranc, Spain) and DEAP-3600 (SNOLAB, Canada) experiments. In order to overcome the current experimental limits on the detection of weakly interacting massive particles called (WIMPs), it is required a new generation of very massive detectors. DarkSide-20k will be the largest liquid argon detector  for direct detection of dark matter. With 20 tons of active material in the fiducial volume, it will have an unprecedented sensitivity to WIMP signals. This detector will be installed underground at the Gran Sasso National Laboratory (Italy) and will start taking data in 2022. For this investigation,  the purity of the materials from the point of view of natural radioactivity and the ability to discriminate signal and background are fundamental aspects. The objectives of the work can be adapted to the interests of the student, focusing on the material radio-purity analysis  and/or on Monte Carlo simulations necessary for the calculation of the background of the experiment. All the proposed tasks involve an intense learning of particle physics, nuclear and detectors, providing an excellent experience to face a thesis in particle physics or astrophysics

Contact: Dr. Luciano Romero (CIEMAT), Dr. Roberto Santorelli (CIEMAT) - (DarkMatter@ciemat.es)

Development of new algorithms based on machine learning for the classification of the events in the DEAP-3600 and DarkSide experiments

Artificial intelligence and especially neural networks are being widely used in particle physics to extract information from large volumes of data. On the other hand, one of the most relevant challenges of today's physics is the understanding of the nature of Dark Matter. One of the most promising candidates is the weakly interactive massive particles (WIMP), which are attempted to be detected by means of experiments based on liquid argon such as DEAP-3600 and DarkSide. The large amount of data generated by these experiments has to be processed and analyzed  quickly and in a reliable way, for this reason, algorithms based on machine learning can play a relevant role. DEAP-3600  is a 3.6 ton liquid argon detector currently taking dark matter data in the SNOLAB laboratory (Canada). The main objective of this work is the classification, with neural networks, of different types of events in the DEAP-3600 experiment,  rejecting the background and identifying the potential dark matter signal.

 

Contact: Dr. Miguel Cárdenas (CIEMAT), Dr. Vicente Pesudo (CIEMAT) - (DarkMatter@ciemat.es)

First optical observations with sub-milliarcsecond angular resolution using the MAGIC telescopes

Imaging Atmospheric Cherenkov telescopes, such as the two MAGIC telescopes at Roque de los Muchachos observatory, observe the sky in the very high energy gamma ray range. On top of that, thanks to their 17 meter diameter mirrors and ultrafast photodetectors (ns), they are ideal for intensity interferometry observations in the optical range. This technique allows to turn them into these instruments with the telescopes with the highest angular resolution in the visible range. They can reach a resolution of hundreds of microarcseconds, allowing them to study the size and shape of stars, accretion or decretion disks, star spots and stellar winds. We have successfully completed the first star detections with MAGIC and we plan to take new data in the 2019/2020 season. This master’s thesis focuses on the identification of optimal candidates for the new observations and the analysis and scientific interpretation of the data.


Contact: Dr. Juan Cortina (CIEMAT) (Juan.Cortina@ciemat.es) y Dr. Tarek Hassan (DESY Zeuthen, Alemania)

Interpretation of the signal in the positron spectrum of cosmic rays observed by AMS

The latest results of the AMS-02 magnetic spectrometer, operating on the International Space Station since 2011, provide a precise description of the excess observed in the cosmic-ray positron flux. This measurement requires the introduction of an additional source not included in the state-of-the-art models. The source is either an

astrophysical object or the result of the annihilation of Dark Matter particles in the halo of our Galaxy.

Other explanations have been recently proposed. The goal of this TFM is to investigate the consistency of the alternative descriptions of the AMS-02 signal.

 

Contact: Dr. Carlos Mañá (Carlos.Mana@ciemat.es) , Dr. Jorge Casaus (Jorge.Casaus@ciemat.es)

Fundamental Physics Research with Future Space-borne Cosmic Ray Detectors

The precise measurements of cosmic rays provide one the most sensitive methods for fundamental physics research. Space-borne experiments, that provide a direct measurement of the cosmic ray properties, have precisely measured the distortions in their energy spectra and composition.

This could indicate the presence of physics beyond the Standard Model. The next generation of experiments, with improved sensitivities, will disentangle the origin of the observed phenomena. The goal of this TFM is to compare the capabilities of the future space-borne cosmic ray detectors

Contact: Dr. Javier Berdugo (Javier.Berdugo@ciemat.es) , Dr. Jorge Casaus (Jorge.Casaus@ciemat.es)

Precise Measurement of the Velocity of Charged Particles in Space-Borne Experiments

The determination of the mass of the subatomic particles that constitute the cosmic rays requires a precise measurement of their velocity. Among the different experimental techniques in use at space-borne experiments, the measurement of the Cerenkov radiation as well the Time-of-Flight provide the best performances. The Ring Imaging Cerenkov detector (RICH) in the magnetic spectrometer AMS-02, in operation on the International Space Station since 2011, provides velocity measurements with a resolution better than one per mil. The new generation of space-borne magnetic spectrometers will require comparable precisions, but making use of the Time-of-Flight technique. The goal of this TFM is to study the performance of the AMS-02 RICH during its 10-year operation in space and to validate, using measurements performed in our lab, the expected performance of the instruments proposed for precise velocity measurements in the future space-borne cosmic ray detectors.

Contact: Dr. Jorge Casaus (Jorge.Casaus@ciemat.es) , Dr. Carlos Mañá (Carlos.Mana@ciemat.es)

Relación de colores de las galaxias con su tasa de formación estelar

Las galaxias  suelen caer en una secuencia continua con una cierta dispersión en los diagramas color-color. Según los modelos PoPStar los objetos que tienen formación estelar (SFR) más intensa, tendrán una contaminación en los colores en banda ancha debido a líneas de emisión. La contribución de éstas, debidas a las poblaciones estelares mas jóvenes, hacen que los colores se muevan de manera transversal a la banda de la secuencia principal de galaxias en esos diagramas color-color, siendo la distancia a esa banda una medida de la intensidad de la formación estelar y/o de la edad de ese último brote reciente de formación de estrellas. Dado que la formación estelar ha sido mayor en el pasado, este efecto debería ser más claro a alto redshift.

El objetivo del trabajo es hacer un análisis de los datos del Dark Energy Survey (DES) en 4 bandas para galaxias, hacer grupos de galaxias con menor y mayor SFR y comprobar si los "outliers" aparecen en mayor medida a mayores redshifts. El trabajo implica:

 

1) Aprender a manejar un catálogo masivo de más de 200 millones de galaxias de DES

2) seleccionar los objetos relevantes y usar herramientas estadísticas para determinar si hay alguna correlación que nos permita comprobar si el resultado predicho es observable.

3) Asimismo, se podrían utilizar datos del survey espectrofotométrico PAU para comprobar la presencia de las líneas para estos outliers en las áreas comunes con DES.

 

Directores: Ignacio Sevilla (Ignacio.Sevilla@ciemat.es) y Mercedes Mollá (Mercedes.Molla@ciemat.es)

Composición química en las estrellas de la librería de MEGARA y búsqueda de elementos raros

El trabajo consiste en el análisis espectral de las estrellas observadas en la librería de MEGARA-GTC para la identificación y medida de líneas espectrales. El trabajo incluye las siguientes tareas

  1. Búsqueda de librerías de líneas espectrales a la resolución de MEGARA en los setups de HR-R y HR-I
  2. Creación de un software que permita la identificación automática de las líneas incluyendo una figura de mérito que describa la probabilidad de la correcta identificación en cada caso
  3. Búsqueda sistemática de líneas “raras” en la librería de estrellas de MEGARA (número de espectros disponibles: 20)
  4. Medidas de las intensidades de las líneas y sus anchuras equivalentes

 

Directores: Mercedes Mollá (Mercedes.Molla@ciemat.es) y Marisa García –Varga (Fractal SLNE)

 

Análisis de poblaciones estelares en galaxias a redshift 0.5 < z < 1.0

Este trabajo implica el análisis de espectros de galaxias anfitrionas de supernovas tipo Ia a alto redshift en los catálogos de VVDS, DEEP2, y COSMOS.

El objetivo del trabajo caracterizar estas galaxias usando el programa FADO, que da como resultados las mejores combinaciones de poblaciones estelares capaces de reproducir los datos, y obtener así la historia de formación estelar (SF) y la evolución de la metalicidad estelar Z* de cada galaxia. El proyecto implica aprendizaje de manejo y uso de la herramienta FADO, aprender que es la síntesis evolutiva y los ingredientes de las distribuciones espectrales de energía, así como la información en términos evolutivos que puede extraerse de este tipo de datos.

A partir de las metalicidades medias, y usando datos previos del grupo para galaxias a redshifts menores, hacer un diagrama de Hubble hasta z=1 y comprobar si existe o no una dependencia de la distancia estimada de las SN-Ia con la metalicidad estimada de sus galaxias anfitrionas.

Tareas/hitos:

- Búsqueda de galaxias anfitrionas de supernovas Ia en los catálogos citados. Obtención de sus espectros
- Procesado de dichos espectros para su análisis
- FADO, incluir un espectro de prueba y aprender a usar el paquete, sacar resultados, realizar gráficos de evolución de Z* y de SF
- Realizar el mismo análisis para todas las galaxias encontradas. Obtener metalicidades medias, masas estelares y SF rate para todas ellas
- Búsqueda de las características de las SNIa para tener una tabla completa de datos SNIa-galaxias anfitrionas. Añadir datos de otros redshift y hacer un diagrama de Hubble. Chequear si hay una dependencia con la metalicidad

 

Directores: Mercedes Mollá (Mercedes.Molla@ciemat.es)  y Lluis Galbany (UGR)