Master Theses 2020/2021

Master Theses offered by CIEMAT-CFP Members for the academic year 2020/2021

1. Study of the cosmic-ray muon flux in the Short-Baseline Neutrino Program at Fermilab

The Short-Baseline Neutrino Program utilizes liquid argon time projection chambers to detect the neutrinos produced in the accelerators of Fermilab, the main laboratory for particle physics in the US. Because of the near-surface location, the detectors are subject to an intense flux of cosmic-ray muons that represent the main background for neutrino detection. The study of the cosmic-ray muon flux will allow us to better characterize and understand this background, reducing its impact on the search for physics beyond the Standard Model or astrophysical events with these detectors.

Supervisor: Dr. José I. Crespo-Anadón ( jcrespo@ciemat.es )

2. Cosmic-muon detection study with ProtoDUNE (Deep Underground Neutrino Experiment) at CERN

Abstract: 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 taken data with cosmic muons 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 different detector conditions to characterize the production, propagation and detection of the scintillation signal produced after the muon interación in the liquid argon.

Supervisor: Dr. Clara Cuesta (clara.cuesta@ciemat.es)

3. LiquidO: A Novel Neutrino Detection Technology

Abstract: LiquidO is an R+D project for the development of a new neutrino detection technology which uses opaque liquid scintillator, like milk or paraffin. This new technology represents a breakthrough with respect to the traditional neutrino detection with liquid scintillator, essential for future neutrino physics experiments requiring kton-mass detectors and isotope high loading, as neutrino-less double beta decay experiments. The tasks proposed in this End-of-Master project cover the development of simulations and the data analysis of a prototype that is currently taking data. LiquidO is an international collaboration that includes research institutes and universities from France, Italy and Japan.

Supervisor: Dr. Carmen Palomares Espiga (mc.palomares@ciemat.es)

4. Search for new physics processes beyond Standard Model of Particles and Interactions using pp collision data taken by CMS experiment at the LHC Collider (CERN)

Experimental evidence and theoretical developments during the last half-century have established the Standard Model (SM) as a reference theory, confirmed, up to now, with the recent discovery of the Higgs boson. However, some fundamental physics aspects seem to remain unexplained by this theory. One of the main objectives of the scientific program of CMS is to seek for evidence of new physics processes, beyond SM. In this work pp collision data collected by the CMS experiment at sqrt(s) = 13 TeV, as well as simulated collision events, will be analyzed in the context of a given search.

Supervisor: Dr. Begoña de la Cruz Martínez (begona.delacruz@ciemat.es)

5. Measurement of the quantum interference between top and anti-top quarks at the CMS experiment

The LHC collider is an extraordinary top quark factory, producing 10 top-antitop events per second in a standard colliding mode. Due to its huge mass, the top quark is the only one that behaves as a free quark in an effective way, hardly having strong interactions before it decays into lighter particles. This allows unique studies of quantum coherence in final states. In this work we will precisely quantify, using CMS experimental data, the level of quantum interference between top and anti-top quarks, contrary to a situation where these interferences are absent. This kind of correlations are useful to set constraints to physics effects coming from new potential interactions at high energy scales.

Supervisor: Prof. Juan Alcaraz Maestre (Juan.Alcaraz@cern.ch)

 

6. Measurement of bottom quarks charge asymmetry in future electron-positron colliders

Bottom quarks charge asymmetry (AFB(b)) is the electroweak observable measured in electron-positron collisions that shows largest deviations relative to standard model predictions. Its measurement, carried out in past colliders such as LEP and SLC, has generated several new physics hypothesis that could explain the deviation. The AFB(b) quantity will be again measured with an improved 10-fold precision at future electron-positron colliders. The proposed work is to measure the asymmetry using simulated events in the context of the current circular collider, FCC-ee, proposal, that will be able to produce several billions Z bosons in only a few working years. The results obtained will provide a realistic estimation of the final uncertainties at reach and their implications in terms of potential new physics.

Supervisor: Prof. Juan Alcaraz Maestre (Juan.Alcaraz@cern.ch)

7. 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.

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

8. 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

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

9. Development of algorithms based on artificial intelligence for direct dark matter searches with the DEAP and DarkSide-20k experiments

Artificial intelligence, and especially neural networks, are becoming a fundamental tool for analyzing large volumes of data, and particle physics is no exception. For this work, we propose the training and analysis of neural networks to help solve one of the greatest challenges in physics today: understanding the nature of Dark Matter. Among the most promising candidates are the Weakly Interacting Massive Particles (WIMPs), which we aim to detect using liquid argon-based experiments like DEAP-3600 and DarkSide-20k. The large amount of data generated by these experiments has to be processed and analyzed reliably and quickly, and artificial intelligence is playing an increasingly central role. The main goal of this work is the processing with neural networks of data from the DEAP-3600 experiment, which is being collected at SNOLAB laboratory (Canada), to improve the performance of classification and regression algorithms.

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

10. Cosmology with extragalactic radio surveys

Extragalactic surveys allow us to study the nature of the Universe by allowing us to solve mysteries like the nature of dark matter and dark energy. These surveys produce maps of the distribution of galaxies using instruments at different frequencies, for example optical or radio frequencies. The goal of this project is to study how well future radio extragalactic surveys can help us to constrain aspects like the expansion of the Universe. We plan to use cosmological theory of the growth of structures in the Universe and to use cosmological simulations to forecast the precision of future radio surveys.

Supervisor: Dr. Jacobo Asorey Barreiro (Jacobo.Asorey@ciemat.es)

11. Resolving the disks of stars: intensity interferometry with 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 2020/2021 season. This master’s thesis focuses analysis and scientific interpretation of the first data.

Supervisors: Dr. Juan Cortina Blanco,  Dr. Tarek Hassan Collados  (Juan.Cortina@ciemat.es)
Potential supervisor at UCM: Dr. J.L Contreras

12. 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

Supervisors: Dr. Miguel Ángel Velasco (MiguelAngel.Velasco@ciemat.es), Dr. Jorge Casaus (Jorge.Casaus@ciemat.es)

13. 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.

Supervisors: Dr. Jorge Casaus (Jorge.Casaus@ciemat.es), Dr. Francesca Giovacchini (Francesca.Giovacchini@ciemat.es)