Master Theses 2022/2023

Master Theses offered by CIEMAT-CFP Members for the academic year 2022/2023

Development and study of a muon telescope with drift tube chambers

More than 25% of the Drift Tube chambers for the muon spectrometer of the CMS experiment at the LHC were assembled at CIEMAT. Using the same technology, four small-scale detection units were manufactured. These chamkers make up a portable cosmic muon detection system, or  “muon telescope”, that can be used for numerous applications, such as studies of cosmic radiation, test bench for the electronics of future CMS updates, muon radiography, etc. In the proposed master thesis, the student will participate in the detector development, its test system, data acquisition system and analysis software, thus allowing him/her to learn about the complete operation chain of a particle physics experiment. Moreover, she or he will carry out performance studies of the drift tube chambers and preliminary estimates of the viability of this experimental setup as muon radiography system.

Supervisor: Dr. Jesús Puerta Pelayo (CIEMAT) (

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 a 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. Roberto Santorelli (CIEMAT) ( ), Dr. Luciano Romero (CIEMAT) ( )

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. Vicente Pesudo (CIEMAT) ( ), Dr. Pablo García-Abia ( ) (CIEMAT)

Search for physics processes beyond Standard Model with the SBND experiment at Fermilab

Neutrino masses and their huge difference with those from the rest of elementary particles poses a strong suggestion towards existence of beyond Standard Model physics. The SBND experiment, a liquid-Ar time projection chamber located 110 m from the neutrino beam origin, at the Booster Neutrino Beam (BNB) in Fermilab (Illinois, EEUU), aims, among other things, to search for new physics processes. Within the current TFM the sensitivity to several extensions to the Standard Model will be studied.

Supervisor: Dr. José I. Crespo-Anadón (CIEMAT) (

Search for simultaneous production of two Higgs bosons decaying in two b-quarks and two tau leptons (HH->bbtautau) with data from the CMS experiment at LHC (CERN)

The simultaneous production of two Higgs bosons offers the possibility to study a fundamental parameter of the Standard Model, the so-called “Higgs self-coupling”, that describes the way the Higgs boson interacts with itself. The HH->bbtautau decay channel is one of the most promising ones for this study, as it is a relatively abundant final state and easy to be identified. This channel has been already studied at the CMS experiment at the LHC, though observation with 5 sigma significance has not been claimed yet.

This TFM will focus on upgrades foreseen for the data analysis, that will significantly improve the sensitivity to this process. In particular it will address improvements in the online selection of events (trigger) that allow identifying and collecting interesting events in a more efficient way, and the usage of new algorithms based on artificial intelligence (machine learning, ML) to help discriminate HH signal versus other Standard Model processes, with a similar topology.

Supervisors: Dr. Silvia Goy (CIEMAT) ( ), Dr. María Cepeda (CIEMAT) ( )

Sensibility to supernova neutrinos of the Deep Underground Neutrino Experiment

The Deep Underground Neutrino Experiment (DUNE) is a powerful tool to perform low energy physics searches. DUNE will be uniquely sensitive to the electron neutrinos coming from the burst of a core-collapse supernova. Detecting neutrinos from a supernova will bring information about the supernova itself, but also about the neutrino nature. Studies of the DUNE potential for different supernova models will be carried out to evaluate the sensitivity of DUNE to provide an insight on the core-collapse supernova explosion or neutrino physics.

Supervisor: Dr. Clara Cuesta (CIEMAT) ( )

LiquidO: A Novel Neutrino Technology

The unknowns in neutrino physics demand huge detectors (>kton), with high energy resolution and accurate particle identification. A simple and not costly detector fulfilling these requirements would be a game-changer in neutrino physics. 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. 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 (CIEMAT) (

Search for Dark Photons from the Sun with Spaceborne Experiments

Dark matter constituents may only interact with the Standard Model through the kinetic mixing of the so-called dark photons, i.e. the gauge bosons of a broken U(1) symmetry, with Standard Model photons. Within this scenario, dark photons are copiously produced in the annihilation of gravitationally captured dark matter in the Sun. These dark photons leave the Sun and decay into pairs of charged SM particles that can be detected by spaceborne cosmic ray detectors. The discovery potential of current experiments (AMS-02, DAMPE, CALET) and future instruments (HERD, ALADInO, AMS-100) will be investigated.

Supervisors: Dr. Miguel Angel Velasco (CIEMAT) ( ), Dr. Jorge Casaus (CIEMAT)  ( )

Gamma Ray Transients and Multi-messenger Physics with Spaceborne Experiments

Continuous monitoring of the high energy gamma ray sky is a powerful tool to identify transient events associated to the most energetic phenomena in the cosmos. As an example of this multi-messenger approach, the detection of the high-energy afterglow of the short gamma ray bursts associated to the electromagnetic counterpart of gravitational wave (GW) events may provide key information about the nature and location of the GW progenitor. The potential of future large field-of-view cosmic ray experiments (HERD, AMS-100) to detect transient gamma ray signals will be investigated.

Supervisors: Dr. Miguel Angel Velasco (CIEMAT) ( ), Dr. Jorge Casaus (CIEMAT) ( )

Study of the associated production of a vector boson (W or Z) and jets originated from heavy quarks (c or b) in proton-proton collisions at sqrt(s)=13TeV with data from the CMS experiment at the CERN LHC.

This is a high precision measurement in the context of the standard model of particle physics. The characterization of these processes is also critical to understand one of the most relevant backgrounds to the study of the Higgs boson properties in its decay channels into a pair of heavy flavour quarks (H --> bb, H --> cc). There remains a possible extension to the associated production of a W vector boson and two b jets.

Supervisors: Dr. Juan Pablo Fernández (CIEMAT) ( ), Dr. Isabel Josa (CIEMAT) ( )

Study of the coupling between the Higgs boson and the tau lepton for future e+e- colliders

The only established and measured coupling of the recently discovered Higgs boson to leptons, is the Higgs to tau (H-t) coupling. This coupling will be measured more precisely at the LHC Run3, and in its high-luminosity version, HL-LHC. However, it will be in a future electron-positron collider, at the TeV collision energies, when this coupling will be determined at a much higher resolution, enabling searches for deviations relative to Standard Model predictions. This TFM will focus in developping analysis based on simulated data from future e+e- colliders still in a conceptual and development phase.   

Supervisors: Dr. María Cepeda (CIEMAT) ( ), Dr. Juan Alcaraz (CIEMAT) ( )

Measurement of the production cross-section of electroweak vector bosons (W/Z) using data from pp collisions at sqrt(s) = 13.6 TeV from the LHC Run3

The proposal aims to determine the production cross section of electroweak bosons (W/Z) with the data collected by the CMS detector during 2022, in pp collisions at a sqrt(s) = 13.6 TeV, as part of the LHC Run3 operation. During the period 2018-2021 many upgrades have been implemented in the CMS detectors. In this TFM their performance will be studied, in terms of muon reconstruction and pT measurement. The selection of events containing muons will be optimized in view of the measurement of the production cross section of W and/or Z bosons, in their muonic decay, and at the new centre-of-mass energy at the LHC.

Supervisor: Dr. Isabel Josa (CIEMAT) ( )

Study of the process pp -> W -> muon +neutrino when the W boson is highly offshell, in view of searches for new physics processes beyond the Standard Model at the CMS experiment in the CERN LHC

A fundamental component of searches for new physics processes beyond the Standard Model (SM) is the comparison of experimental data coming from pp collisions at the CMS experiment in the CERN LHC, to SM predictions, mainly obtained from simulated data, looking for deviations in one or more relevant distributions. It is thus primordial to have at our disposal precise and reliable simulations of all the processes known at the SM. This TFM pursuits studying simulations at tree level (LO) and 1-loop level (NLO) of the pp à W àmuon +neutrino process, needed, among others, in searches for new massive vector bosons, W’.

Supervisor: Dr. Begoña de la Cruz (CIEMAT) ( )

Gravitational waves studies with data from the Virgo experiment

The CIEMAT Gravitational Waves group participates in the data analysis of the Virgo experiment. We are especially interested in fundamental physics studies, like dark energy, dark matter and the estimation of cosmological parameters. In this TFM, the student will contribute to stochastic background analyses, and in the search for signals without well-defined templates, like Supernovae explosion.  For these studies, we envisage introducing Machine Learning and Deep Learning techniques, focusing on Explainable Artificial Intelligence (XAI). XAI will be carried on to generate robust and unbiased classifiers and predictors, that allow identifying the most relevant variables for the predictions.

Supervisors: Dr Pablo Garcia (, Dr Carlos Delgado ( (CIEMAT)

Studies on the new muon trigger algorithm in CMS using collision data from LHC

The LHC (Large Hadron Collider) at CERN is planning an upgrade that will achieve a factor 10 in luminosity (10 times the number of collisions per second), so called HL-LHC. In this way, more precise measurements of elementary particles and unexpected process below the actual sensitivity reach will be possible. Selecting the best collisions is performed by the algorithms implemented in the Trigger systems, which need to be improved for this new challenging scenario. CIEMAT has developed a new muon trigger algorithm for the CMS detector capable of operating at the maximum luminosity and moreover, providing ultimate resolutions. In this TFM the student will approach the selection process required for the trigger systems of an experiment and learn how to study and improve the performance of the CMS muon trigger both in Montecarlo and collision samples.

Supervisors: Dr Alvaro Navarro Tobar (, Dra. Cristina Fernández Bedoya  ( (CIEMAT)