Student: Clara Lasaosa García.
Director(s): Jordi Duarte Campderros and Alicia Calderón Tazón.
Contact: firstname.lastname@example.org and email@example.com
The High Luminosity LHC will force their experiments to cope with harsh radiation environments, in particular within the detectors closest to the interaction
point. Pixel detectors in CMS will have to survive a fluence in excess of 1E16 neutron equivalent per centimeter squared. CMS, like ATLAS, will fill their
innermost layers of the tracker with a new radiation-tolerance technology: the 3D pixel sensors. This technology must be implemented in the CMS full simulation.
The implementation will enable the optimization with the Monte Carlo simulation of the several sensor and modules layouts currently being considered, and the
potential hit reconstruction algorithms to be used. The aim of this project is to include the 3D sensor pixel technology into the CMSSW full simulation and create
the procedures to consistently validate the software as well as the models by comparing with data.
Student: Laura Victoria Trujillo Taborda.
Director: Jesús Manuel Vizán García.
Since the observation of a Higgs boson with a mass around 125 GeV during the Run 1 of the Large Hadron Collider (LHC), many of its properties have been
studied in detail and a large number of searches for new particles have been carried out without finding evidence of new physics or significant deviations
from the Standard Model (SM). However, and despite the enormous success of the SM describing a vast range of phenomena, several theoretical considerations,
like the problems for the SM to explain the observed mass of the Higgs boson in the presence of quantum corrections (hierarchy problem), motivate searching
for physics beyond the SM (BSM) with the data from the Run 2 of the LHC, and also in the future Run 3 and during the High-Luminosity LHC period.
In this context, it is important to consider the possibility that the lack of evidence for physics BSM phenomena is due to the fact that those phenomena could
manifest themselves via rare signatures at LHC, being the presence of new particles with a relatively large lifetime one of the most attractive options. The
goal of the proposed work is the study of this type of searches when the long-lived particle decays to pairs of displaced charged leptons (electrons or muons).
The work to be carried out will be based on an ongoing analysis of this kind making use of the total amount of data collected during the LHC Run 2 by the CMS
experiment, with the objective of improving different aspects of the search. Several options can be considered: the optimization to signals where the displacement
is moderate, the improvement of the efficiency reconstructing the signal events or optimizations in the background estimation. The expertise acquired until the
beginning of the project will determine the aspects for which more effort will be devoted.
Student: Guillermo Pascual Cisneros.
Director: Francisco Javier Casas Reinares.
Cosmic Microwave Background (CMB) polarization measurement is a unique tool for the study of the inflationary process of the Universe, in particular by means
of the polarization B-mode characterization. In order to reach the required instrumental sensitivity, as a function of the frequency range of interest, diverse
technologies can be used. For frequencies higher than 50 GHz, bolometric technology (“Transition Edge Sensors” or TES) an others similar (“Kinetic Inductance Detectors”
or KID) are the most adequate, due to their sensitivity and the capability to fabricate hundreds of detectors in one only wafer of semiconductor material. However for
frequencies lower than 50 GHz, the use of different technologies as Microwave Photonics and Digital ones, results very promising due to different aspects as the
capability of correlating and detecting hundreds of ultra-wide-band microwave signals, the first of them, and the capability of digitizing wide-band microwave signals
and implementing different reception structures in a simple and flexible way, the second one. The proposed work consists in the identification of reception and CMB
polarization measurement structures, using both technologies, in order to perform a comparative study and to discover which of them is the most appropriate as a
function of the instrument and even the frequency of interest.
Student: Roaa Kheder.
Director: Pablo Martínez Ruiz del Árbol.
Particle Physics experiments rely on Monte Carlo simulations to provide the expectations from the Standard Model that can be compared to data for hypothesis testing.
The production of an accurate and realistic Monte Carlo simulation is a key element of physics analyses. This work aims at using a Generative Adversarial Neural Network
(GANN) to produce a more realistic simulation by learning data features from a data control sample. A search for dark matter in association with top quark-antiquark
pairs will be used as the benchmark analysis to test the performance of the GANN.
Student: Jazmín Morales Morales.
Directors: Rocío Vilar Cortabitarte and Amparo López Virto.
This research project proposes to reproduce a test chamber setup of the DAMIC-M (DArk MAtter In CCDs at Modane) to study in detail the CCDs (Charge Coupled Device) sensors
used in the experiment that will start in 3 years from now. The setup will start from scratch mounting all the different components to get the first signal and
images. This would be the main part of the project. One of the main issues for these CCDS is the understanding of the Dark Current in great detail. During the
project the dark current will be studied using data from the DAMIC (DArk MAtter In CCDs at SNOLAB) experiment that has been taking data since 2017.
Student: Hamza Hanif.
Directors: Rocío Vilar Cortabitarte and Alicia Calderón Tazón.
In this project, it is proposed to measure the production cross section of the top pair in proton-proton collisions with an energy of 13 TeV using the LHC data
collected with CMS detector. The top quark can decay in several ways, here the fully leptonic decay will be used. Study of selection to discriminate signal
from background, efficiencies, simulations and uncertainties are the main part of the project. Once these components are understood, we can obtain the
measurement of the production cross section.
Student: Mario Gómez Señas.
Director(s): Jesús Manuel Vizán García and Pablo Martínez Ruiz del Árbol.
Every fundamental particle in the standard model of particle physics has been discovered. Due to the shortcomings from which this theory suffers,
finding a new, more general theory is necessary. This new theory should perform as well as the Standard Model did and also provide with solutions
to open questions such as the hierarchy problem or the dark matter.
Supersymmetry is a promising theory in this sense, and we might now lay on the edge of observing its manifestations. In a few years time, the HL-LHC
will start running. It is a new upgrade version of the LHC, the largest collider ever built, and will be able to produce a higher amount of data to
elucidate this theory's likelihood or others'.
One key process to detect supersymmetry is the production of scalar stop quark pairs, which would decay into a top quark and an invisible neutralino.
This work reproduces a stop quark search performed in the CMS experiment at CERN. It determines exclusion limits to the production cross section of this
process and predicts future limits attainable with data from HL-LHC.
Student: Lorenzo Barquín González.
Director(s): Silvia Mateos Ibáñez and Francisco Jesús Carrera Troyano.
One of the most important questions in modern astrophysics is the study of the formation and evolution of galaxies throughout the history of the Universe.
In the last decades, several pieces of evidence have been found that support a coevolution of galaxies with the supermassive black hole (SMBH) that most
of them (maybe every galaxy) have in their centres. Consequently, to make progress in this field it is necessary to understand the properties of these SMBH.
Particularly of those in an active phase of growing (increasing their mass) accreting material from the host galaxy. They are the so-called active galactic
nuclei (AGN). Of these, the most highly obscured systems are of special interest, since it is believed that during this highly obscured phase the relationship
between SMBHs and their hosts was established. The obscuration is caused by a dust and gas structure, the so-called torus. The highly obscured AGN (known as
Compton thick (CT)) are lost in optical surveys and, to a lesser extent, in X-ray surveys as the radiation emitted at these frequencies is absorbed.
These AGN could be detected in mid-infrared wavelengths, where obscuration effect are less important. However, their study in X-rays is fundamental to determine
the obscuration level. There are empirical relations in the literature that relate the mid-infrared and X-ray luminosity of AGN. The first objective of this work
is to check whether these relations describe correctly the relation between luminosities for mid-infrared selected AGN samples (as the one used in this work) and
to obtain our own relation otherwise. The second objective is to estimate a lower-limit for the obscuration for mid-infrared selected AGN not detected in deep
X-ray exposures with the X-ray observatory XMM-Newton. The last objective is to estimate the necessary exposure times for the detection of this kind of objects
with the X-ray observatories XMM-Newton and Athena.
To accomplish these scientific objectives we have selected a sample in the mid-infrared composed of 91 AGN: 68 detected in X-rays with XMM-Newton, 3 detected in
X-rays but with low-quality X-ray spectra and 20 AGN with no X-ray detection. As it is a sample selected in the mid-infrared it is expected to include objects with
obscuration levels all over the parameter space. These AGN (23) are our sample of CT candidates. The X-ray undetected AGN and those with low-quality X-ray spectra
are expected to be highly obscured or CT. For the undetected AGN we have upper-limit estimated for their X-ray fluxes. For those AGN with low-quality X-ray spectra,
we have the observed luminosity (not corrected by obscuration). These measurements will be used to put constrains on the level of obscuration for these sources.
First, we obtained the intrinsic X-ray luminosity (corrected by obscuration) of the CT candidates. To do that we check if the empirical relations of the literatura
between X-rays and mid-infrared luminosities are valid for mid-infrared selected samples. As previous relations in the literature overestimate the X-ray luminosity
of our sources we obtained our own empirical relation using the X-ray detected AGN in our sample. We obtained the intrinsic X-ray luminosity for the CT candidates
assuming they follow the same relation as the X-ray detected AGN. Then the lower-limit of the obscuration of the AGN was estimated. We modelled their X-ray emission
with a torus model and we used the intrinsic X-ray luminosity derived for every object from their mid-infrared luminosity. We ran simulations increasing the obscuration
until the upper-limit flux or the observed luminosity was reached. Once we know the obscuration we estimated the exposure time needed to detect them with the X-ray
observatories XMM-Newton and Athena. To do so we run new simulations with the same model imposing a signal-to-noise ratio threshold equal to 5 to accept the
In this work we have found that: a) mid-infrared selected AGN are intrinsically weak in X-rays in comparison with X-ray selected AGN, consequently traditional
empirical relations overestimate their intrinsic X-ray luminosity; b) the absorption of the CT candidates is high or even extreme is most objects; c) it is not
posible to detect most obscured AGN with the actual generation of X-ray observatories in a reasonable exposure time; d) Athena will be able to detect such highly
obscured AGN population routinely with the extragalactic surveys planned for the mission.
Student: Jorge Luis Orellana Cruz.
Director(s): Francisco Jesús Carrera Troyano and Amalia Corral Ramos.
Obscured active galactic nuclei (AGNs) are a key ingredient in galaxy formation and evolution models. X-rays, thanks to their high penetration power, remain
the most efficient method to detect and characterize them. In this work we propose to develop an automatic method to derive the redshift to these AGNs based
on X-ray spectroscopy. Thus, we take advantage of the fact that one of the most common spectral characteristics of these AGNs is the presence of a very intense
fluorescence emission line of the iron FeKα at energies between 6.4 and 6.9 keV. The method is based on the detection of emission peaks in the observed X-ray
spectra, in principle associated with the FeKα line. The improvement consists of filtering to reduce noise using fourier techniques. This improvement has been
performed by using AGN Compton Thick simulations at various redshifts, luminosities and column densities.
Student: Patricia Diego Palazuelos.
Director(s): Patricio Vielva Martínez.
The most promising channel to detect the Primordial Gravitational Wave background, the smoking gun observable proving that an inflationary period took place,
lies in the B-mode polarization of the Cosmic Microwave Background (CMB). However, due to its very low amplitude, the imprint it leaves on CMB polarization is
vastly obscured by galactic microwave emissions and the B-mode polarization produced by weak gravitational lensing. As CMB experiments and component separation
techniques are approaching the sensitivity at which lensed B-modes become the main obstacle in the detection of the primordial B-mode, we decided to study how
well could the lensing effect be reversed for CMB maps with the noise levels that may be expected from future missions, and using high-quality reconstructions
of the lensing potential. We found that lensing potential reconstructions must reach around a 500δ signal-to-noise ratio themselves to reduce the lensed B-mode
spectrum to half its amplitude, conditions in which a 2δ detection of an r = 6 X 10-4 would be possible. For such reconstructions to be internally produced from
the CMB, CMB maps must have an instrumental noise below the 1μK. arcmin level.
Student: Efrén Navrrete Ramos.
Director(s): Gervasio Gómez Gramuglio and Iván Vila Álvarez.
For the high-luminosity LHC upgrade (HL-LHC), the ATLAS and CMS experiments are planning to include dedicated detector systems to measure the arrival time of
Minimum Ionising Particles (MIPs). Such systems should provide a timing resolution of 30 ps per MIP. State-of-the-art timing technologies integrating Silicon
photo-multipliers and plastic scintillators do not tolerate the hadron fluences expected at the end-cap detector regions (up to 3x10^15neq/cm2). To cope with
these requirements, a Silicon sensor with integrated signal amplification, the Low Gain Avalanche Detector (LGAD) is the baseline sensing technology of the
end-cap timing detector systems at HL-LHC. A detailed study of LGAD pad-like sensors manufactured at Instituto de Microelectrónica de Barcelona - Centro
Nacional de Microelectrónica (IMB-CNM) and irradiated at CERN’s PS-IRRAD proton facility up to a fluence of 1x10^14neq/cm2 is carried out in this project.
Student: Agustín Lantero Barreda.
Director(s): Rocío Vilar Costabitarte and Nuria Castelló Mor.
This project is the base for the elaboration of a Data Quality Monitoring System (DQM) for the direct search Dark Matter experiment: DAMIC (Dark Matter in CCDs).
In this project, different variables are going to be studied to see to identify which ones characterised the data and perform a simple statistic test that allows
to distinguish good and bad images. To be able to find possible elements that can be used to classify the images taken by the CCD, the data reading process has
been studied along with the different variables taken from it.
Student: Fernando Martín Salamanca.
Director(s): Diego Herranz Muñoz.
Clusters of galaxies are the most enormous structures that are bounded by gravitational interaction and, because of that, they are some of the most important
objects of study in modern Cosmology. In this work some physical effects that leave its own trace in Cosmic Microwave Radiation will be studied, both
temperature and polarization. Once these effects are characterized, we will perform a new statistical tool to detect galaxy clusters taking into account its
temperature and polarization signal, opposed to nowadays tools that only take into account the temperature contribution.
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