Student talks

  1. Cenk Türkoğlu

    Simulation Backgrounds in CRESST-II Experiment Abstract: Dark matter is one of the biggest unknowns of our unive! rse. The CRESST experiment searches directly with CaWO4 based detectors for potential rare signals induced by dark matter particles. Understanding the background is crucial for such a rare- event search. For the recently finished CRESST-II data taking phase, the electromagnetic background component was the most prominent one. In this talk, I will present my studies of the contamination of CRESST-II experiment using the Monte Carlo simulation framework Geant4.

  2. Andreas Rappelt

    A novel method for comparing results of dark matter direct detection experiments. Abstract: Almost all results of dark matter direct detection experiments are presented by assuming the standard halo model, but it is well established that the Maxwell-Boltzmann distribution is only an approximation of the true velocity distribution. In this talk I present a novel method for comparing results from dark matter direct detection experiments, which is not plagued by uncertainties of the velocity distribution. After discretizing the velocity space, the linear programming algorithm is used to construct a velocity distribution, that minimises the expected rate a certain experiment, while simultaneously meeting the constraints obtained by other experiments. By comparing the minimised rate to the experimental result, one can determine whether the considered experiments are compatible or not.

  3. Matteo Puel

    Toy Monte Carlo simulation for a DM signal detected by Fermi-LAT Abstract: The purpose of my 3-months traine! eship at the Stockholm University is to make a toy Monte Carlo simulation in order to study the ability of the Fermi Large Area Telescope (LAT) instrument to discriminate a possible monochromatic gamma-ray line signal, coming from a Dark Matter (DM) annihilation process, from astrophysical background. This analysis is developed in the context of two different event classes: regular and \"Calorimeter-only (CalOnly)\" events.

  4. Johannes Herms

    Antideuteron prospects at present and future cosmic ray experiments Abstract: Cosmic ray antideuterons are a promising window for Dark Matter indirect detection, due to the very small expected background flux at low energies. We investigate different sources of galactic antideuterons and assess the possible signal at AMS-02 and the planned GAPS experiment, taking into account bounds on exotic fluxes of antiprotons obtained from recent AMS-02 data.

  5. Sebastian Ingenhütt

    Dark matter decays from non-minimal coupling to gravity Abstract: We consider scenarios where dark matter becomes ! unstable due to a non- minimal coupling to gravity. We show that the dark matter can decay into Standard Model particles with a lifetime which is potentially accessible to gamma-ray or neutrino telescopes. We determine the decay branching fractions in some simple scenarios and we set limits on the size of the dark matter non-minimal coupling parameter from observations.

  6. Pedro V. P. Cunha - Black hole shadows

    Abstract: There is an ongoing international project dubbed Event Horizon Telescope, which aims to observe the supermassi! ve Black Hole (BH) candidate Sgr A* in the center of our galaxy and obtain the first image of a BH shadow. For an observer, a shadow is a BH’s apparent shape in the sky due to gravitational lensing of nearby radiation, emitted by an external source. For Kerr space-time, which is the standard BH in astrophysics, it is possible to have a closed analytical form for the shadow. However, in general this is not possible and numerical methods are required. In practice, the null geodesic equations are integrated through a numerical procedure called backwards ray-tracing. Each light ray starts from the observer position and it is evolved backwards in time until its origin is determined. The gravitational lensing produced by a BH can also be studied through this analysis.

  7. Miguel Ramos Pernas - Strange physics at the LHCb

    Abstract: This talk will cover the main analyses that are being perform! ed at the LHCb experiment concerning strange particles decays. The s-d transition in the SM is very suppressed, so processes like Ks->mu+mu-, Ks(L)->pi0mu+mu- or Sigma+->pmu+mu- become very promising for the study of the Standard Model extensions, supersymmetry and extra-dimensions theories. Also, the determination of the K+ mass, last measured in direct decays in 1965, becomes crucial since the sensitivity of many measurements depends on m_K. Studies on the Ks->pi+pi-l+l- and Ks->l+l-l\'+l\'- decays are very interesting too, as they constitute very good channels to test the universal lepton coupling. Therefore kaon decays represent an excellent field of study, and the LHCb gives the opportunity to perform such measurements, adapting its functionality to the topology of such processes.

  8. Tiago Marques - Space Weather Impact on GNSS

    Abstract: Space weather is a term which describes variations in the ! Sun, solar wind, magnetosphere, ionosphere, and thermosphere, which can influence the performance and reliability of a variety of space-borne and ground-based technological systems and can also endanger human health and safety. My research focus is on ionosphere monitoring, namely TEC and scintillation measuring.

  9. Gasper Kukec Mezek - Primary particle identification of extensive air showers

    Abstract: Ultra High Energy Cosmic Rays (UHECR) are mostly protons or heavier nuclei that produce a large cascade of par! ticles upon interacting with atmospheric molecules called an extensive air shower (EAS). These EAS are then detected with Cherenkov water tanks and Fluorescence detectors that aim to reconstruct the energy, direction and type of primary UHECR.\r\nWith the use of a handful of detector observables that are sensitive to the type of primary particle, we might get some information on the physics of collisions between UHECR and atmospheric nuclei and on sources accelerating such cosmic rays.

  10. Carla Susete Gonçalves Francisco - The Higgs Boson and Statistics applied to Physics of elementary particles with Computational developments in R

    Abstract: Introduction to continuous probability distributions and the use of statistical software R to illustrate important aspects of them, to better understand the distribution and the essential role that nowadays computing plays in statistics area. Starting this topic with a brief introduction to continuous distributions and proceed with a more detailed analysis of some of these distributions such as the normal distribution, uniform distribution and the exponential distribution, developing the study of probability and continuous distributions. Although there are many others, we focused on three distributions largely used in the statistical universe. Special importance has been given to the normal distribution, the uniform distribution of continuous and continuous exponential distribution. The normal distribution wanted to illustrate their use through a real case that is at the forefront of scientific knowledge, which is the search for the Higgs boson and its close relationship with the statistics to be able to distinguish what in fact is presented as a new particle of what is just background noise. Examples were given to illustrate, using always the practical presentation of results with the use of R, several inherent in this distribution parameters as well as practical examples of how these parameters can be used to solve real problems. For uniform distribution we try to emphasize its importance for simulation, that generally all major simulation methods bot! h for continuous and discrete event based on continuous uniform distribution. Finally a practical example was given in solving a problem using statistical methods of R applied to this distribution. The exponential distribution we tried to show its valuable importance in modeling real situations of day-to- day activities such as queue management and also complex scientific issues, such as climate models. For all these distributions with the aid of R illustrated by graphs and some accounts, calculating the density of probability and quantiles attributes that define distributions in the study.

  11. Brais Palmeiro Pazos - Double beta decay search with NEXT

    Abstract: One of the main question that remains to b! e seen in Particle Physics is whether the neutrino is its own antiparticle (whether it is Majorana or Dirac). This answer will show us how to incorporate the neutrinomass inside the Standard Model. NEXT is a 100 kg enriched Xenon High Presure Gas Time Projection Chamber that uses a novel technique to find the hypothetical neutrinoless double beta decay of 136Xe. If found it, this will mean that the neutrino is a Majorana particle. NEXT experiment is expected to have an excellent energy resolution, <1% FWHM at Qbb=2.48 keV, and it will provide an extra rejection handle thanks to its excellent tracking capabilities.

  12. Goran Popara - Left-right symmetry and light window for right-handed neutrinos at LHC

    ABSTRACT Left-right symmetric models, while restoring the parity and addressing some of the unanswered questions in the Standard Model, also naturally embed the seesaw mechanism and open the possibility to directly probe the nature of neutrinos and their mass in the colliders such as LHC. After a brief description of the model and the constraints from flavor physics, an interesting lepton number violating process, which can be used to test both the left-right symmetry and Majorana nature of the neutrinos, will be discussed, along with the light collider window for the right-handed neutrinos at LHC.

  13. Luís Cebola - Beyond the Standard Model: Neutrinos Masses and Mixings

    Abstract: Lately particle physics and high energy physics have been some of the most discussed topics in science, mainly due to recent Nobel Prizes, awarded for the Higgs mechanism and neutrino oscillations. I will briefly present my work that focuses on Standard Model extensions and provides a viable framework to generate neutrino masses and also accommodates the oscillation data. Models with scalars bosons similar to the Higgs particle, as well as numerical approaches to the structure of the effective neutrino mass matrix will be outlined.