À descoberta da natureza do neutrino: decaimento beta duplo sem neutrinos
O decaimento beta duplo sem neutrinos é um dos tópicos mais interessantes da física de partículas contemporânea. A sua observação provaria a existência de nova física para além do modelo padrão (SM), e mostraria que o neutrino é uma partícula de Majorana -- isto é, é a sua própria anti-partícula. Provaria ainda a existência de processos que violam a conservação do número leptónico, suportando a ideia de que os leptões podem ter contribuído também para a assimetria entre matéria e anti-matéria observada no Universo. Este decaimento está previsto em extensões do SM que também conseguem explicar a massa extremamente pequena dos neutrinos (6 ordens de grandeza menor que a do electrão). A sua taxa de ocorrência pode ser associada à chamada massa efectiva de Majorana, uma combinação das 3 massas de neutrinos que pode ser usada para determinar se estas massas seguem uma hierarquia normal ou inversa (apesar de não permitir determinar os seus valores absolutos). Várias experiências, entre as quais LZ, procuram este decaimento extremamente raro. O detector LZ foi desenvolvido com o objectivo principal de procurar interacções directas de matéria escura com o material de detecção (xénon líquido), mas dada a sua grande sensibilidade pode também ser usado para estudar outros processos físicos, como o decaimento beta duplo sem neutrinos. O isótopo Xe-136 é um conhecido emissor beta duplo com emissão de neutrinos, e portanto poderá também decair sem emissão de neutrinos, sendo atualmente o isótopo que permite restringir mais fortemente os valores da massa efectiva Majorana. Com o início da tomada de dados de LZ previsto para o final deste ano, os alunos irão avaliar a sensibilidade de LZ para observar este decaimento no Xe-136 analisando dados simulados da experiência.

Experiência : DarkMatter
Local : Coimbra
Supervisor(s) : Alexandre Lindote, Paulo Braz
Email : alex@coimbra.lip.pt
Vagas : 3
Duração/Datas : July

DETECÇÃO DIRECTA DE MATÉRIA ESCURA COM A EXPERIÊNCIA LUX-ZEPLIN
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Experiência : DarkMatter
Local : Coimbra
Supervisor(s) : Cláudio Silva - Paulo Bras
Email : claudio.silva@coimbra.lip.pt
Vagas : 3
Duração/Datas : Jul-Ago

Estudos para controlar a radiação de fundo na verificação experimental do efeito Migdal
A composição da maior parte da matéria escura observada no universo é ainda desconhecida, e considera-se que é feita de um novo tipo de partículas elementeares além do Modelo Padrão. Neste contexto, o efeito Migdal é uma predição, ainda não confirmada experimentalmente, que permeteria procurar partículas de matéria escura que tivessem massa por baixo de 1 GeV. Este estágio oferece contribuir a experiência MIGDAL, que tem o objetivo de verificar este efeito. Concretamente, a/o estudante vai tratar o impacto da radiação de fundo na experiência, usando simulações de Monte Carlo, e estudará os meios para controlar esse impacto. Esta tarefa é essencial para poder confirmar o efeito Migdal.

Experiência : DarkMatter
Local : Coimbra
Supervisor(s) : Elías López Asamar
Email : easamar@coimbra.lip.pt
Vagas : 1
Duração/Datas : July

Predição do efeito Migdal nas calibrações com neutrões em LZ
A composição da maior parte da matéria escura observada no universo é ainda desconhecida, e considera-se que é feita de um novo tipo de partículas elementeares além do Modelo Padrão. Neste contexto, a Colaboração LZ está a construir a experiência mais sensível de sempre para estudar a existência de partículas de matéria escura que tivessem massa na escala dos GeV. A sensibilidade desta experiência pode ser ainda maior se as predições do efeito Migdal são confirmadas. Este estágio oferece estudar se as calibrações com neutrões nesta experiência poderão usar-se para determinar a resposta do detector ao efeito Migdal. A/o estudante usará simulações para calcular o ritmo de interações no detector devido à fonte de neutrões, e combinará esse resultado com as predições do efeito Migdal.

Experiência : DarkMatter
Local : Coimbra
Supervisor(s) : Elías López Asamar
Email : easamar@coimbra.lip.pt
Vagas : 1
Duração/Datas : July

Análise de dados com a experiência AMS
A experiência AMS (ver link da nasa por exemplo, http://ams.nasa.gov/) encontra-se instalada na estação espacial internacional desde Maio de 2011 a recolher dados, isto é, raios cósmicos - maioritariamente protões - que atravessam o detector e nele deixam sinais. AMS possui todas as características de um detector de partículas e permite por isso, a identificação dos diferentes tipos de partículas que o atravessam: protões, electrões, positrões, antiprotões, hélios, ... A instalação do detector fora da atmosfera terrestre transforma-o num observatório único do Universo e onde se esperam contribuições para o problema "de que é feita a matéria escura?" Para além disso, AMS permitirá medir com uma resolução nunca antes alcançada, os espectros das diferentes partículas constituintes dos raios cósmicos até energias de alguns TeV. AMS detecta e regista cerca de 500 acontecimentos por segundo. Isto corresponde a cerca de 15 mil milhões de acontecimentos acumulados por ano, dos quais cerca de 90% são protões, 1% electrões, 0.1% positrões, 0.01% antiprotões, etc. The main topic we will be addressing is the simulation of mass-based reference distributions (templates) measuring the abundance of isotopes He3 and He4 in the Helium cosmic-ray flux. About 10% of all cosmic particles are helium (Z=2), they are composed mainly by He3 and He4 isotopes and the ratio He3/He4 varies from 10 to 20%, as a function of magnetic rigidity. Taking into account uncertainties in the measurements of both velocity and magnetic rigidity, mass-based distributions can be developed and applied to data in order to statistically determine the populations of these isotopes in the cosmic-ray helium flux. The students are proposed to develop a small Helium (and its isotopes) flux simulation which reproduces AMS-02 data in order to estimate the He3/He4 ratio. (alunos 3º, 4º anos)

Experiência : AMS
Local : Lisboa
Supervisor(s) : Fernando Barão; Miguel Orcinha
Email : fernando.barao@tecnico.ulisboa.pt
Vagas : 2
Duração/Datas : 1-2 meses - Julho, Setembro (até ao início das aulas)

Development of a next-generation detector concept to detect astrophysical gamma-rays
At LIP, we are deeply involved in the design of the next-generation gamma-ray observatory that will be built in South America to survey and monitor the Southern sky. To be able to detect gamma-rays from the lowest energies (100 GeV) up to the highest (10 PeV) the experiment has to be placed at high-altitude (~5000 m) and cover huge areas (~5 km^2). Such poses strong requirements to the detector design and the array layout configuration, which our group is tackling through the use of state-of-the-art Monte Carlo simulations and the development of innovative data analysis. The challenge we pose to any student interested is to help us to design this next-generation detector and work on the development of shower reconstruction algorithms to identify the nature of the radiation/particle that generated the shower and with this increase the sensitivity of the observatory to gamma-rays.

Experiência : SWGO
Local : Lisboa
Supervisor(s) : Ruben Conceição, Bernardo Tomé, Mário Pimenta
Email : ruben@lip.pt
Vagas : 2
Duração/Datas : 1/7 to 15/09. Two weeks of holidays in August (TBD).

Hunting Forbush Decreases in the inner Solar System
Forbush Decreases (FD) are the observed drop in cosmic ray fluxes associated with the shock and/or ejecta of an Interplanetary Coronal Mass Ejection (ICME). They provide an indirect way to obtain information about ICMEs and their propagation throughout the solar system. So far, FDs have been studied extensively with neutron monitors on Earth. However, they also offer the possibility to study ICMEs at different points of the solar system due to their interaction with cosmic rays and subsequent change in the response of particle detectors and radiation sensitive components. In fact, recent measurements of an ICME by several missions already showed that they can be used to study its properties such as angular extension and constraint propagation models. The BepiColombo mission, currently on its way to the Hermean system, carries a radiation monitor, BERM, that is capable of measuring energetic electrons, protons, and heavy ions. While the detector was designed to measure Solar Particle Events, it has been measuring Galactic Cosmic Rays (GCRs) during its cruise of the Solar System. In this research project, the student will model GCR flux over time, and look for FDs in the data.

Experiência : SpaceRad
Local : Lisboa
Supervisor(s) : Marco Pinto, Patrícia Gonçalves
Email : mpinto@lip.pt
Vagas : 2
Duração/Datas : June-August (negotiable)

Identifying Hidden Particles with Machine Learning at SHiP
The Search for Hidden Particles (SHiP) experiment will be a next generation fixed target experiment in the intensity frontier, with the primary goal to discover relatively light long-lived particles from beyond the Standard Model (Hidden Sector), capable of explaining the origin of dark matter, matter-antimatter asymmetry of our Universe, neutrino masses and inflation. The experiment will be located in a new beam dump facility at CERN where it will use the high-intensity beam of 400 GeV/c protons (4 x 10^13 protons/second) from the SPS accelerator. The selected student will use machine learning techniques in order to distinguish between several types of HS particles with similar decays that will be probed at SHiP. To do this, by utilizing the kinematic properties of the particles expected to be found at SHiP, the students will explore the architecture of Neural Networks so as to maximize the distinction between Heavy Neutral Leptons, Dark Photons and Neutralinos. The goal is to provide an optimized guess of the particle being reconstructed based on the data gathered by the detectors.

Experiência : SHiP/SND@LHC
Local : Lisboa
Supervisor(s) : Guilherme Soares, Nuno Leonardo
Email : gsoares@lip.pt
Vagas : 2
Duração/Datas : July-August

Investigation of the muon puzzle at the Pierre Auger Observatory
The Pierre Auger Observatory is the largest particle detector in the world. It was built to detect and study so-called ultra high energy cosmic rays (UHECR). These are particles that are produced under unknown circumstances somewhere in the universe, presumably under the most extreme conditions. The energy of UHECRs by far exceed anything that we can achieve in our laboratories on Earth. As the CRs interact in the atmosphere their energy is converted into new particles, mostly photons and electrons (EM particles) and muons. One of the key results of Auger is the discovery that the number of muons produced in the interactions of UHECRs is much larger than expected. A recent study showed that fluctuations in the number of muons do behave as expected. The goal of this project is to extend the muon analysis with additional measurements of EM particles and study the correlation between EM and muon observables of UHECRs.

Experiência : Auger
Local : Lisboa
Supervisor(s) : Ruben Conceição, Lorenzo Cazon, Felix Riehn
Email : ruben@lip.pt
Vagas : 1
Duração/Datas : June to mid August

Muografia: simulação da sensibilidade do telescópio de muões
A muografia é uma técnica semelhante à radiografia que utiliza os muões criados em abundância na atmosfera pelos raios cósmicos, como uma fonte de radiação natural, para fazer imagens de grandes estruturas. O LIP tem um telescópio de muões a adquirir dados no seu laboratório, que posteriormente será colocado a fazer uma observação em campo, no interior da Mina dou Lousal. O objetivo deste estágio é desenvolver a simulação que representa a resposta do telescópio e comparar com os dados recolhidos no laboratório. O resultado final será usado na preparação da campanha a desenvolver na mina.

Experiência : Auger
Local : Lisboa
Supervisor(s) : Sofia Andringa, Pedro Teixeira
Email : sofia@lip.pt
Vagas : 3
Duração/Datas : June to mid-August

Neutron data from the SNO+ neutrino detector
As of April 2021, the SNO+ experiment reached an extremely important milestone: the complete filling of its detector with liquid scintillator. This event opens the way to exciting physics analyses, such as the measurement of antineutrino interactions. A key ingredient for this analysis is the detection of neutrons. The goal of this project is to compare the first neutron calibration data (energy, time and spatial distributions) with the expected detector model and identify the parameters that require better tuning.

Experiência : Neutrinos
Local : Lisboa
Supervisor(s) : Valentina Lozza, Sofia Andringa
Email : sofia@lip.pt
Vagas : 2
Duração/Datas : June to mid-August

Pierre Auger vs. The Machine: towards validation of deep-learning based reconstruction of ultra-high energy cosmic rays with new data from the Pierre Auger Observatory
Ultra-high energy cosmic rays are detected at the Pierre Auger Observatory by observing the particle showers that are induced when cosmic rays enter the atmosphere. One of the components of the Pierre Auger Observatory is the surface detector array that measures the particles arriving at the ground. Based on the distribution of the signals in the detectors (in time and space) the primary cosmic ray is reconstructed (direction, energy, mass). A deep-learning based method that promises to significantly enhance the sensitivity of the reconstruction has recently been developed. The goal of this project is to validate this algorithm by comparing it with data from the new array of scintillator detectors and the array of resistive plate chamber detectors.

Experiência : Auger
Local : Lisboa
Supervisor(s) : Felix Riehn, Ruben Conceição, Lorenzo Cazon
Email : friehn@lip.pt
Vagas : 2
Duração/Datas : June to mid August

Desenvolvimento de uma interface para analisar eventos do Observatório Pierre Auger, para uso em Masterclasses
O Observatório Pierre Auger, localizado na Argentina, consiste na maior experiência do mundo dedicada à detecção de raios cósmicos de energia extrema. No início de 2021, 10% dos dados desta experiência foram abertos ao público, para investigação e divulgação. Neste estágio, irá ser concebida e desenvolvida uma plataforma gráfica para analisar estes dados, direccionada para a utilização em edições futuras das masterclasses internacionais em física de partículas.

Experiência : Auger
Local : Minho
Supervisor(s) : Henrique Carvalho, Raul Sarmento
Email : raul@lip.pt
Vagas : 2
Duração/Datas : Datas flexíveis (Maio a Julho)

Optimização da muografia
A muografia é uma técnica semelhante à radiografia, que utiliza muões como uma fonte de radiação natural abundante para fazer imagens de grandes objetos. Nas suas instalações de Coimbra, o LIP montou um telescópio de muões que está a adquirir dados para produzir muografias do edifício. Neste estágio, irão ser desenvolvidas análises de dados para optimizar os parâmetros de operação do telescópio e aperfeiçoar as imagens produzidas.

Experiência : Auger
Local : Minho
Supervisor(s) : Sofia Andringa, Raul Sarmento
Email : raul@lip.pt
Vagas : 2
Duração/Datas : Datas flexíveis (Junho a Julho)

Pesquisas de multi-mensageiros astrofísicos de altas energias
A observação de ondas gravitacionais impulsionou as pesquisas por multi-mensageiros astrofísicos, estabelecidas através da comunicação de observatórios e telescópios espalhados por todo o mundo. Neste estágio, irão ser revistos os mecanismos e os resultados destas pesquisas, assim como exploradas as potenciais fontes de multi-mensageiros de altas energias.

Experiência : Auger
Local : Minho
Supervisor(s) : Raul Sarmento
Email : raul@lip.pt
Vagas : 2
Duração/Datas : Datas flexíveis (Junho a Julho)

Calibração de detetores RPC para muografia
A muografia é uma técnica de criação de imagem semelhante à radiografia, mas utilizando muões produzidos por raios cósmicos na atmosfera terrestre. A alta taxa de muões que chegam ao solo e a sua capacidade de penetração na matéria permitem criar imagens de grandes estruturas: por exemplo, edíficios ou minas. Neste projeto far-se-á a calibração de um telescópio de muões a funcionar nos laboratórios do LIP em Coimbra. O telescópio é composto por Câmaras de Placas Resistivas (RPC), que contém um gás que é ionizado pela passagem do muão. A posição de passagem em quatro planos consecutivos é detectada em "pixeis". A calibração pretende caracterizar e uniformizar a resposta em pixeis de diferentes formatos - usando os sinais do próprio telescópio e outras medições adicionais. O objetivo é melhorar a sensibilidade das imagens do efíficio do Departamento de Física, antes de o telescópio ser usado noutros locais.

Experiência : DetLab
Local : Coimbra
Supervisor(s) : Alberto Branco, Paolo Dobrilla, Sofia Andringa
Email : alberto@coimbra.lip.pt
Vagas : 2
Duração/Datas : Aproximadamente 1-2 meses, datas flexíveis

Desenvolvimento de uma nova tecnologia para detetores de neutrões
Atualmente estamos a desenvolver uma nova tecnologia para detetores de neutrões térmicos em colaboração com parceiros internacionais de grandes institutos para a investigação com neutrões, como por exemplo, do reator nuclear Heinz Maier-Leibnitz (FRM II) na Alemanha, do ISIS Neutron and Muon Source na Inglaterra e da ESS - European Spallation Source na Suécia, sendo esta a maior infra-estrutura dedicada à ciência atualmente em construção na Europa. O aluno participará nos trabalhos de investigação em curso no grupo, envolvendo simulação e otimização de detetores de neutrões baseados em câmaras de placas resistivas (RPCs), utilizadas na física das altas energias e astro-partículas, combinadas com conversores de neutrões do estado sólido (10B4C). O aluno terá ainda a oportunidade de participar no desenvolvimento de um protótipo de um detetor para neutrões térmicos, atualmente em curso. Participará em testes experimentais com fontes radioativas, bem como na recolha de dados e sua análise tendo em vista a caracterização da resposta do detetor em face dos princípios físicos envolvidos no seu funcionamento.

Experiência : nDet
Local : Coimbra
Supervisor(s) : Luís Margato e Andrey morozov
Email : margato@coimbra.lip.pt
Vagas : 3
Duração/Datas : 1-2 meses, datas flexíveis

Muões num balão: medidas do fluxo de muões até à estratosfera
A maioria dos raios cósmicos que chegam à Terra são produzidos por explosões de supernovas na nossa galáxia. Cerca de 90% são protões, 9% são núcleos de hélio e os restantes são núcleos mais pesados. Quando estas partículas interagem com a atmosfera, dão origem a um “chuveiro” de partículas, incluindo piões e kaões que rapidamente decaem dando origem a muões (as únicas partículas carregadas resultantes da interacção dos raios cósmicos que chegam ao solo). Os muões são partículas fundamentais e pertencem à classe dos leptões, tendo carga eléctrica +1 ou -1, uma massa cerca de 200 vezes maior que a do electrão e são também instáveis: o seu tempo de vida em repouso é de cerca de 2.2 µs, decaindo para um electrão, um neutrino e um anti-neutrino. Dado que são produzidos acima de 10 km de altitude, não se esperaria, de acordo com a física clássica, que chegassem à superfície da Terra em grande número. No entanto, dada a sua energia muito elevada, a dilatação relativista do tempo aumenta o seu tempo de vida, sendo possível observar um fluxo de aproximadamente 1 muão/cm2/min ao nível do mar. Durante este estágio os alunos irão ter formação básica em Física de Partículas e detectores associados, bem como estudar a formação de chuveiros de partículas pela interacção de raios cósmicos na atmosfera. Em simultâneo, irão preparar a electrónica e software associado para aquisição de dados de dois pequenos detectores de partículas que foram construídos por alunos durante estágios de anos anteriores. O objectivo final é montar um sistema de aquisição de dados portátil que permita a medição do fluxo de muões, e preparar toda a logística necessária (e.g. localização por GPS, comunicação rádio para transmissão de dados) para enviar (e recuperar) o setup experimental num balão estratosférico de forma a medir a variação do fluxo de muões com a altitude até cerca de 30 km.

Experiência : CCMC
Local : Coimbra
Supervisor(s) : Alexandre Lindote, Filipe Veloso, Francisco Neves
Email : alex@coimbra.lip.pt
Vagas : 3
Duração/Datas : July

Non invasive temperature monitoring device
Non-invasive temperature measurement has many applications, from biology (e.g. monitoring of nesting birds) to industry (e.g. products in a conveyor belt) or medicine (e.g. fever check). Recent developments in software tools for the recognition of patterns in images (e.g faces or objects) allows for fast processing of complex scenes acquired using a simple camera and a small computer, such as a Raspberry Pi. Combining this capability with data acquired using an infrared (IR) thermal camera it is possible to monitor an entire room with multiple regions of interest using a single device, which can be made mobile. In this task, the student will develop a small real time monitor system; will make use of computer vision (CV) and machine learning (ML) algorithms to identify regions of interest from images acquired with an optical camera (e.g. a bird, frozen food, the forehead of a person); will match it to the output image of a thermal camera; will measure the corresponding temperature and set an alarm if the temperature is out of the allowed range. The know-how which will be acquired by the student has also many applications in other areas of applied physics and biophysics, as for example, in the detection of features of interest in raw signals, track identification and reconstruction, categorization of event topologies or medical imaging.

Experiência : CCMC
Local : Coimbra
Supervisor(s) : Francisco Neves, Filipe Veloso
Email : neves@coimbra.lip.pt
Vagas : 3
Duração/Datas : July 2021

Testes do novo detetor de tempo de voo para experiência HADES.
O espectrómetro HADES instalado no GSI Darmstad (https://hades.gsi.de/) está a sofrer um upgrade que inclui um novo detetor de tempo de voo na região forward. O grupo de detetores RPC do LIP esta a construir este detetor baseado na tecnologia de câmaras de placas resistivas (RPC em ingles). Estes detetores caraterizam-se por uma elevada resolução temporal e uma alta eficiência de deteção. Os candidatos irão participar nos testes feitos no laboratório (nomeadamente testes de resolução temporal e eficiência com raios cósmicos) com os detetores que serão instalados no fim do ano na Alemanha.

Experiência : RPC
Local : Coimbra
Supervisor(s) : Alberto Blanco
Email : alberto@coimbra.lip.pt
Vagas : 3
Duração/Datas : Aproximadamente 1-2 meses, datas flexíveis

Development of a portable system for scintillation detection
Organic scintillators with novel polymeric substrates are being developed in collaboration with the Institute for Polymers and Composites of the Minho University towards the design of detectors for future collider experiments. Radiation hardness and large scintillation light output of the materials are two critical points to optimize since the combination of these factors determine the lifetime and applicability of the scintillators. This project will focus on the assembly and test of a compact and portable device to detect scintillation light from small samples of scintillators. It will consist of a light-tight box housing an ultraviolet light source, the support for the scintillator sample to test and a photodetector. Such an instrument is required for sample monitoring at the production line to pre-select scintillating polymeric blends. The assembly and test stage will be carried out at LIP is Laboratory of Optics and Scintillating Materials - LOMaC - using reference scintillator samples.

Experiência : ATLAS
Local : Lisboa
Supervisor(s) : Rute Pedro, João Gentil, Agostinho Gomes
Email : rute@lip.pt
Vagas : 2
Duração/Datas : July and 1 to 15 September

Estudo de um microdosimetro de fibras cintilante em diferentes ambientes de radiação utilizando o codigo FLUKA
A dosimetria de elevada resolução e a microdosimetria desempenham um papel fundamental na caracterização do campo de radiação em radioterapia com iões pesados. O conhecimento da energia depositada à escala sub-mm é essencial para reduzir as incertezas no alcance de protões e iões de carbono nos tecidos (na região do pico de Bragg). Pretende-se com este trabalho dar um contributo para o estudo da resposta óptica de fibras cintiladoras extremamente finas, que são a base de um microdosimentro actualmente em desenvolvimento no LIP. Este sera um trabalho de simulação utilizando o codigo FLUKA para preparação dos testes do microdosimetro em instalação de irradiação existentes em Portugal (IPO, Hospital Santa Maria, ICNAS etc.).

Experiência : RADART
Local : Lisboa
Supervisor(s) : Duarte Guerreiro, Jorge Sampaio, Joao Gentil
Email : jsampaio@lip.pt
Vagas : 1
Duração/Datas : 1 July - 15 September ( - 2 weeks in August)

High-precision timing detectors for HL-LHC
The group is developing high precision timing detectors based on LYSO crystals, silicon photomultipliers and dedicated ASIC electronics for the extended upgrade of the CMS experiment towards the future high-luminosity LHC (HL-LHC). The student will be involved in the experimental tests of the detectors for performance evaluation.

Experiência : CMS
Local : Lisboa
Supervisor(s) : Tahereh Niknejad
Email : tniknejad@lip.pt
Vagas : 1
Duração/Datas : July - August (to be agreed)

Investigating ANN and their use in the reconstruction of high energetic photons with the R3B calorimeter CALIFA
The Facility for Antiproton and Ion Research (FAIR) is an unique International Facility aiming to produce previously unobtainable reactive ion beams at unprecedented intensities and quality. The R3B setup – Reactions with radioactive ion beams – investigates nuclear structure, astrophysics and reactions. The newly developed versatile experimental setup was constructed to have high efficiency, acceptance and resolution for inverse- kinematic complete measurements. The dedicated CALIFA surrounds the target and can work as spectrometer, calorimeter or hybrid detector. One of the function is to detect photons up to 20 MeV. The focus of this work will be to investigate artificial neural networks to optimize advance gamma reconstruction algorithms. For this both simulations and actual real data are available.

Experiência : NUC-RIA
Local : Lisboa
Supervisor(s) : Daniel Galaviz, Pamela Teubig
Email : galaviz@lip.pt
Vagas : 1
Duração/Datas : Flexible dates: from July to September

Radiation at Mars with SRAM-based monitors
Radiation is one of the major hazards for manned and unmanned missions to Mars. Because the Mar’s atmosphere is much thinner than the Earth’s, Galactic Cosmic Rays (GCRs) and Solar Energetic Particles (SEPs), can reach the ground and damage biological and electronical systems. Scientific missions are expensive endeavors with limited mass and power for each instrument. For this reason, radiation monitors that are usually seen as housekeeping instruments are often overlooked. In fact, measurements of the Martian radiation environment have been made only by flybys of missions to the outer system, and by the Radiation Assessment Detector (RAD) on the Curiosity rover. While radiation effects on electronic components are a major concern for space missions, they also provide information about the environment that caused them. In the last decade, different technologies have been explored as an inexpensive way to monitor radiation. One of the most promising devices are SRAMs. Single Event Upsets, i.e., bit flips caused by energetic particles on these devices follow the same response of standard silicon telescope detectors used in Space missions. In this project, the student will study the sensitivity of the European Space Agency (ESA) SEU Monitor to study its sensitivity in interplanetary Space, Mars orbit, and Mars surface, and compare it to the measurements made in Geostationary orbit.

Experiência : SpaceRad
Local : Lisboa
Supervisor(s) : Marco Pinto, Luisa Arruda
Email : mpinto@lip.pt
Vagas : 2
Duração/Datas : June-August (negotiable)

Setting up a spectrometer to measure the absolute light yield of scintillating materials
Plastic scintillators are a fundamental sensitive material used in the construction of particle physics detectors. They are widely used at the LHC, namely on the hadronic barrel calorimeter of ATLAS (TileCal), and current understanding places this technology as a viable option for the construction of future detectors. However, the development of radiation-harder materials with larger scintillation efficiency will be fundamental to meet the challenging criteria of the design of new experiments. In this internship, the work will focus on measuring this efficiency by preparing a setup to measure the absolute light yield of scintillators, a fundamental characteristic of scintillating materials and also an indispensable parameter for their simulation. The aim of the internship will be to assemble and test the spectrometer system from nuclear instrumentation modules, which requires testing different combinations of hardware modules and photodetectors and defining the best arrangement for the setup. The tests will be made against measurements of the absolute light yield of reference scintillating fibres.

Experiência : LOMaC
Local : Lisboa
Supervisor(s) : Agostinho Gomes, Luis Gurriana, João Gentil Saraiva
Email : gentil@lip.pt
Vagas : 1
Duração/Datas : July-September (- 2 weeks in August)

Simulating the impact of proton therapy on amyloid protein structures using Geant4-DNA
Traditional radiotherapy (RT) is commonly associated with the treatment of cancer, however it also has successfully been implicated for the treatment of toxic protein aggregates of chronic degenerative disorders. Proton therapy could be a promising alternative for the treatment. However, it is unknown the impact of the use of proton beams on these toxic protein aggregates. Within this project, the student will use the particle transport simulation code GEANT4, combined with the specific Geant4-DNA toolkit, to assess the impact of proton irradiation on brain cells and amyloids.

Experiência : RADART
Local : Lisboa
Supervisor(s) : Pamela Teubig, Daniel Galaviz, Manuel Xarepe
Email : pteubig@lip.pt
Vagas : 2
Duração/Datas : Flexible, from July to September

Simulation of large scintillators for future HEP experiments using GEANT4
Calorimeters using plastic scintillators are showing an amazing performance in current running experiments as in the ATLAS tile calorimeter (TileCal) of the LHC. This type of technology is seen as a reliable option for future calorimeters for the next generation of high energy experiments at the Future Circular Collider (FCC). A big part of the work in the preparation of these huge detectors relies on simulations capable to show their real impact on physics and in particle physics we rely on codes like GEANT4. In these simulations, every single element of the detector are simulated and in this internship, we will follow up on the validation of the experimental setup used at LOMaC to characterize large scintillators. This needs to be fine-tuned and in particular, we need to investigate the differences seen in the scintillator response between simulation and experimental data. If time allows we will explore possible configurations for the coupling and assembly of these materials in calorimeters. The internship may work fully remote but visits to the laboratory to inspect the setup and the materials although not mandatory will be welcomed and probably inspirational. Having some basic knowledge of C++ will certainly be helpful (go faster) but not necessary or mandatory (go slower but also learn a lot on how a particle physics simulation is done).

Experiência : LOMaC
Local : Lisboa
Supervisor(s) : João Gentil Saraiva, Bernardo Tome, Ana Luísa Carvalho
Email : gentil@lip.pt
Vagas : 2
Duração/Datas : 1 July - 15 September ( - 2 weeks in August)

Sistema de alta tensão do Tilecal
A renovação do detector ATLAS para funcionar no LHC de alta luminosidade (HL-LHC) implica a substituição de toda a electrónica do calorímetro hadrónico Tilecal, incluindo o sistema de alta tensão (HV) que alimenta os cerca de 10000 fotomultiplicadores do Tilecal pois o sistema actual não suporta a radiação prevista para o HL-LHC. O novo sistema de alta tensão vai estar localizado fora do detector numa zona não exposta à radiação (caverna USA15), e consiste em cartas reguladoras e distribuidoras de alta tensão e cartas com conversores DC-DC de alta tensão que produzem a HV primária (HV supplies). Para levar a HV ao detector serão usados cabos de cerca de 100 metros de comprimento, e dentro do detector a HV será distribuída por cartas de distribuição Hvbus. O novo sistema de HV está a ser desenvolvido no LIP. Novos protótipos estão a ser desenhados e testados. Um protótipo da carta HV remote está em produção e será testada em conjunto com o protótipo da carta HV supplies. As cartas serão testadas no protótipo da crate ou com recurso a placas adaptadoras para a ligação entre elas, utilizando software específico desenvolvido para o respectivo controlo e monitorização. Neste estágio será avaliado o desempenho dos vários protótipos.

Experiência : ATLAS
Local : Lisboa
Supervisor(s) : Agostinho Gomes e Guiomar Evans
Email : agomes@lip.pt
Vagas : 1
Duração/Datas : Datas flexíveis a partir de Julho, duração de cerca de 1 mês

Telescópio de muões / Chuveiros atmosféricos - Laboratório de Raios Cósmicos (LabRC)
Os muões são partículas criadas na interação dos raios cósmicos com a atmosfera.No Laboratório de Raios Cósmicos existem detectores de cintilação capazes de detectar estas partículas. O sinal resultante da passagem do muão assim como o instante de tempo da sua passagem, são determinados com o auxílio de uma placa de aquisição de dados desenvolvida pelo laboratório de Fermilab (USA). O que se propõe neste trabalho é medir a taxa de muões com um detector telescópico, operacionalizando o detector e participando no desenvolvimento de um software de aquisição de dados, controlo e de monitorização dos resultados de física, usando a paralelização de processos em computação. (alunos 2º, 3º, 4º anos)

Experiência : AMS
Local : Lisboa
Supervisor(s) : Fernando Barão
Email : fernando.barao@tecnico.ulisboa.pt
Vagas : 2
Duração/Datas : 1-2 meses - Julho, Setembro (até ao início das aulas)

Thermal evaporation of thin layers of Copper for detector development
Resistive heating vacuum evaporation is a traditional tool used in the deposition of thin coatings on thicker surfaces, with thicknesses ranging from a few tenths of nanometers to few micrometers. The group is interested in the production of thin copper layers on glass slides, forming strips, with possible application in gaseous detector technology. The student will learn the basic principles of resistive heating vacuum evaporation, as well as working on the design of the mask needed for the creation of the strip pattern.

Experiência : NUC-RIA
Local : Lisboa
Supervisor(s) : Manuel Xarepe, Pamela Teubig
Email : mxarepe@lip.pt
Vagas : 1
Duração/Datas : Flexible dates. From July to September

Assessing the class of functions learnt by Deep Learning models on low-level jet data formats
Deep Learning models offer a very versatile approach to Machine Learning tasks as they can abstract high-level features from low-level formats. In the context of High-Energy Physics, this might represent the capacity to learn new observables that have not been considered or proposed so far. In this work we will study how different architectures can predict different known jet substructure variables.

Experiência : ATLAS
Local : Minho
Supervisor(s) : Nuno Castro, Miguel Romão, Rute Pedro
Email : mcromao@lip.pt
Vagas : 1
Duração/Datas : Jul-Ago

Física Experimental de Partículas com o detector ATLAS
A Física das Altas Energias estuda as propriedades das partículas elementares e as suas interacções. O Modelo Padrão da Física de Partículas (SM) descreve com uma precisão espantosa os dados experimentais obtidos até à data. No entanto, não fornece respostas para o número de famílias ou a hierarquia de massas das partículas elementares, a natureza dos neutrinos, a existência de matéria e energia escuras ou a unificação de todas as forças conhecidas. Vários modelos de física para além do SM propôem soluções para estes problemas, como por exemplo a Superssimetria ou as Dimensões Extra. A experiência ATLAS do CERN, o laboratório europeu para a física de partículas localizado em Genebra, na Suiça, foi desenvolvido para fornecer respostas a vários destes problemas. O quark top é a partícula elementar mais pesada que se conhece e é um excelente objecto para testar o SM. Desvios das previsões do SM relativas às propriedades da produção e decaimento do quark top no detector ATLAS fornecem testes independentes de modelos específicos para nova física, com fortes implicações para o SM. Por outro lado, o bosão de Higgs é uma das peças fundamentais do SM, pois é parte integrante do mecanismo de atribuição de massa às partículas elementares. A sua existência foi proposta em 1964 e foram necessários quase 50 anos para o descobrir. Neste estágio serão analisados dados da experiência ATLAS.

Experiência : ATLAS
Local : Coimbra
Supervisor(s) : Filipe Veloso, Ricardo Gonçalo
Email : filipe.veloso@cern.ch
Vagas : 3
Duração/Datas : Julho 2021

Advanced Machine Learnnig for Exclusive Processes
Nowadays, the world of High Energy Physics is deeply involved in machine learnings (ML) techniques. With ML we mean algorithms whose aim is “teaching” to the calculator how to recognise hidden patterns. The way we design these algorithms is not so different from the way we teach to children. To make an example, think to have in front of you 100 bottles; the majority of them is made of plastic while some of them is made of glass. You want to teach to a children to recognise the ones made of glass. You can do that showing the children several bottles of glass and then several bottles of plastic, showing what are the differences. After this “training session” one may leave him/her alone and he/she will start working. At the end of the work, one can judge his/her work, quoting his efficiency. In high energy physics, we do exactly the same: we take a sample of signal events (the ones we want to save in our analysis) and a sample of background events (that we want to reject). We show to the computer, one by one, the signal events and then the background ones. At the end of this process we mix the samples and we evaluate the efficiency of the computer to separate them. The student will be asked to develop his/her own ML algorithm which will be then tested on true high energy physics samples. In particular, at LIP we are interested in studying central exclusive events. In these events, two incoming protons interact without dissociating. As a result, the final state contains a pair of undissociated protons together with the recoiling particles produced in the interaction. These extra particles are produced with an energy corresponding to that lost by the incoming protons. The candidate will study these processes and determine the possible presence of a new resonant contribution. A dedicated study of boosted objects with the specific goal of improving the identification of high-mass resonances and the sensitivity to New Physics processes may be developed.

Experiência : CMS
Local : Lisboa
Supervisor(s) : Matteo Pisano, Michele Gallinaro, Jonathan Hollar
Email : matteo.pisano@cern.ch
Vagas : 2
Duração/Datas : June-August (flexible)

ATLAS Liverpool Protocol
Reserved to Liverpool University

Experiência : ATLAS
Local : Lisboa
Supervisor(s) : Patricia Conde
Email : pconde@lip.pt
Vagas : 3
Duração/Datas :

Deep Neural Networks applications in experimental physics data analysis
One of the focus of the Heavy Ion program of the LHC in Run 3 is the study of heavy flavour jets (collimated sprays of particles originating in the hadronization of charm and bottom quarks). Deep Neural Networks to tag these jets in the demanding Pb+Pb collisions environment are under development. The student will collaborate to these efforts by implementing an hyper parameter scanner with the goal of optimising the DNN.

Experiência : ATLAS
Local : Lisboa
Supervisor(s) : Helena Santos
Email : helena@lip.pt
Vagas : 1
Duração/Datas : 4 weeks, July

Evaluating new methods for identifying Higgs boson decays into a pair of b- quarks at high transverse momentum
The precise measurement of the Higgs boson properties continues to be on the high priority list of the ATLAS and CMS Physics programme. It will not only help to determine the precision up to which the Standard Model of Particle Physics (SM) is valid, but will also help to search for new physics in case deviations from the SM predictions are found. Measuring the rate of production of Higgs bosons at high momentum is particularly interesting, since it is the most sensitive regime to beyond SM effects. This project targets the decay of the Higgs boson to a pair of b-quarks, in the WH production channel. Simulations of WH(bb) production and its main background processes will be used and recent developments in Higgs to bb tagging will be explored, with the goal of pinpointing main sources of background and identifying future avenues for improvement.

Experiência : ATLAS
Local : Lisboa
Supervisor(s) : Inês Ochoa, Patricia Conde
Email : pconde@lip.pt
Vagas : 1
Duração/Datas : 12-30th July, 23rd August- 5th September.

Investigating the Flavor Anomalies
The recent "Flavor Anomalies" form the strongest evidence for new physics (NP) at colliders. These are revealed in quark-level transitions, such as b-> s, a process that is disfavored in the standard model (SM) but can more readily occur in NP scenarios (for example, involving new gauge or higgs bosons or even stranger new particles known as leptoquarks). The search and study of such rare decays are extremely powerful analyses to probe physics beyond the SM. These so-called indirect searches, performed at particle colliders like the Large Hadron Collider (LHC), offer sensitivity to the presence of NP at energy scales much larger than the actual energy of the collisions. The rare decays of B hadrons are particularly interesting processes to study: their decay rate being highly suppressed in the SM, they are sensitive up to very small interferences from NP effects. The decay of the B0 meson into K*0 mu+ mu- is in particular an ideal candidate for these studies: the decay rate is doubly suppressed in the SM (occurring only via quantum mechanical loops), and an analysis of the angular distribution of the produced particles and of the decay rates allow to measure several parameters sensitive to different NP sources, while experimentally the presence of two muons also facilitates the identification of this decay in busy collision events. The interest in this decay channel has been raised when several measurements performed by the LHC experiments (LHCb, CMS, ATLAS) and elsewhere showed evidence of discrepancies from the SM predictions that, if confirmed, point to the presence of NP. The Compact Muon Solenoid collaboration (CMS) with the analysis with the data collected in 2012 showed to be able to produce a measurement of these parameters among the most precise ever performed. We are currently analyzing the large amount of data collected in 2016, 2017 and 2018 with the goal of producing a very precise measurement, to confirm the discrepancy or prove it wrong. In this project you will work with data collected by the CMS experiment during these three years. You will analyze the spectrum of the B0 meson mass and decay angle distributions, exploring means for describing the spectra observed in the data, separating signal from background, and using statistical procedures for characterizing and measuring the signal properties. The work has the potential for significantly contributing to the CMS-wide exploration of the tantalizing Flavor Anomalies.

Experiência : CMS
Local : Lisboa
Supervisor(s) : Alessio Boletti, Maria Faria, Nuno Leonardo
Email : nuno.leonardo@cern.ch
Vagas : 1
Duração/Datas : July - September (flexible)

Machine Learning Methods to measure the quantum numbers of the Higgs interaction to W bosons
Since the discovery of the Higgs boson, the precise measurement of its properties has become a fundamental part of the ATLAS Physics programme. The Portuguese ATLAS team has contributed to many Higgs measurements, including the first observation of the Higgs decays to b-quarks, the observation of the associated production of a Higgs and a vector boson, and the measurement of boosted H->bb decays. As the LHC continues to take data and more luminosity is accumulated, more precise measurements are possible, opening the door to search for new physics in the Higgs sector. In this project, the student(s) will join the LIP ATLAS team to participate in the studies of the Higgs couplings. The Spin/CP properties of the interaction between the Higgs boson and W boson pairs affect the distributions of the final state particles in the associated production channel of the Higgs with a W boson, pp →WH → l nu bb. New very promising methods that use Machine Learning techniques, have been recently proposed and are currently the focus of the Portuguese ATLAS team. The student will contribute to the optimisation of this methods in order to improve the separation of different spin/CP observables.

Experiência : ATLAS
Local : Lisboa
Supervisor(s) : Inês Ochoa, Ricardo Barrué, Patricia Conde
Email : pconde@lip.pt
Vagas : 1
Duração/Datas : 12-07-2021 to 31-07-2021, 16-08-2021 to 9-09-2021

Muon efficiency performance with Tag and Probe using CMS Open Data
The tag & probe method (T&P), successfully used formerly also at the Tevatron collider, relies upon Z → di-lepton decays to provide an unbiased, high-purity lepton (electron or muon) sample with which to measure the efficiency of a particular selection. In this work, an LHC dataset collected by CMS with a single-lepton trigger is used to obtain a sample of di-lepton events. The efficiency of the CMS muon identification algorithms will be studied with T&P: the tag is a well-identified muon triggered in the event, while the probe is an additional track that when combined with the tag yields a mass compatible with that of the J/ψ, Upsilon or Z resonances. The efficiency is obtained by fitting the tag+probe invariant mass distributions, simultaneously for both when the probes pass and fail the selection criteria. For accessing higher muon momenta (20 < pT < 300 GeV), the Z resonance will be employed. In this project, we will determine the CMS detector performance for identifying muons, using several trigger paths. The developed tools may be integrated in the toolkit for Open Data analysis, and a comparison with CMS official performance will be delivered.

Experiência : CMS
Local : Lisboa
Supervisor(s) : Sandro Fonseca, Eliza Melo, Allan Jales, Nuno Leonardo
Email : sandro.fonseca@cern.ch
Vagas : 2
Duração/Datas : July-September (flexible)

Search for dark matter in association with a new Z` boson at the LHC
One of the most unsolved problems in particle physics is the existence of dark matter (DM), which is a new type of non-luminous and non-baryonic matter. The astrophysical observations proposed the existence of DM to modulate the masses of the galaxies. It has been found from astrophysical observations that DM contributes to about 27% of the mass of the Universe. In parallel to the evidence from astrophysical observations, search for DM at the Large Hadron Collider (LHC) is ongoing. Signature of DM at the LHC will be in the form of missing energy, since it is very weakly interacting with ordinary matter [1]. On the other hand, the standard model (SM) of particle physics is successful in the unification between the electromagnetic force and the weak nuclear force in a single force described by the electroweak theory that predicted the existence of W+,W- and Z bosons. However, the SM fails to unify the four fundamental universal fields (electromagnetic, weak, strong and gravity fields) [2]. In grand unification theories, it is possible to unify the electroweak force and the strong force in a single interaction predicting new heavy bosons (MGU << MSM ) such as the Z`. The lifetime of the Z` is very short such that it decays rapidly to either di-lepton or di-neutrino pairs, or to a pair of quark–antiquark [3][4]. One of the interesting models based on the grand unification is known as Mono-Z` model, which proposes the production of DM particles in association to a Z` boson. This process can be produced at the LHC via quark-antiquark annihilation. Work plan: 1. Perform MC simulation for Mono-Z` model signal at several mass points of Z` for the di-lepton decay channel; 2. Perform the simulation and estimate the expected backgrounds; 3. Analyze the signal samples, compare with expectations and interpret the results. References: [1] K. Arun, S.B. Gudennavar and C. Sivaram, ``Dark matter, dark energy, and alternate models: A review,`` Adv. Space Res. 60 (2017) 166, arXiv:1704.06155 [physics.gen-ph] [2] D. H. Perkins, "Introduction to high energy physics" [3] D. Hayden, R. Brock and C. Willis, ``Z Prime: A Story,`` [arXiv:1308.5874 [hep-ex]]. [4] N. Pollard, ``B-L and Other U(1) Extensions of the Standard Model,`` PhD thesis, University of California, Riverside (2017) [5] M. Autran, K. Bauer, T. Lin and D. Whiteson, ``Searches for dark matter in events with a resonance and missing transverse energy,`` Phys. Rev. D 92 (2015) 035007, arXiv:1504.01386 [hep-ph]

Experiência : CMS
Local : Lisboa
Supervisor(s) : Sherif Elgammal, Michele Gallinaro
Email : michgall@cern.ch
Vagas : 2
Duração/Datas : June-July/August (flexible)

Searching for new physics by colliding light in the CMS experiment at the LHC
In a small fraction of events at the LHC, photons can collide with extremely high energies, providing a way to study new Beyond Standard Model effects that are otherwise very difficult to detect in colliders. The CMS experiment uses a set of small forward detectors, the Precision Proton Spectrometer, to identify and reconstruct these events. Recently CMS has released the first results from an analysis of very high energy "light-by-light" scattering using these detectors. In this project, the student will analyze simulated LHC light-by-light scattering collisions, to obtain the predictions of different models of new physics. Then, they will compare to the real CMS public data, to test if it agrees with the predictions or not.

Experiência : CMS
Local : Lisboa
Supervisor(s) : Jonathan Hollar, Matteo Pisano, Michele Gallinaro
Email : jjhollar@cern.ch
Vagas : 1
Duração/Datas : Starting June/July (negotiable)

Understanding hadronization timescales using jets
Jets are algorithmic proxies of hard scattered partons, i.e. quarks/gluons, in high energy collisions. Current jet measurements use algorithms that cluster objects, either particles from an event generator or charged tracks/calorimeter towers in experiments, iteratively depending on the distance between objects and a momentum threshold. These clustering algorithms contain additional information regarding the jet shower that has been exploited in vacuum (proton-proton collisions) via the SoftDrop algorithm to provide a handle on the jet shower via its splittings. To further explore jet sub-structure, the student will use these observables recursively through the jet shower history, providing thus stringent constraints on model parameters related to the shower and non-perturbative effects such as hadronization. The output will serve as a first step towards identifying and tagging jets based on their shower characteristics.

Experiência : Pheno
Local : Lisboa
Supervisor(s) : Liliana Apolinário
Email : liliana@lip.pt
Vagas : 2
Duração/Datas : July, August

Deteção de anomalias como ferramenta para descoberta de nova física no Large Hadron Collider do CERN
Este projeto irá permitir estudar o uso de técnicas de machine learning num contexto de aplicação a dados reais (ATLAS OpenData), contribuindo para melhorar a sensibilidade de pesquisas genéricas em desenvolvimento, bem como para melhor entender o impacto de sistemáticos dos métodos de deteção de anomalia quando aplicados a dados reais. Dará também um contributo para a resolução de problemas de análise de dados e deep learning que surgem neste contexto. Permitirá ao estudante aprofundar o seu conhecimento de física de partículas e adquirir competências em técnicas avançadas de análise de dados.

Experiência : SimBigDat
Local : Minho
Supervisor(s) : Nuno Castro, Miguel Romão
Email : nfcastro@lip.pt
Vagas : 1
Duração/Datas : To be agreed (May-July)

Detecção de anomalias como teste de novos fenómenos de física nos dados da experiência ATLAS do CERN
Este projeto irá permitir estudar o uso de técnicas de machine learning num contexto específico de Física de Partículas (pesquisa genérica por sinais de nova física em colisões hadrónicas), contribuindo para alargar a sensibilidade das pesquisas em curso a outros sinais. Dará também um contributo para a resolução de problemas de análise de dados e deep learning que surgem neste contexto. Permitirá ao estudante aprofundar o seu conhecimento de física de partículas e adquirir competências em técnicas avançadas de análise de dados.

Experiência : ATLAS
Local : Minho
Supervisor(s) : Nuno Castro, Rute Pedro
Email : nfcastro@lip.pt
Vagas : 1
Duração/Datas : To be agreed (May-July)

Transferability in machine learning: LHC searches as a case study
The transferability of deep neural networks in the context of searches for different new physics signals at the LHC will be explored in this project. Different approaches, such as meta learning, will be studied.

Experiência : SimBigDat
Local : Minho
Supervisor(s) : Nuno Castro, Miguel Romão
Email : nfcastro@lip.pt
Vagas : 1
Duração/Datas : To be agreed (May-July)

Using the HiggsML dataset to benchmark machine learning techniques
The ATLAS open data provide several analysis to be performed on proton-proton LHC data collected at a center of mass of 13 TeV. In this project such dataset will be explored and advanced machine learning techniques will be tested using real ATLAS data and detailed Monte Carlo simulation.

Experiência : ATLAS
Local : Minho
Supervisor(s) : Nuno Castro, Miguel Romão
Email : nfcastro@lip.pt
Vagas : 1
Duração/Datas : To be agreed (May-July)

De que são feitos os nucleões e os piões?
Toda a matéria que conhecemos é composta por partículas elementares, sem estrutura interna, tais como quarks e electrões. Ao agrupar os quarks, segundo alguns critérios, emergem partículas mais complexas, os hadrões, dos quais fazem parte os nucleões (protões e neutrões) e os piões. COMPASS e AMBER são duas experiências de alvo fixo no CERN, que têm como um dos seus principais objetivos o estudo da estrutura interna desses hadrões. Para isso são usados feixes de piões que ao embater em alvos de nucleões permitem aprender mais sobre ambos. A análise do processo raro conhecido como Drell-Yan serve de base para desvendar a composição dos hadrões e as suas características. A experiência COMPASS opera desde 2002 e é responsável por importantes resultados em Cromodinâmica Quântica (QCD). A experiência AMBER, que sucede a COMPASS, foi aprovada em 2020 e começará a tomar dados nos próximos anos, encontrando-se em fase de preparação. Assim, este estágio beneficia da dualidade de podermos analisar dados reais tomados recentemente por COMPASS ou dados de simulação que servem de suporte a AMBER. O objetivo do estágio é perceber como é que um físico de partículas trabalha no seu dia a dia para aprender mais sobre as características dos hadrões.

Experiência : P&QCD
Local : Lisboa
Supervisor(s) : Márcia Quaresma, Catarina Quintans
Email : marcia@lip.pt
Vagas : 2
Duração/Datas : cerca de 1 mês (datas flexíveis)

Exploring jet quenching effects during QGP initialisation
Ultra-relativistic heavy-ion collisions allow to reach extreme temperature and density conditions, thus creating a new state of matter called the Quark-Gluon Plasma. In a timescale below one yoctosecond, quarks and gluons - the fundamental degrees of Quantum Chromodynamics (QCD) - initially confined inside hadrons are now asymptotically free. The consequence is a medium that behaves as the most perfect fluid ever created in Nature. How such collectivity arises from the fundamental principles of interaction between QCD degrees of freedom is among the most pressing unknowns of this sector of the Standard Model of Particle Physics. In this project, the student(s) will investigate how jets - a spray of collimated particles produced by a high energy quark or gluon during the initial collision - can help to constrain the uncertainties during the QGP initialisation phase.

Experiência : Pheno
Local : Lisboa
Supervisor(s) : Liliana Apolinário, Ruben Conceição
Email : liliana@lip.pt
Vagas : 2
Duração/Datas : July, August

Heavy quarks as probes of the primordial plasma
At the LHC, we recreate droplets of the primordial medium that permeated the universe microseconds after the big bang. Heavy-flavor particles are highly sensitive “hard probes” of the properties of this hot and dense soup of quarks and gluons (the quark-gluon plasma, QGP). The decays of these heavy particles are being reconstructed for the first time ever in such a challenging and busy collision environment by the CMS experiment at the LHC. The goal of this project is to reconstruct B0 mesons for the first time in nuclear collisions, and use b-quark mesons produced in lead and proton collisions to study critical properties of the QGP. This will be achieved by exploring PbPb and pp datasets collected by the CMS experiment in the most recent LHC run. The exploration of these meson signals will provide unique information about the underlying properties of the QGP medium.

Experiência : CMS
Local : Lisboa
Supervisor(s) : Maria Faria, Nuno Leonardo
Email : nuno.leonardo@cern.ch
Vagas : 2
Duração/Datas : June - September (flexible)

Hunting for Kaons with Neural Networks
AMBER is a future experiment at CERN which will try to answer the question: where does the mass of the proton come from? (Famous Higgs boson interaction is only responsible for 1% of the proton mass) In one of the planned measurements a kaon beam (strange meson) will interact with a proton target producing two muons, the so-called Drell-Yan process. However, in the available negative beam only 3% of the particles are kaons, the rest being mostly pions. The particle species can be identified by detectors called CEDARs, but the very high intensity of the beam makes its operation challenging. The idea of this internship is to use the available data of the COMPASS experiment, together with new analysis methods, mostly Neural Networks, to verify if the COMPASS CEDAR detectors can be used for this purpose, or if a new detector has to be designed and built. The student will use the Neural Networks Keras framework (python based) to analyze the COMPASS CEDAR data taken in 2018.

Experiência : P&QCD
Local : Lisboa
Supervisor(s) : Marcin Stolarski, Marcia Quaresma
Email : mstolars@lip.pt
Vagas : 2
Duração/Datas : to be agreed with students (time 3-6 weeks)

Novel jet algorithms to unveil the Quark-Gluon Plasma evolution
The Quark-Gluon Plasma (QGP) is thought to be the primordial state of matter which filled the universe immediately after the Big Bang. Consisting of a collection of quarks and gluons in a deconfined state, this medium is the perfect laboratory to extend our knowledge frontier of the theory of the strong interactions (QCD), one of the building blocks of the Standard Model of Particle Physics. Its study is currently being pursued at the LHC (CERN) and RHIC (BNL), where the QGP can be recreated in ultra-relativistic heavy-ion collisions; however, how it evolves from a hot and dense fireball to a final state hadronic event is still largely unknown. Jets - a spray of collimated particles resulting from a high momentum quark or gluon - encode a succession of emissions that transform a single particle into a multi-particle system. While in proton-proton collisions this process can be described by a multitude of prescriptions, the presence of a QGP can, for the first time, be used to explore the quantum mechanical nature of a QCD emission and its succession pattern. Simultaneously, the differential analysis of this fragmentation pattern can unveil the QGP characteristics at different evolution stages. Recent results showed that the QGP time evolution provides the best ordering variable to describe QCD jets in heavy-ion collisions. The selected student(s) will use the developed jet algorithm prescription to identify the timescales that can be mapped from jets to the QGP and will use this map to constrain current QGP time evolution models.

Experiência : Pheno
Local : Lisboa
Supervisor(s) : Liliana Apolinário, André Cordeiro, Guilherme Milhano
Email : liliana@lip.pt
Vagas : 3
Duração/Datas : July, August

QCD effects in the muon anomalous magnetic moment
The anomalous magnetic moment of the muon (“muon g-2”) is a hot topic in particle physics and has very recently attracted attention due to new measurements at Fermilab. The muon acts like a spinning magnet and has a magnetic moment or “g factor”, whose deviation from 2 is the anomalous part and due to quantum effects. The muon g-2 picks up contributions from all parts of the Standard Model - electromagnetic, weak and strong interactions - and there is a persistent discrepancy between the Standard Model prediction and the experimental measurements which may point towards new physics. The biggest uncertainties in the theoretical prediction come from Quantum Chromodynamics (QCD), which describes the interactions between quarks and gluons. QCD encodes fundamental nonperturbative properties of the strong interaction that are still not well understood: the origin of confinement of quarks in hadrons and nuclei, the origin of mass, the structure of exotic hadrons such as tetraquarks and pentaquarks, and the properties of matter in extreme conditions such as heavy-ion collisions and neutron stars. In this project we will compute the largest QCD contribution to the muon g-2 to test the Standard Model predictions.

Experiência : NPStrong
Local : Lisboa
Supervisor(s) : Gernot Eichmann
Email : gernot.eichmann@tecnico.ulisboa.pt
Vagas : 2
Duração/Datas : July, August

The analytic structure of quarks
The strong interaction between quarks and gluons is described by Quantum Chromodynamics (QCD), which encodes fundamental nonperturbative properties that are still not well understood: the origin of confinement of quarks in hadrons and nuclei, the origin of mass, the structure of exotic hadrons such as tetraquarks and pentaquarks, and the properties of matter in extreme conditions such as heavy-ion collisions and neutron stars. One of the biggest open questions in hadron and nuclear physics is the nature of confinement: quarks and gluons carry ‘color’ and they are not observable due to color confinement, i.e., we cannot observe free quarks and gluons but only their bound states which are hadrons. Confinement manifests itself in the basic properties of quarks and gluons as functions of the momentum scale, namely their singularity structure in the complex momentum plane. In this project we will investigate these properties to gain basic insight on the analytic structure of quarks.

Experiência : NPStrong
Local : Lisboa
Supervisor(s) : Gernot Eichmann
Email : gernot.eichmann@tecnico.ulisboa.pt
Vagas : 1
Duração/Datas : July, August