Charged particle tracking applied to a search for dark matter in collider experiments
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Data
2022-03-14
Autores
Böger, João Paulo de Souza
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Universidade Estadual Paulista (Unesp)
Resumo
O seguinte projeto apresenta um estudo sobre a reconstrução de traços de partículas carregadas no detector de partículas CMS, localizado no LHC, e a viabilidade de detecção de partículas de matéria escura nesse. Nosso trabalho utiliza o modelo de Partículas Massivas de Interação Tênue (FIMPs), em que uma Partícula de Longa Vida (LLP), F, é predita e se acopla tenuemente a uma partícula carregada do Modelo Padrão (SM) e uma de Matéria Escura s: F −> s + SM. A partícula F decai no volume do CMS deixando uma assinatura de traço evanescente, isto é, o traço possui hits apenas das primeiras camadas do detector, dado que após F decair os produtos do decaimento não possuem energia suficiente, ou sequer interagem, com os elementos do detector. Um algoritmo de reconstrução de traços baseado na técnica de Kalman Filter Combinatório foi implementado em um detector simplificado, reconstruindo 40% dos traços de píons (pi ±) corretamente. Em seguida, uma análise de eventos contendo charginos (chi ±) como as partículas F do modelo de FIMP, gerados por simulações de Monte Carlo, foi realizada atingindo desempenho de 70% dos traços sendo reconstruídos apropriadamente, sugerindo que assinaturas de traços evanescentes podem ser detectadas no experimento CMS. Os resultados foram comparados e validados com uma análise da colaboração CMS.
This project presents the results of a study concerning charged particles tracking in the Compact Muon Solenoid (CMS) of the Large Hadron Collider (LHC) and the feasibility of detection of Dark Matter particles in the experiment. The work considers the Feebly Interacting Massive Particles (FIMPs) model, in which a charged Long-Lived Particle (LLP), F, is predicted to have tiny couplings with a charged Standard Model (SM) particle and a DM particle s: F −> s + SM. F is a LLP that decays within the CMS’ volume, generating a disappearing track signature, a track with hits in the first layers only and no signals in the further subdetectors of CMS, since the decaying products are either too soft or do not interact the detector’s material. A Combinatorial Kalman Filter (CKF) tracking reconstruction algorithm was developed within a toy model detector in this work, reconstructing 40% of pion (pi ±) tracks properly. Then, an analysis of Monte Carlo simulated events containing charginos (chi ±) as F particles - in the FIMP framework - was performed, reaching 70% of such particles’ tracks properly reconstructed, pointing in the direction that disappearing tracks’ signatures may be able to be detected in the CMS Experiment. Results were compared and validated with a CMS’ tracking performance analysis.
This project presents the results of a study concerning charged particles tracking in the Compact Muon Solenoid (CMS) of the Large Hadron Collider (LHC) and the feasibility of detection of Dark Matter particles in the experiment. The work considers the Feebly Interacting Massive Particles (FIMPs) model, in which a charged Long-Lived Particle (LLP), F, is predicted to have tiny couplings with a charged Standard Model (SM) particle and a DM particle s: F −> s + SM. F is a LLP that decays within the CMS’ volume, generating a disappearing track signature, a track with hits in the first layers only and no signals in the further subdetectors of CMS, since the decaying products are either too soft or do not interact the detector’s material. A Combinatorial Kalman Filter (CKF) tracking reconstruction algorithm was developed within a toy model detector in this work, reconstructing 40% of pion (pi ±) tracks properly. Then, an analysis of Monte Carlo simulated events containing charginos (chi ±) as F particles - in the FIMP framework - was performed, reaching 70% of such particles’ tracks properly reconstructed, pointing in the direction that disappearing tracks’ signatures may be able to be detected in the CMS Experiment. Results were compared and validated with a CMS’ tracking performance analysis.
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Palavras-chave
Detecção de traços de partículas, Matéria escura, Física experimental de altas energias, Física além do modelo padrão, Aceleradores de partículas