HEИндивидуална стипендия2023–2026

4TopAndMore · Probing new physics with four top quarks

„Хоризонт Европа“ — Действия „Мария Склодовска-Кюри“

Период: 2023-10-16 → 2026-03-15
Финансиране от ЕС: 181 153 €
Участници: 1
Схема: HORIZON-TMA-MSCA-PF-EF

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Накратко на български

Производството на четири топ кварка се анализира чрез данни от Големия адронен колайдер, за да се открият нови частици или взаимодействия. Това помага да се разберат пропуските в Стандартния модел, като например природата на тъмната материя.

Този кратък обзор е генериран от изкуствен интелект

Кратко обяснение, генерирано от езиков модел по текста на CORDIS. Оригиналът е по-долу.

Резултати накратко

Probing new physics with four top quarks

The Standard Model of particle physics is an extremely successful description of known fundamental particles and interactions, but it remains incomplete. It does not explain, for example, the origin of the Higgs-boson mass scale, the nature of dark matter, or the observed matter–antimatter asymmetry of the universe. Many theories beyond the Standard Model predict new particles or interactions, referred to as new physics, that couple strongly to the top quark, the heaviest known elementary particle. Processes involving several top quarks are therefore especially powerful probes of new physics. This project focused on the production of four top quarks, tttt, using data collected by the ATLAS experiment at the Large Hadron Collider (LHC). Four-top-quark production is one of the rarest and most energetic processes accessible at the LHC. It can reveal new physics in several ways: through a production rate larger than predicted, through altered event kinematics, through new heavy particles that decay into top quarks, or through indirect effects described by effective field theories. The original objective of the project was to use tttt production to search for new physics through three connected steps: discovery and inclusive cross-section measurement, differential measurements of kinematic distributions, and interpretation of the results in terms of possible new physics. The project also planned to develop improved reconstruction tools for complex multi-top-quark events. During the fellowship, the scientific context changed significantly. Four-top-quark production was discovered before the start of the project in a previous analysis led by the researcher using LHC Run 2 data. The project was therefore re-focused towards the next scientific step: using the established tttt process as a platform for dedicated new-physics searches and preparing the analysis tools needed for LHC Run 3 data at the new energy frontier of 13.6 TeV. The project pathway to impact was therefore to improve the experimental and methodological foundations for future tttt measurements and searches. This included preparing Run 3 analysis infrastructure, improving object selection and electron calibration, implementing improved simulations for rare backgrounds, developing machine-learning tools, contributing to new-physics searches, and producing sensitivity projections for the High-Luminosity LHC (HL-LHC). These activities contribute to the long-term European strategy for particle physics by clarifying what future LHC and HL-LHC data can reveal about the fundamental structure of matter.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз

Цел на проекта

At the Large Hadron Collider (LHC), protons are collided at the highest possible energy to generate subatomic elementary particles. We use the results of these collisions to understand our universe at the most fundamental level. Many theorists believe that new physics exists at a very high energy. The top quark is the heaviest elementary particle known to date with unique properties. It is therefore naturally suspected to have hidden connections with new physics.The simultaneous production of four top-quarks (tttt) is the most energetic process accessible with the LHC, making it a unique place to search for heavy new physics, which are less likely to appear elsewhere. The first evidence of these extremely rare events was only revealed last year, and we know very little about them. With the world-record energy at LHC Run3 (13.6 TeV), we expect 20% higher tttt events production rate. This offers a timely opportunity to further study this process.With an aim to find new physics, we will study tttt events in unprecedented detail with the ATLAS experiment at the LHC. We will measure the inclusive production rate and the kinematic properties of these events. We will use the measured results to probe new physics, with unique approaches that do not rely on new physics predictions made upon specific assumptions (which could be wrong). The results have the potential to reveal new physics that are too energetic and beyond the reach of the LHC. This will be the first time this is done for tttt events. The measured tttt event kinematics will be corrected to remove effects from the detector resolution and acceptance. This allows theorists to directly test their new physics predictions against the experimental results, continuously generating impact in the relevant scientific community. We will combine the results of tttt events with those of other types of events containing top quarks to build a global picture of the top quark in terms of its subtle connections to new physics.

Оригинален текст от CORDIS (на английски).

Участници

INSTITUTO DE FISICA DE ALTAS ENERGIAS · Cerdanyola Del VallesКоординаторИспания