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Description
This project is focused on full exploration of the opportunities that will be provided by the collider experiments in the forseeable future, with the upgrades of the LHC. Its goal is to attack the questions relevant for the very early history of the universe. It will result in improved methods of the data analysis and of their presentation, based on the guiding by a broad spectrum of the existing and new theoretical models, analyzed from a new angle of documenting the similarities and differences in their experimental signatures. On several instances new data analysis techniques and new theoretical constructions will be investigated. Furthermore, theoretical interpretation of the potential new discoveries will be studied. This programme requires close collaboration between experimentalists and theorists. Our tasks, motivated by the goal of understanding the early universe are: 1) Machine learning assisted monojet analysis in search for dark matter and new electrically neutral stable particles and theoretical interpretation of the future data. 2) Discriminating theories by joint monojets and mono-higgs boson analyses. 3) Constraining the mechanism of the Electroweak Phase Transition by di-higgs boson production. 4) Probing new sources of CP violation in the Higgs-fermion sector. 5) Investigating the sphaleron and mini-black hole production at the LHC and its dependence on the mechanism of the EW phase transition. The proposed collaboration is meant not to interfere with the Bergen group participation in the ATLAS collaboration. Realistic but not proprietary simulations of experimental capabilities will be used. We see our collaboration as focused on searching for not yet fully explored signatures and the methods of analyses, as well as new ways of presenting their results, inspired by the Warsaw theorists proposals.
Summary of project results
There are two well known and highly publicized points about the present state-of-the-art in the physics of elementary interactions. One is the great success of the Standard Model, completed by the discovery of the Higgs-like particle, and its implications for the cosmological history of the Universe, starting with few parts in a million of a second after the Big Bang, confirmed by many astrophysical observations. The other is the fact that, nevertheless, the SM leaves several fundamental puzzles unexplained, in particular in the history of the very Early Universe. Moreover the theoretical structure of the SM itself, strongly points to the existence of a deeper theory.
In this project we focused on few experimental signatures that are generic for a broad spectrum of new physics models and, in fact, even for new phenomena with no concrete theoretical frameworks proposed yet. The guiding principle for our choice of signatures are the existing experimental/observational puzzles that SM is not able to explain, that is existence of Dark Matter, need for additional source of CP violation to explain the observed matter-anti matter asymmetry and, considering the electroweak baryogenesis to be
an interesting option, the characteristic of the EW phase transition. Our goal was to develop best strategies for observing such signatures in the experiments with the upgrades of the LHC, based on the guiding by a broad spectrum of the existing and new theoretical models. New data analysis techniques (Machine Learning) and new theoretical constructions was investigated. Furthermore, theoretical interpretation of the potential new discoveries was studied.
Most important project achievements.
- Search for supersymmetric particles (new limits and new signatures)
- New results on the origin of Dark Matter(supersymmetric and non-supersymmetric) and search for it
- New results on CP violation and BSM physics in Yukawa couplings-
- Development of Machine Learning Techniques and its application to the sphaleron and microscopic black holes production
- New results on electroweak phase transitions( with a Higgs particle as a pseudo- Nambu-Goldstone boson, with vector-like fermions)
- Search for long-lived particles with displaced vertices
- New theoretical tools for Effective Field Theories-related to all tasks of this project
- Developing tau lepton reconstruction methods necessary to control tau lepton background in many processes
The results of the project, in particular those linking the theoretical investigations with their experimental implementations are very important. Here one could mention a) the search for new physics effects in the Higgs decays (in particular for CP violation) and the developing of the tau reconstruction techniques, b)developments of Machine Learning techniques and analyses of complex, multiparticle final states, c) searches for Dark Matter and for supersymmetric particles that combine theoretical insight with new experimental methods.
Summary of bilateral results
Bilateral collaboration was satisfactory and documented by publications. Four papers have common co-authors from Warsaw and Bergen. This number is also the same that the target value of common papers. Moreover, a joint ERC grant was submitted.