10h : Léo Constantin (Physique Théorique)
10h30 : Louise Millot (ALICE)
10h : Léo Constantin (Physique Théorique)
"Tools and methods to investigate new physics"
Presentation in English
Abstract :
At LHC, no clear evidence of new physics has yet emerged. Despite the efforts made, there remains room for improvement in the methods we use to probe physics beyond the standard model (BSM).
I present strategies in the context of both direct and indirect searches to constrain supersymmetry.
First we study how well the public reinterpretation software SModelS v3.0 , which re-use direct searches results, compare with an internal reinterpretation done by ATLAS.
We explore how the picture changes when also including CMS results, and what can be gained by the statistical combination of analyses.
Our results underscore the need of a broad, multifaceted approach for maximising sensitivity and closing loopholes in the extensive SUSY parameter space.
Finally, I introduce recent progress in the effective field theory tools and the opportunities they offer to test supersymmetric scenarios.
10h30 : Louise Millot (ALICE)
"Jets in heavy-ion collisions and how we can use them to probe the Quark-Gluon Plasma"
Presentation in English
Abstract :
High-energy heavy-ion collisions at the Large Hadron Collider at CERN provide a unique environment to study Quantum Chromodynamics (QCD) matter at extreme energy density and temperature. In these collisions, a deconfined state of nuclear matter known as the Quark-Gluon Plasma (QGP) is formed.
This seminar presents an overview of the QGP and its study within the ALICE experiment, together with the progression of my PhD work towards jet-based observables. Jets, originating from high-energy partons produced in initial hard scatterings, are powerful probes of the QGP as they undergo modifications while traversing the medium.
In particular, the phenomenon of jet quenching reflects medium-induced energy loss through both collisional and radiative processes, leading to modifications of jet energy and internal structure. To investigate these effects in more detail, jet substructure techniques are employed.
Among these, the SoftDrop grooming algorithm will be introduced and discussed, along with the first checks and developments carried out during my PhD work. SoftDrop systematically removes soft, wide-angle radiation from jets, allowing access to the hard splitting structure of the parton shower. This enables the study of medium-induced modifications at the level of the first hard splitting, providing enhanced sensitivity to the mechanisms of parton energy loss in the QGP