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Accueil du site > Emploi/Formation > Thèses - Stages de M2

Search for new phenomena through polarisation studies of vector bosons at LHC

Since the observation of the Higgs boson in 2012 at the LHC, so far, no evident signs for the existence of new particles beyond the Standard Model (SM) was observed in direct searches. However, a few aspects of the Standard Model still remained inaccessible, mostly because of the lack of sufficient data to precisely measure some of its rare processes.

Among such processes is the production of pairs of gauge boson and the characterisation of the self-interaction of gauge bosons. In particular, the polarisation states of W and Z bosons produced by pairs, and the correlations between the polarisation states of the two bosons, could bring new information that have never been exploited so far to look for deviations to Standard Model predictions. Exploiting this polarisation information could lead to indirect constraints on the existence of new physics.

The master 2 internship proposed is on the measurement of the longitudinal and transverse polarisation final states of the bosons of WZ diboson events. Already at the start of his work, the candidate will have access to the full data set collected by the ATLAS experiment at a centre-of-mass energy of 13 TeV and amounting to 140 pb-1. The work will be devoted to the development of novel techniques to separate longitudinal and transverse polarisation states of the bosons, exploiting advanced machine learning methods. The candidate will work within the larger working group on WZ dibosons of the ATLAS Collaboration, working group co-led by the LAPP team.

Supervisor : Emmanuel Sauvan (

Detailed subject :