Research Group: Particle Physics Research Centre Number of Students: 1 Length of Study in Years: 4 Years Full-time Project: yes
Funding is provided via the China Scholarship Council.
After the discovery of the Higgs boson at the LHC, the Higgs boson Yukawa coupling to matter particles has been experimentally confirmed only for the heavy fermions. Higgs decays into the lighter fermions have not yet been observed. This project will perform a search for Higgs Boson decays into charm quarks based on the world’s largest dataset collected between 2016 and 2026 by the ATLAS experiment at the LHC.
The Standard-Model Higgs boson branching fraction into charm quarks is 3% but new physics beyond the Standard Model could significantly enhance or reduce this. The sensitivity of the most promising production mode, in association with weak bosons, was so far limited by the size of the data set and the uncertainty on the modelling of the background from Z bosons produced in association with quarks. To reduce the uncertainty on the latter, we will perform a separate cross section measurement of Z + charm quarks and publish the result. The performance of both the Higgs to charm and the Z + charm measurements will be enhanced via a novel charm tagging algorithm based on Graph Neural Networks. We will apply these improvements to the search for Higgs bosons decaying to charm quarks in the full ATLAS 2016-2026 data. We will further develop an algorithm based on Deep Neural Networks, to optimally separate the Higgs signal from backgrounds and obtain a world-leading result.
The QMUL ATLAS group has accumulated extensive experience and leadership in the search and measurements of both Higgs decays to heavy quarks, Z boson decays, Z boson production in association with charm quarks and charm tagging. This will provide an optimal environment for this PhD project.
Supervisor Contact Details:
For more information on this project please contact Ulla Blumenschein (u.blumenschein@qmul.ac.uk).
Deadline - 29th of January 2025
Application Method:
To apply for this studentship please select September entry in the following page:
https://www.qmul.ac.uk/postgraduate/research/subjects/physics.html
The minimum requirement for this studentship opportunity is a good Honours degree (minimum 2(i) honours or equivalent) or MSc/MRes in a relevant discipline.
If English is not your first language you will require a valid English certificate equivalent to IELTS 6.5+ overall with a minimum score of 6.0 in all other categories.
SPCS Academics: Dr. Ulla Blumenschein