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School of Physical and Chemical Sciences

A World Leading Search for Higgs Boson decays to charm quarks at the ATLAS experiment at the LHC

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.  

  • Available to Chinese applicants only.
  • Applicant required to start in September 2024.
  • The studentship arrangement will cover overseas tuition fees for the duration of the studentship.

Project Description

After the discovery of the Higgs boson at the LHC, the Higgs boson Yukawa coupling to matter particles (fermions) has been experimentally confirmed only for the heavy 3rd-generation fermions. Higgs decays into the lighter first and second-generation fermions have not yet been experimentally observed. This project will perform a search for Higgs Boson decays into charm quarks based on the world’s largest dataset collected by the ATLAS detector between 2016 and 2025 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. At the LHC, we have measured this process with data taken from 2016-2018, using the associated production of Higgs bosons with Z or W bosons, and have published an upper limit on the Higgs to charm branching fraction. The sensitivity was limited by the small size of the data set, and the modelling of the background from Z bosons produced in association with quarks. To reduce the uncertainty on the latter, we will perform in the first part of the project a separate cross section measurement of Z production in association with charm quarks and publish the result. This measurement will greatly reduce the uncertainty on the background for the Higgs to charm measurement. We will enhance the performance of both the Higgs to charm and the Z + charm measurements via a sophisticated Graph Neural Network based charm tagging algorithm. In the second part of the project, we will apply these improvements to the search for Higgs bosons decaying to charm quarks in the full ATLAS 2016-2025 data, to obtain a world-leading result.

The QMUL ATLAS group led by Prof Rizvi working with Dr Blumenschein has accumulated extensive experience and leadership in the search and measurements of both Higgs decays to heavy quarks, Z boson decays, and Z boson production in association with charm quarks. This will provide an optimal environment for this PhD project.

Application Method:

To apply for this studentship and for entry on to the Physics programme (Full Time) please follow the instructions detailed on the following webpage:

Deadline for application - 31st of January 2024

Supervisor Contact Details:

For informal enquiries about this position, please contact Professor Eram Rizvi with a full CV.




  • This project is only available to Chinese nationals eligible for China Scholarship Council Funding.


  • The minimum requirement for this studentship opportunity is a good Honours degree (minimum 2(i) honours or equivalent) and MSc/MRes in a relevant discipline (minimum 2(i) honours or equivalent).


  • You will require a valid English certificate equivalent to IELTS 6.5+ overall with a minimum score of 6.0 in Writing and 5.5 in all sections (Reading, Listening, Speaking) at the time of application to the CSC.

SPCS Academics: Professor Eram Rizvi