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School of Physical and Chemical Sciences

A World-leading Measurement of the Fundamental Parameter of the Standard Model – the Weak Mixing Angle

Research Group: Particle Physics Research Centre
Length of Study in Years: 4 Years
Full-time Project: yes


Funding is provided via the China Scholarship Council and Conacyt students.  

  • Available to Chinese and Mexican 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

The Weak Mixing Angle (WMA) is a fundamental parameter of the Standard Model of Particle Physics. It describes the mixing between the W and Z boson fields and is closely related to the masses of the W and Z particles. The previous generation of WMA measurements yielded a longstanding discrepancy of more than 3 standard deviations between two renowned experiments (LEP at CERN and SLD in the USA). In 2022 the ElectroWeak sector of the Standard Model was shaken by the publication of a highly precise measurement of the W boson mass found to be incompatible with theoretical predictions. If confirmed, this would indicate the clear existence of new exotic physics. Therefore there is great international attention on new high precision measurements of the WMA, which may see similar deviations from theoretical predictions.

Using a large data set of proton-proton collisions recorded between 2015 and 2025 the ATLAS experiment at the Large Hadron Collider is expected to reach the world’s most precise measurement of the WMA. The focus will be on measuring Z bosons decaying to electron-positron pairs very close to the forward beampipe – an experimentally challenging region with high backgrounds. This region is where the measurement has maximum sensitivity to the WMA.

The project will use a novel method to extract the WMA developed by Prof Rizvi [JHEP 12 (2017) 059]. It uses a state-of-the-art unfolding techniques to correct for detector effects. An advanced profile likelihood fit to simultaneously determine the WMA and the Parton Density Functions (PDFs). This will minimise the largest uncertainty arising from the PDFs – an area where Prof Rizvi has considerable expertise. The method will be applied to a much larger dataset and is anticipated to achieve a precision of better than 26 x 10-5. This will be the world’s most precise measurement from a single experiment.

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 available to Chinese nationals eligible for China Scholarship Council Funding as well as Mexican students via the CONACYT programme.

  • 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/Conacyt.


SPCS Academics: Professor Eram Rizvi