[School of Natural Sciences PhD Scholarships] Search for a long-lived six-quark state with charm (c) quark in LHCb

About the project

About the Project Six-quark (hexaquark/dibaryon) states, of which the deuteron is a prime example, are of fundamental importance for understanding the structure of matter, long-range hadronic interactions, and the equation of state of neutron stars. While numerous dibaryon candidates have been predicted, the deuteron and the d∗(2380) resonance remain the only experimentally confirmed ones. Throughout the history of hadron physics, the inclusion of heavy quarks (c and/or b) has repeatedly led to major breakthroughs. Prime examples include the discovery of charmonium, recognised by the 1976 Nobel Prize in Physics, and the discoveries of the many exotic hadrons — states containing four or five quarks — from 2003 onwards. We therefore propose to extend the search for dibaryons to systems containing a charm (c) quark. Theory predicts that some of these states could be long-lived, providing a distinctive experimental signature in the form of a displaced decay vertex, while their heavy-quark content also enables a cleaner theoretical interpretation of their measured properties. The project will perform a search for these hypothetical long-lived six-quark states with charm (c) quark using data collected by the LHCb experiment, which is particularly well suited to such a search due to its excellent vertexing and heavy-flavour capabilities. The outcome will be either the discovery of a new state or the setting of an upper limit on its production cross-section times branching fraction. The sensitivity expected from the available LHCb dataset, combined with theoretical expectations for the production rate, makes the discovery of this state feasible for the first time. Non-observation and an upper limit will effectively mean an evidence of it's non-existence or short-lived nature. Either outcome will provide important information for understanding the interactions between quarks and the dynamics of multiquark systems. The successful candidate will join the LHCb Manchester group, which has a strong record of high-quality analyses within the LHCb, and will receive continuous technical and research support. They will also become a member of the LHCb collaboration, providing access to the necessary data, dedicated training, and opportunities for international collaboration and communication. This project is expected to start in September 2027. Before you apply: We strongly recommend that you contact the supervisors for this project before you apply. How to apply: To be considered for this project you must complete a formal application through our online application portal. If you already have an applicant account this link will directly open an application for PhD School of Natural Sciences Scholarships . If you don’t already have an applicant account, please follow the instructions here . When applying, please specify the full title and supervisor/s of the project, details of your previous study, and names and contact details of two referees. You must also upload a Supporting Statement describing your motivation to apply to the project, your CV and transcripts of awarded and in-progress university qualifications . Please note late or incomplete applications will not be considered. Equality, diversity and inclusion are fundamental to the success of The University of Manchester and central to all our activities. A diverse research community strengthens creativity, productivity and quality, while increasing the societal and economic impact of our work. We welcome applicants from all career paths, backgrounds and sections of the community, regardless of age, disability, ethnicity, gender, gender expression, sexual orientation or transgender status. We welcome applications from candidates returning to study after a career break or experience in other roles. Flexible study arrangements may be available, including part-time study at 50%, 60% or 80%, subject to the requirements of the project and funder. Eligibility : The standard academic entry requirement for this PhD is an upper second-class (2:1) honours degree in Physics (or international equivalent) OR any upper-second class (2:1) honours degree and a Master’s degree at merit in Physics (or international equivalent). Basic knowledge of Particle Physics is desirable. This project will remain open until filled. If your application is submitted by 1 st November 2026, you can expect a decision by 18 th December 2026. If your application is submitted by 15 th January 2027, you can expect a decision by 30 th March 2027. Self or externally funded students can also be considered for this project. FSESoNS

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