The electroweak and gravitational structure of the nucleon

• Applicant: Privatdozentin Dr. Sara Collins, Ph.D.
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 459819809

The need for a more precise knowledge of the distribution of quarks and gluons inside the nucleon is so urgent that a new large scale experimental facility is being constructed at the BNL, the electron ion collider (EIC), whose main objective is to explore the many facets of nucleon structure. For instance, most experimental searches for new physics beyond the Standard Model, involve nucleons as probes, this includes collider experiments such as at the LHC, long baseline neutrino oscillation experiments and direct dark matter detectors. To uncover the interactions between the quarks and gluons inside the nucleon with other particles, precise knowledge of nucleon structure, i.e. the distribution of the partons within the nucleon and their response to electroweak (and non-Standard Model) probes is required. Moreover, electroweak nucleon structure observables also constrain elements of the energy momentum tensor within the nucleon, to which gravity couples.In lattice QCD simulations, these are directly accessible.The main objectives of this project are to determine the components of the longitudinal momentum and spin sum rules and the shear pressure sum, investigating the main sources of systematic uncertainty via lattice QCD simulations. The project involves the analysis of the relevant u, d and s quark generalised form factors (GFFs), the calculation of the gluon GFFs and determination of the factors matching the lattice matrix elements to the modified minimal subtraction scheme. Novel features of the proposed simulations are the systematic investigation of the flavour singlet sector and a controlled continuum limit.

• DFG Programme: Research Grants