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HEIndividual fellowship2023–2025

HiCoLat · High-precision computations on fine lattices

Horizon Europe — Marie Skłodowska-Curie Actions

Duration
2023-10-01 → 2025-09-30
EU contribution
€210,789
Participants
1
Scheme
HORIZON-TMA-MSCA-PF-EF

Lines connect the coordinator with its partners.

Results in brief

High-precision computations on fine lattices

One of the central goals of particle physics is to test how well the Standard Model describes nature. A particularly sensitive way to do this is through extremely precise measurements of particles’ magnetic properties. The muon, a heavier cousin of the electron, behaves like a tiny magnet. Experiments have measured this magnetic behavior, known as the muon magnetic moment, with stunning accuracy. To fully exploit this achievement, theorists must match this precision in their calculations. Only then can even tiny deviations reveal the presence of new, yet-undiscovered particles or interactions. A key part of the theoretical prediction involves understanding how the strong force influences the muon. This contribution is called the hadronic vacuum polarization (HVP). It can only be calculated reliably using lattice quantum chromodynamics (lattice QCD), a numerical approach that simulates the strong force by representing space and time on a grid. However, these simulations are extremely demanding: achieving higher precision requires much finer and larger grids, which rapidly increases the computational effort needed to obtain reliable results. The HiCoLat project set out to address this challenge. Its objective was to develop and apply improved computational methods that reduce noise and control systematic uncertainties in high-resolution lattice QCD simulations. With these enhanced tools, the project aimed to produce a more precise and reliable determination of the HVP contribution to the muon magnetic moment. In addition, the project explored how the same techniques could benefit other areas of particle physics, including studies of heavy quarks that play a role in current searches for physics beyond the Standard Model.

Data: CORDIS, © European Union

Project objective

Lattice Quantum Chromodynamics (LQCD) is the only known ab-initio approach to compute observables in the non-perturbative regime of the strong interactions of particles and fields. The theory of strong interactions is solved numerically in finite volumes on an Euclidean space-time grid. The framework of LQCD has systematically improvable statistic and systematic uncertainties. It provides highly relevant theoretical input for high-energy and nuclear physics. The precision of LQCD computations has significantly improved in the last years thanks to algorithmic advancements.This project aims to further improve the precision of phenomenologically important observables. The improvement will be achieved by the development and application of noise reduction techniques to reduce statistical uncertainties at computationally challenging, very fine resolutions of LQCD simulations.The focus of this project will be on the improved determination of the hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon. Precise theoretical predictions of this observable are of utmost importance in the search for physics beyond the Standard Model of particles as the uncertainties of the experimental results will significantly decrease in the upcoming years. The computation of the hadronic vacuum polarization in the framework of LQCD suffers from an exponentially enhanced increase of the noise-to-signal ratio in the low energy region. Furthermore, the precision of state-of-the-art determinations is bounded by systematic uncertainties due to the presence of the finite grid. Both uncertainties will be addressed and reduced in this work.Furthermore, the approach will be tested in the computation of B-physics observables that are needed to investigate currently observed anomalies in the heavy quark flavor sector of the Standard Model.

Original text from CORDIS.

Participants

  • ORGANISATION EUROPEENNE POUR LA RECHERCHE NUCLEAIRE · GENEVE 23CoordinatorSwitzerland

Links

Data: CORDIS, © European Union