Advanced study may open up doors for new models in particle physics
Quark confinement is one of the most difficult problems in particle physics. These elementary particles cannot be isolated and thus directly observed, but rather clump together to form groups or hadrons. Therefore, they cannot be studied or observed in any more direct way than at a hadron level. Quantum chromodynamics (QCD) explains how quarks and gluons are bound by strong interactions to form hadrons such as the proton and the neutron. The dynamics of quark confinement can be parameterised in terms of so-called hadronic matrix elements. Within the EU-funded project HPFPLATTICEQCD (High precision flavour physics using lattice QCD) scientists devoted themselves to provide highly precise calculations of the hadronic matrix elements needed for the analysis of current and forthcoming experimental data using lattice QCD. The ultimate aim was to conduct rigorous experimental tests of the standard model – the theoretical foundation of particle physics – and put constraints on possible new theories beyond the standard model. The team carried out numerous studies on different flavour observables, obtaining in most cases the most precise results on quantities and reducing uncertainties in previous studies. Theoretical predictions showed good agreement with experimental results. Results can be used by other research teams in the search for new physics and for establishing constraints on new theories. Further, scientists found several tensions in standard deviations between the standard model predictions and experimental measurements, as well as inconsistencies in the standard model description. Several of these differences point to an emerging global tension, and could be explained by contributions from physics beyond the standard model. Additional work is needed to confirm existence of these tensions. HPFPLATTICEQCD made important progress in precisely describing deviations from the standard model predictions. Such deviations, which cannot be explained by the standard model, may open up exciting new possibilities in particle physics.
Keywords
Particle physics, quarks, colour confinement, lattice QCD, standard model
