TOP-QUARK & HEAVY FLAVOURS
Portals to new physics in the QCD and EW sector
The top quark is the most massive of all observed elementary particles. Due to its large mass the top quarks present the strongest coupling to the Higgs boson within the framework of the Standard Model (SM). For that, the top quark becomes an ideal laboratory for detailed tests of the Higgs mechanisms and of many alternative explanations of spontaneous symmetry breaking (EWSB) in Beyond Standard Models (BSM) theories. The future lepton colliders, specially the linear colliders with beam polarisation and high energy reach (ILC, CLIC) are the ideal machines to study in detail its properties and the properties of other heavy quarks which are also highly sensitive to new physics.
The main goal of current and future machines at the energy frontier is to understand the nature of EWSB. This symmetry breaking can be generated by different fenomenas. One of the most widely accepted possibilities is the existence of a newstrong sector, inspired by QCD, that may manifest itself at high energies. In all realisations of the new strong sector, as for example Randall-Sundrum models or compositeness models the strength of the coupling to this new sector of the Standard Model fields are supposed to increase with their mass, therefore the top-quark is the main candidate to be a candle for such type of new physics. However, other lighter fermions (and particularly, other quarks) also play an important role in this type of scenario and any deviation from the Standard Model prediction on their physical parameters will be a clear hint of new physics.
To accomplish this endeavour and probe the Standard Model and beyond with high precision, we require very accurate methods to determine the physical parameters and couplings of the different quarks, and in particular the top-quark and the b-quark. This can only be possibly achieved in lepton colliders such the ILC. In AITANA, we work in developing methods for precise measurements of the quark masses and the electroweak couplings, while we optimize the detector and accelerator requirements to accomplish the largest precision.
AITANA is one of the leading groups in the heavy quark studies for future colliders. We are involved in the Snowmass process and we are taking part in coordination roles in the ILD (A. Irles as co-convener of the Top & Heavy Flavour physics group) and the International Development Team for the ILC-Prelab (with A. Irles as co-convener of the Top & Heavy-Flavour & QCD topical group from the Physics & Opportunities subgroup WG3)