Research

One of the biggest unresolved questions in physics is why there is a hierarchy of many orders of magnitude between the strength of the forces described by the Standard Model (electroweak and strong) and the gravitational force. A unified description of all forces in a common theory must explain this hierarchy. The data that will be provided to the CMS experiment by the Large Hadron Collider (LHC) in the following years may finally shed light on this question.

W, Z and Higgs bosons decay predominantly into quarks which transform into sprays of particles called jets. In high energy proton-proton collisions at the LHC, the W/Z/H bosons can have such a large momentum that their decay products merge into a single particle jet. What is usually done to identify the decay products of the W/Z/H bosons as separate objects no longer works as they are merged in a single jet. It is therefore important to understand the substructure of these jets to identify the W/Z/H bosons by what is called W/Z/H-tagging.

Planning for several accelerator and detector upgrades as well as future colliders are going on in parallel to LHC data taking. In 2023 an upgrade of the LHC to the HL-LHC is planned to reach a total integrated luminosity of 3000/fb. While this allows to explore higher energy and lower probability physics processes, it comes with an additional experimental challenge.