Search for particles beyond the Standard Model with the CMS detector

The Standard Model (SM) of particle physics had an extraordinary success in predicting a wide array of new fundamental particles. This includes the charm, bottom and top quarks, and leptons from the third family: the tau lepton and its neutrino; all of which are fermions. The model, which incorporated quantum chromodynamics (QCD), could explain the strong interaction through the exchange of a gluon, which is the mediator of the strong nuclear force. It also successfully predicted the existence of massive $W$ and $Z$ bosons responsible for the weak interaction and the Higgs boson, the particle that gives mass to other particles through the Higgs mechanism, which was discovered in 2012 by both the ATLAS and the CMS experiments. Despite all of its remarkable successes the model still cannot describe, among many others, the matter-antimatter asymmetry, the nature of dark matter, neutrino oscillations or give an explanation why the gravitational force is so much weaker than the others. These point to the need of theories Beyond the Standard Model (BSM) which can explain these issues. One of the widely popular extensions of the Standard Model is Supersymmetry (SUSY), which introduces a new space-time symmetry, known as the R-symmetry, that allows the existence of new particles, which are the so-called ``superpartners’’ of their SM counterparts. The ordinary quantum numbers of the new particles are the same as those of their SM counterparts except their spin which differ by a half-integer. However, the new R-symmetry needs to be spontaneously broken allowing the superpartners to differ in mass, otherwise the new particles must have been found already by now. Supersymmetric could explain many shortcomings of the Standard Model, for e.g./ why the observed Higgs boson is so light and give a new candidate for dark matter in the form of the neutralino, which is often believed to be the lightest superpartner (LSP). It could also provide a potential new way to unify all fundamental forces at very high energy scales. These compelling properties of Supersymmetry gave motivation to search for evidence of the predicted new particles.