# Particles and forces

Beyond the force that holds us back in bed in the morning, there are other four fundamental forces, in Nature.

At the present state of our knowledge, Nature is presented as the result of the composition of the four fundamental interactions (electromagnetic, weak, strong and gravitationalwith a set of elementary particles which can be classified according to how they interact with each other and with respect to these forces.

The Standard Model (SM) of Particle Physics is a theory aimed to describe the elementary constituents of matter and their interactions.

The theory has been soundly confirmed by a variety of direct and indirect measurements performed by several experiments, like those realized at $\textsf{Large Electron--Positron}$ collider ($\textsf{LEP}$), at the $\textsf{Standford Linear Collider}$ ($\textsf{SLC}$),  at the $\textsf{Tevatron}$ and recently at $\textsf{Large Hadron Collider}$ ($\textsf{LHC}$).

The recent discovery to find the last missing piece of the SM, the Higgs boson, was announced at $\textsf{CERN}$ on $4^{th}$ of July 2012 and it completes the model prediction to give mass to the elementary particles.

Anyway, many theoretical limitations of the SM let physicists think that a more fundamental theory should exist. In fact, search for new phenomena beyond the SM constitutes the main goal of the experiments at $\textsf{LHC}$.