Much of the current research involves the Higgs Boson. It is the missing piece in the puzzle of nature. The Standard Model describes all the forces we understand today except for gravity, namely the electromagnetic force, the strong (colour) force and the weak force.
The force you may be familiar with is the electromagnetic force. This has been understood for many years. Only since the 1970s have scientists understood the strong and weak forces almost equally well. The LEP high energy project has given researchers the ability to make precision tests of the standard Model. It gives a complete description of the natural world to ofders of one-thousandth the size of an atomic nucleus.
The Higgs particle is connected with the weak force in the same way that electromagnetism describes particles interacting with photons. The weak interactions describe particles (the W and Z particles) interacting with electrons, neutrinos, quarks and other particles. In many respects, the particles are similar to photons, but also strikingly different. Photons are theoretically massless, but the W and Z particles are massive by comparison to a proton having roughly 80 times as much mass.The huge mass of the W and Z particles is a puzzle. Simply postulating that these particles interact with the known elementary particles, with their huge masses introduces inconsistencies. The Standard Model would then predict that the probability of two high energy particles colliding with one another would be greater than one, a physical impossibility! Therefore, other particles must also exist, and the simplest models suggest the Higgs boson. Other more exotic proposals suggest that there may be several Higgs bosons, entirely new types of strong interactions and a possible new fundamental physical symmetry, called supersymmetry.
If there is a Higgs boson whose mass is less than that of the Z particle then LHC is our best hope of detecting it. The Higgs boson is a critical ingredient to complete our current understanding of the Standard Model, the theoretical edifice of particle physics. Different types of Higgs bosons, if they exist, may lead us into new realms of physics beyond the Standard Model.
The LHC supermagnets and cooling system