This is a tricky question as at this time we are currently sat on the divide between potentially proving either answer. The Standard Model has explained years of experimentation at Particle Colliders to extraordinary accuracy and indeed is currently the most proven model of the physical world. Within the model twelve particles are proposed as the building blocks of matter and four force carriers explain all the interactions between them, all except Gravity. Over time, emerging phenomena have stretched the model almost to breaking point and questions are now being asked about its completeness. One proposed extension to the Standard Model is a Supersymmetric one (SUSY). SUSY has already explained and predicted phenomena beyond the Standard Model but still lacks direct experimental evidence. SUSY is popular amongst Scientists as the Standard Model still exists as a subset within this wider and grander theory.
The Standard Model, with its three generations of particles and corresponding anti-particles can explain the Strong, Weak and Electromagnetic interactions but not Gravitational attraction. Unification of the forces is problematic in the Standard Model and the elusive Higgs Boson predicted by the theory has implications with regards to the origin of mass. Once the Higgs Boson is introduced, quantum mechanical fluctuations raise the Higgs mass to a scale much larger than indirect observation would suggest, a consequence known as the Hierarchy Problem. Furthermore there is no Standard Model particle that has the correct properties to account for the Dark Matter that is believed to dominate the Universe.
SUSY solves all these problems and introduces the perfect candidate for dark matter; the Lightest Supersymmetric Particle (LSP). There are many sub-theories under the heading of Supersymmetry but perhaps by Ockhams Razor one should start with the simplest, the Minimal Supersymmetric Standard Model (MSSM). The MSSM proposes a one to one mapping of Standard Model particles onto their respective super-partners, with equivalent quantum numbers except for the super-partner spins which differ by one half. The MSSM additionally can include two super-partners to the Higgs and super-partners to any gravity mediating Boson. A general property of SUSY is that the decay of a super-particle must yield at least one super-particle in the final state, with the lightest such particle being stable. This is the perfect dark matter candidate, earning the theory a lot of respect from Physicists around the World.
SUSY must be a broken symmetry since we do not see two sets of identical particles in experiments. We expect this breaking to occur through the particle masses with the super-partners being much heavier than their Standard Model counterparts. The Large Hadron Collider at CERN will probe this mass range with collision energies up to 14TeV. It is here that we expect to encounter evidence of SUSY and enter a new era of Particle Physics.
All we can do for now is sit tight and wait.
