The latest advances in the search for supersymmetrical particles (SUSY) are starting to shape what may be the composition of dark matter. One of the researchers from the group of Experimental Physics of High Energies of the University of Oviedo, Santiago Folgueras, was in charge of showcasing the latest findings made in this field by the experiments developed by the European Laboratory of Particle Physics (CERN), during the meeting of the American Physical Society (APS), which took place last week in Denver (USA).

The Asturian scientist is working on his PhD at the University of Oviedo, on the search for supersymmetrical particles, which may be the components of dark matter. He also collaborates with the CMS experiment at the Large Hadron Collider in Switzerland. During the prestigious meeting of the APS, Folgueras was in charge of presenting the data obtained last year by the CERN. "Despite the fact that these are still preliminary results, they push us further in the right direction in the search for supersymmetrical particles. Not having found them yet gives us more and more clues on where we should be focusing our search", Santiago Folguera explains.

The first analyses of the results of the CMS experiment indicate that these elementary particles may have a higher mass than what was expected, and that is the reason that they had not been detected until now

The research group of the University of Oviedo, alongside the Federal Polytechnic School (ETH) of Zurich and the Insititue of Physics of Cantabria (IFCA-UC), of the search of supersymmetrical particles in process with two leptons of the same sign, in the framework of the CMS. Santiago Folgueras claims that "these kind of processes are very uncommon in the standard framework that we are used to. This makes it a search channel that may immediately show any manifestation of new physics that we may find. The participation of the group has been vital to obtain the results that we have presented in Denver".

The first analyses of the results of the CMS experiment indicate that these elementary particles may have a higher mass than what was expected, and that is the reason that they had not been detected until now. Half of the data obtained during 2012 by the CMS experiment have not been analyzed yet and scientist hope to be able to slowly determine the characteristics of the particle that form dark matter. Their goal is set on 2015, when the energy of the particle accelerator of the CERN goes from 8 to 13 or 14 teraelectronvolts. This energy boost will help with the search for the supersymmetrical particles.

The discovery of the SUSY particles constitutes a further step in the field of physics of elementary particles, which almost a year ago saw a landmark event with the discovery of Higgs boson by the researchers from the CERN. The next step in their experiments is to reveal the components of the dark matter of the universe. "This is about searching without knowing exactly what you're searching for. Thus, we keep on filtering and eliminating until we may be able to define what are the elementary particles we are looking for", Javier Cuevas explains. Cuevas is the lead researcher of the group of Experimental Physics of High Energies of the University of Oviedo.

The Supersymmetry Theory

Javier Fernández Manager of Physics of High Energies in the Group of Experimental Physics of High Energies of the University of Oviedo

Nearing the half of the 20th Century, the field of Physics was revolutionized with the introduction and later discovery of the antimatter: every fundamental particle was proved to have a companion of equal mass, but opposed electrical charge. This idea allowed for the union between Quantum Mechanics and Relativity, creating the Quatum Field Theory.

Nowadays, the Standard Model (SM) of particle physics faces a similar challenge to the discovery of antimatter: as we get closer to the elementary particles in a higher scale of energy, we see that there is a "jump" between the scale of the elementary particles and the shorter distances. The Supersymmetry Theory is an idea (space-time symmetry) that assumes that Nature repeats itself in order to solve similar problems, such as that of antimatter decades ago: every particle would have its supersymmetric companion.

In similar terms, this would be the equivalent to every particle having an independent shadow. The fact that SUSY particles have still not been discovered would be due to the fact that their mass is higher than that of a standard particle, so they would not have been at reach of the energies of the accelerators that came before the LHC. In other words, SUSY is a broken symmetry: as if the light source was shining from below (as in a sunset), creating a shadow that is bigger than the object that casts it. Doubling again the number of particles allows for the cancellation of the processes that had not been explained with the SM with those of SUSY, and the description of nature in smaller scales to those that we work with today.