Taking a closer look at LHC

Supersymmetry

Supersymmetry (SUSY) is a proposed property of the universe. It is one of the best motivated extensions of the Standard Model, so the study of SUSY is a primary goal of the LHC.

Supersymmetry requires every type of particle to have an associated supersymmetric particle, called its superpartner. The superpartner is a heavy replica of a particle, with one other significant difference. All particles are classed as either fermions or bosons. A particle belonging to one class has a superpartner in the other, thereby "balancing the books" and making nature more symmetric. For example, the superpartner of an electron (a fermion) is called a selectron (a boson).

These supersymmetric particles, or sparticles,have the same charge but opposite spin to the particles we’re familiar with, such as photons and electrons.
Supersymmetry describes a new image of our universe formed of pairs of particles, but we can currently see only one partner from each pair. The unseen particles might be the source of the mysterious "dark matter" in galaxies. Although superpartners have not yet been observed in nature, they might soon be produced in particle accelerators like LHC at CERN.

This symmetry, which may have existed in the very early, high-energy universe, could be detectable with the ATLAS and CMS experiments. If the LHC makes supersymmetric particles, their lifetimes will be fleeting. But physicists can deduce their presence from the more-stable decay products. In at least one case, such SUSY clues could also be evidence for dark matter.

The lightest of these sparticles may be a major part of the cosmic dark matter that we know exists but cannot yet describe or detect.

Grand Unification, grand unified theory, (GUT) predicts that at extremely high energies (above 10¹⁶ GeV), the electromagnetic, weak nuclear, and strong nuclear forces are fused into a single unified field.

Supersymmetry, specifically a version called the minimal supersymmetric model, achieves the grand unification more naturally, with far less fine-tuning. The theory predicts five Higgs bosons of different masses, which makes the process by which the universe gets its mass more complicated than that laid out by the standard model with its single Higgs.

http://lhcb.web.cern.ch/

AUTHORS

Xabier Cid Vidal, PhD in experimental Particle Physics for Santiago University (USC). Research Fellow in experimental Particle Physics at CERN from January 2013 to Decembre 2015. He was until 2022 linked to the Department of Particle Physics of the USC as a "Juan de La Cierva" and "Ramon y Cajal" fellow (Spanish Postdoctoral Senior Grants), and he is currently Associate Professor in that Department.(ORCID).

Ramon Cid Manzano, until his retirement in 2020 was secondary school Physics Teacher at IES de SAR (Santiago - Spain), and part-time Lecturer (Profesor Asociado) in Faculty of Education at the University of Santiago (Spain). He has a Degree in Physics and in Chemistry, and he is PhD for Santiago University (USC) (ORCID).

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