Taking a closer look at LHC

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

After years of searching and loads of accumulated data from countless collisions, there is no sign of any supersymmetric particle. In fact, many supersymmetry models are now completely ruled out, and very few theoretical ideas remain valid.

Many physicists working on Supersymmetry Theories were shocked when no supersymmetric particles were discovered in the early days of the LHC, and even more so now that many years have passed since the start-up of this accelerator.

The lack of evidence for supersymmetry at the LHC does not signify a death knell for the idea. Nevertheless, now the community is going off in a large number of different directions.

In other section, we present one of the most fashionable ideas currently in vogue in the effort to go beyond the standard model.

Despite this situation, we believe it is interesting to comment briefly on the essential ideas underlying supersymmetry.

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 bosonsA 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 be produced in particle accelerators like LHC at CERN.

We have already mentioned above that this did not happen after an intensive search.


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 Unificationgrand 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.

But we remember again that after years of searching and loads of accumulated data from countless collisions, there is no sign of any supersymmetric particle.




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", "Ramon y Cajal" fellow (Spanish Postdoctoral Senior Grants), and Associate Professor. Since 2023 is Senior Lecturer 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 a Degree in Chemistry, and he is PhD for Santiago University (USC) (ORCID).



CERN Directory

CERN Experimental Program

Theoretical physics (TH)

CERN Experimental Physics Department

CERN Scientific Committees

CERN Structure

CERN and the Environment



Detector CMS

Detector ATLAS

Detector ALICE

Detector LHCb

Detector TOTEM

Detector LHCf

Detector MoEDAL

Detector FASER

Detector SND@LHC



 For the bibliography used when writing this Section please go to the References Section

© Xabier Cid Vidal & Ramon Cid -  | SANTIAGO (SPAIN) |