The Search for Supersymmetric Particles at the Large Hadron Collider

The Large Hadron Collider (LHC) is the perfect environment for the search of new particles. Scientists believe that the theory of supersymmetry holds the key to the existence of partner particles for each known fundamental particle. These supersymmetric particles could potentially provide answers to various unresolved questions in science, including the origin of dark matter, the small mass of the Higgs boson, the anomalous behavior of the muon spin, and the relationship between different forces of nature. However, the question remains: Where are these supersymmetric particles hiding?

The ATLAS collaboration, in a recent study of proton-proton collision data from Run 2 of the LHC, presents the most extensive overview of its searches for elusive types of supersymmetric particles. These particles are produced rarely through the weak nuclear force or the electromagnetic force. The lightest of these weakly interacting supersymmetric particles could potentially be the source of dark matter. With the enhanced collision energy and higher collision rate of Run 2, along with new search algorithms and machine-learning techniques, ATLAS physicists have been able to delve deeper into the realm of supersymmetry.

ATLAS researchers have combined results from eight different searches, each designed to detect evidence of supersymmetric particles in a unique way. This comprehensive approach allows for the exploration of tens of thousands of supersymmetry models, each predicting different masses for supersymmetric particles. The sensitivity and power of the search strategies employed by ATLAS are unparalleled, covering a wide range of supersymmetric particle masses.

One intriguing aspect of ATLAS’ search is the quest for “lab-made” dark matter, which refers to dark matter created in the collisions at the LHC. This complements other experiments that focus on detecting natural, relic dark matter leftover from the Big Bang. While collider searches do not require direct observation of dark matter, relying instead on inference, other experiments detect dark matter particles by their interaction with normal materials. By ruling out certain regions of supersymmetric-particle masses, ATLAS’ searches have advanced our understanding of dark matter.

Through their comprehensive study, ATLAS physicists have made a significant finding: regions favoring supersymmetric-particle masses, where the dark matter particle has roughly half the mass of the Z boson or the Higgs boson, have now been heavily disfavored. This elimination highlights the power of ATLAS’ search strategies and provides valuable insights into optimizing future searches.

Despite the progress made in narrowing down the potential hiding places for supersymmetric particles, many models still elude scientists. Additional collision data and further advancements in search strategies will be necessary to improve the sensitivity of ATLAS’ searches to these elusive models. The search for supersymmetry continues, driven by the curiosity and determination of researchers at the LHC.

The Large Hadron Collider, with its vast capabilities, is an ideal platform for the search for supersymmetric particles. The ATLAS collaboration’s comprehensive study of proton-proton collision data has provided unprecedented insights into the existence and properties of these elusive particles. While some regions of supersymmetric-particle masses have been ruled out, the search for hidden models continues. With advancements in technology and the accumulation of more collision data, scientists are hopeful that new discoveries will shed light on the mysteries of the universe and push the boundaries of our understanding of fundamental physics.