The Large Hadron Collider (LHC) is renowned for its ability to investigate the fundamental nature of the universe. Scientists at the LHC are particularly interested in finding evidence of supersymmetry, which proposes the existence of partner particles for each known fundamental particle. These partner particles could potentially solve various scientific mysteries, such as the origin of dark matter, the mass of the Higgs boson, and the behavior of the muon spin. However, the question remains: where are these supersymmetric particles hiding?
In a recent study, physicists from the ATLAS collaboration at the LHC have conducted an extensive search for elusive types of supersymmetric particles. These particles are believed to be weakly interacting and would only rarely be produced through the “weak” nuclear force or the electromagnetic force. The researchers combined the increased collision energy and rate of Run 2 of the LHC with new search algorithms and machine-learning techniques to explore this challenging territory.
ATLAS physicists employed eight different search strategies to seek evidence of supersymmetric particles. Each strategy targeted a unique way of detecting these particles. By combining the power and sensitivity of these search strategies, the researchers could study tens of thousands of supersymmetry models, each with differing predictions about the masses of these particles. This comprehensive study allowed for unprecedented sensitivity and exploration across a wide range of supersymmetric-particle masses.
One significant focus of the ATLAS searches was the hunt for evidence of “lab-made” dark matter, which refers to dark matter created during collisions at the LHC. These searches complement other experiments that seek natural, “relic” dark matter leftover from the Big Bang. Collider searches do not rely on directly observing dark matter; instead, they infer its presence based on the probability of dark matter particles interacting with ordinary matter. On the other hand, experiments searching for relic dark matter depend on detecting the interactions between dark matter particles and normal materials.
The combination of searches conducted by ATLAS has led to significant findings. Previously favorable regions for supersymmetric-particle masses, where the dark matter particle had approximately half the mass of the Z boson or the Higgs boson, have now been largely ruled out. Additionally, this comprehensive study has shed light on the supersymmetry models that have yet to be explored. ATLAS has identified surviving models that can guide and optimize future searches for supersymmetric particles.
Despite the progress made in narrowing down potential hiding places for supersymmetric particles, numerous models still elude detection. Enhancing the sensitivity of ATLAS searches for these models will require more collision data and further advancements in search strategies. The pursuit of supersymmetry continues, and scientists at the LHC are committed to pushing the boundaries of our understanding of the universe.
The Large Hadron Collider remains at the forefront of the search for supersymmetric particles. The recent study conducted by the ATLAS collaboration represents a significant step forward in exploring this elusive realm of physics. The combination of advanced search strategies and comprehensive analysis has provided valuable insights into the possibilities and limitations of supersymmetry models. While challenges remain, the dedication and ingenuity of scientists at the LHC will undoubtedly lead to further breakthroughs in our understanding of the fundamental forces and particles that shape the universe.