The primary idea behind the development of the 17-mile Large Hadron Collider (LHC) was to discover supersymmetric particles, which are thought to exist outside of the collection of particles that constitute the Standard Model (SM) of particle physics. While the LHC failed to do so in the 9 years of its operation, it did confirm the existence of the Higgs Boson (the ‘God Particle’) in 2012 – the last addition to the SM. Since then, high-energy particle physics have been at a standstill, as researchers ponder if any existing physics experiment could ever detect a supersymmetric particle. Supersymmetry, which claims that every existing particle in the SM has a supersymmetric partner, could help explain the existence of dark matter, neutrino masses, and the matter-antimatter asymmetry of the universe. Now, two independent observatories in Antarctica have detected mysterious high-energy particles that, according to the researchers, fits the theory of being classified as supersymmetric.
Since March 2016, such particles were twice detected by NASA’s Antarctic Impulsive Transient Antenna (ANITA). Originally designed to hunt cosmic rays from space, ANITA recorded instances of high-energy particles bursting out of the Antarctic ice. The observations befuddled scientists, as particles of such high-energy cant traverse through solid mass owing to their “large cross-sections”. They didn’t fit into particle physics’ SM and was loosely thought to be either sterile neutrinos (neutrinos that rarely ever bang into matter) or “atypical dark matter distributions” present inside Earth.
However, astrophysicist Derek Fox and his colleague Steinn Sigurdsson at Penn State University weren’t thoroughly convinced by these explanations. They looked for similar events in data collected by other detectors to put forward a more plausible explanation regarding the nature of the mysterious particles. They noticed that IceCube, another large neutrino observatory in Antarctica, had detected such particles three times in its operational history. By analyzing the combined IceCube and ANITA data sets, they made a strong statistical case that no conventional particle would travel through Earth’s crust in a similar fashion. They calculated that the high-energy particles had less than a 1-in-3.5 million chance of being part of the SM.
Instead, Fox and his colleagues argued that the particles are most likely to be “stau sleptons” – the supersymmetric version of an SM particle called the tau lepton. The researchers based their assumption on multiple decade-old publications, in which theoretical physicists predicted that stau sleptons might turn up in neutrino observatories across Antarctica. Nonetheless, the project’s lead scientists and a plethora of other physicists have stated that more data, preferably from other instruments, is required to accurately figure out the exact nature of the particle. At the moment, researchers can only say with certainty that the mysterious particle interacts weakly with other particles present in Earth’s crust, enabling them to make the journey to the surface.
While the findings may be the first step towards cracking supersymmetry, more data is definitely required to achieve absolute certainty. If the assumptions are confirmed in the long-term, physicists could get a glimpse into the nature of supersymmetric particles. Nonetheless, the ANITA anomalies might unlock a dawn of new physics at the LHC, which could help explain the nature of the universe and dark matter.
