I can provide you with some examples of potential falsifiable hypotheses in high-energy physics that were actively being explored or discussed up to that point. Please note that the field of high-energy physics is rapidly evolving, and new hypotheses may have emerged since then. It's always best to consult the latest research and publications in the field for the most current information.
Supersymmetry (SUSY) and the search for supersymmetric particles: One of the longstanding hypotheses in high-energy physics is the existence of supersymmetric particles, which would be partners to the known fundamental particles. Experimental efforts at colliders such as the Large Hadron Collider (LHC) aimed to detect signatures of these particles. Falsification of SUSY would occur if no such particles are found within the energy reach of current or future colliders.
Extra dimensions and their manifestations: Some theoretical models propose the existence of additional spatial dimensions beyond the three we are familiar with. Experimental tests and observations aim to probe the effects of extra dimensions, such as deviations from the predicted behavior of gravity at small scales. Failure to find evidence supporting these extra dimensions could falsify specific models proposing their existence.
Composite models of elementary particles: According to some theories, elementary particles such as quarks and leptons may not be truly fundamental but instead composed of smaller constituents. Experimental searches for evidence of these composite models, either through direct detection or by observing deviations from the predictions of the Standard Model, could potentially falsify such hypotheses.
Dark matter properties and interactions: Dark matter constitutes a significant portion of the mass in the universe, yet its nature remains unknown. Hypotheses propose various types of particles as potential candidates for dark matter. Experimental efforts, including direct detection experiments and searches at colliders, aim to discover or rule out specific dark matter particles and their properties.
Tests of the fundamental symmetries of nature: High-energy physics experiments continually strive to test the fundamental symmetries, such as time reversal symmetry, charge-parity symmetry, and Lorentz symmetry. Deviations from these symmetries in experiments could challenge our current understanding of fundamental physics.
Neutrino properties and mass hierarchy: Neutrinos, once believed to be massless, have been experimentally confirmed to have nonzero masses. However, the ordering of their masses, known as the neutrino mass hierarchy, remains unknown. Ongoing experiments, such as neutrino oscillation studies, aim to determine the hierarchy and better understand the properties of neutrinos.
These are just a few examples of falsifiable hypotheses in high-energy physics, and the field is incredibly diverse with many other potential avenues of exploration. Remember to consult the latest research and scientific literature to stay informed about the most current hypotheses and experimental efforts in the field.