The edge of modern physics: beyond the Standard Model
Nivethan Sathananthan
The Standard Model and its current achievements
Looking back on the evolution of physics in the 20 th century, one of the most groundbreaking theories created was the Standard Model of particle physics, which describes three out of the four fundamental forces of nature, alongside all elemental particles currently known. Ever since 2012, with the successful detection of the Higgs Boson at CERN, 1 every undiscovered fundamental particle 2 that was originally predicted by the Standard Model has been detected and accounted for. In spite of these achievements, the Standard Model itself is an incomplete theory, due to its inability to unify what can be described as the two most important theories in modern physics – general relativity and quantum mechanics, alongside some discrepancies between theory and experimental data. With these issues in mind, this essay will explore the current limitations of the Standard Model, from unexplained concepts to conflicts with physical observations, along with exploring the current attempts at explanation. I will also be evaluating the more hypothetical explanations for these flaws in the current theories, their current inability to be tested, and the next steps for particle physics as a whole.
Flaws with the Standard Model
Currently, the end goal of physics is to unify quantum mechanics and general relativity into an all- encompassing ‘theory of everything’, although this is currently seen as unachievable, a s one of the major omissions of the Standard Model (SM) so far has been gravity. Despite being one of the fundamental forces in physics (as well as probably being the most well known), it has yet to be included. While there has been theorizing about a particle that carries the force, similarly to how photons act as force carriers for the electromagnetic force, the elusive ‘graviton’ 3 has yet to be detected. This has led to a shrinking of scope, as physicists currently aim to unify the remaining 3 forces 4 into a ‘grand unifying theory’, 5 even without general relativity.
There is also no mention of dark matter or dark energy, the former being responsible for the unseen mass of galaxies, and the latter believed to be responsible for the accelerating expansion of the
1 The particle associated with the Higgs field, which is what gives all particles mass; see ATLAS Collabaration, 2012: 20. 2 The top quark, tau neutrino, and Higgs bosons were detected after the Standard Model was created in the 1970s. 3 See CERN, ‘Extra Dimensions, Gravitons, and Microscopic Black Holes’. 4 The electromagnetic, weak nuclear and strong nuclear forces. 5 See Hawking, 1988: 83-84.
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