Hola! I'm Alexa Guido, a young and curious woman passionate about science. Join me on an exciting journey to explore the wonders of the universe through the lens of physics.
Can you imagine that with just 17 Lego blocks, you could construct everything from stars and black holes to the water we drink and even our own bodies? This journey spans from ancient Greek philosophers to collisions of particles at speeds nearing the velocity of light, in an effort to understand the very fabric of our universe! Welcome to the fascinating world fo the Standard Model of Particle Physics!
The Standard Model consists of 17 fundamental particles, before the 1970s there was a complete zoo of particles and a lack of understanding regarding their interactions and properties. Today, all these particles are split into two main categories: fermions and bosons.
Fermions are the building blocks of matter meanwhile bosons, are responsible for all of the interactions between matter. Essentially, everything in the universe is found to be made from a few basic building blocks called fundamental particles, governed by four fundamental forces.
On the left side of this table, you will find the 12 fermions, which include six quarks, and six leptons. These 6 particles are related in pairs or “generations” [1]. The lightest and most stable particles make up the first generation, whereas the heavier and less stable particles belong to the second and third generations.
The first generation is the “up quark” and the “down quark”, followed by the “charm quark” and “strange quark”, then the “top quark” and “bottom (or beauty) quark”.
All matter we observe is composed of first-generation particles. For instance, the proton is made up of two up quarks and one down quark, while the neutron is made up of two down quarks and one up quark. We will touch on the electron later, but for now, we are not going to inquire into the intricate mathematical concepts behind the reason for this.
In addition, the six leptons are similarly arranged in three generations, the old acquaintance “electron” and the “electron neutrino”, the “muon” and the “muon neutrino”, and lastly the “tau” and the “tau neutrino”. The electron, the muon, and the tau possess an electric charge and a sizeable mass, while the neutrinos are electrically neutral and have minimal mass. [2]
Turning our attention to bosons, we have five of them, but they mediate three of the four fundamental forces in nature: the strong force, the weak force, and electromagnetism.
The strong force is carried by the “gluon”, which holds quarks together to form protons, neutrons, and a variety of more exotic large particles. That being so, the weak force causes radioactive decay thanks to the “W” and “Z bosons”. Furthermore, the electromagnetic force is carried by the “photon” [3] which is responsible for magnetism and electricity, holding atoms together and even stopping us from walking through walls.
The fourth, missing force, gravity, is crucial in our daily lives, yet at the atomic scale, it’s so weak it can be ignored in almost all situations; and we have not found any force-carrying particle.
Lastly, the Higgs boson plays a vital role by providing mass to particles, and the Higgs field would need to permeate the universe, and all of space would be filled with a sea of virtual Higgs bosons.
Despite we have a remarkable knowledge of the Standard Model, physicists recognize it does not explain everything. There remain significant gaps, such as dark matter or anti-matter. This is why the existence of experiments like the LHC at CERN or the Fermilab is essential, the new insights from these experiments will help us to find more of these missing pieces.
[1] For a detailed explanation of the generations of fundamental particles, see “Have you ever heard about neutrinos?”
[2] Learn more about neutrinos in “Have you ever heard about neutrinos?”.
[3] Learn more about photons in “Have you ever heard about photons?”
Sources:
Images:
Comments