From Don Lincoln at Fermilab- “Frontier Science Result: CMS Contact!”


Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

Fermilab Don Lincoln
Don Lincoln

“The quarks and leptons of the Standard Model are assumed to be point-like. Note that this doesn’t require that they have no size; it merely means that if we make the simplifying assumption that they have zero size, then we can make predictions that are in good agreement with measurements. The history of fundamental physics is littered with the corpses of physics models of particles once thought to have zero size, from atoms to the protons and neutrons in atomic nuclei. Each of them eventually was shown to have a measurable size and consequently to be made of yet smaller particles.

quark
A proton, composed of two up quarks and one down quark. (The color assignment of individual quarks is not important, only that all three colors be present.) Wikipedia

sm
The Standard Model of elementary particles, with gauge bosons in the fourth column.

For about 50 years, scientists have been poking at the quarks and leptons, trying to see if they are made of something smaller. However, the simple fact is that the success of the Standard Model has actually stymied our progress.

Physicists have theorized on what the building blocks that make up quarks and leptons might be, but because the data agrees so well with the point-like hypothesis, there is no universally agreed-upon theory describing the building blocks at the next-lower level. So physicists simply look at the quarks and leptons at higher and higher energy, which is equivalent to using a more and more powerful microscope. If we start to observe that there is a size at which the particles no longer act like point particles, we’ll have seen our first glimpse at the next-lower set of building blocks.”

See the full article here.

Fermilab Campus

Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics.


ScienceSprings is powered by MAINGEAR computers