3 ms·
The proton is very fundamental. Almost all of the visible matter around us is either protons or neutrons, and their mass is almost completely generated dynamica
by davrosthedalek 9y ago
The proton is very fundamental. Almost all of the visible matter around us is either protons or neutrons, and their mass is almost completely generated dynamically from QCD (forget Higgs). Its size and mass are cornerstones. Being able to calculate them from first principles would be an enormous achievement.
For me, it's mainly interesting because two different fields of physics meet, nuclear physics (electron scattering) experiments, and atomic physics (spectroscopy).
Otherwise, it's the same as with all basic science. We don't know what it is "good for" until somebody figures out how to cure cancer with it.
The paper this article refers to is in particular interesting, because it finds a value not in agreement with earlier measurements of the /same/ type. The indicated 3.3 sigma shift in the Rydberg constant, one of the most exact measured quantities in existence, is a little bit worrying, but such shifts happen more often than they should.
- QAPereo 9y agoJust to add for GP’s benefit, QCD is monstrously complex, like electric charge x 3, which explains why the achievement would be so enormous.
- davrosthedalek 9y agoYeah, the real problem is that the theory is mostly non-perturbative, i.e. it's hard to phrase the theory as a power series. The underlying reason is that gluons can self-interact.
- jessriedel 9y agoNot just self-interact, but self-interact strongly. Photons can self-interact too, through intermediate charged particles, but do so much less often.
- QAPereo 9y agoTo be fair, the photon self-interaction is usually negligible (barring the right medium and high energies), while for gluons it’s most of the story. Unless you’re looking at exotic situations, photons are well behaved, but gluons are many flavors of pain.
- killjoywashere 9y agoI'm a physics major, and still in science 20 years later, cancer research. I originally came here to ask, in general, why would anyone care about this result? Since you asserted an answer to the question before I managed to ask, I'm happy to subordinate my question. But I will also suggest your specific answer, cure cancer, won't work. I need to kill cells, which requires a cascade of large molecules interacting at energies on the order of a fraction of an eV, or massive amounts of high energy radiation. I can kill cells directly with high energy radiation, however, the energies for this investigation, the hydrogen 2s-4p transition, (1,2) are trivial (486 nm is visible light). Also, radiotherapy isn't really good at interrogating cell type, the current standard for new cancer therapies (immunotherapy). (1) http://science.sciencemag.org/content/358/6359/79 http://science.sciencemag.org/content/358/6359/79 (2) https://indico.mitp.uni-mainz.de/event/14/contribution/11/material/slides/0.pdf https://indico.mitp.uni-mainz.de/event/14/contribution/11/ma...
- TheSpiceIsLife 9y agoI don't think the parent comment meant that literally. Sometimes we don't know what new knowledge will enable us to do until the PhDs, engineers, and technicians get their hands on it.
- miemo 9y agoIt's like finding out your friend since childhood is 3 years older than you always thought. People care because it's jarring that something so 'known' and basic might be different. And yeah the cancer part was more a 'holy grail' thing. replace it with 'cures poverty' and his point still stands