How large is the proton? York University Wednesday Dec. 6

I have completely fallen down on my plan to blog at least once biweekly. I'm going to catch up on blogging all the PD I've been doing though, and I'm going to try to get them done before the break.Consider it a pre-holiday present.

For TDSB teachers, make sure to sign up for the Technology-Enabled Learning sessions (aka the after school workshops) on K2L. For LN24, there are a number of sessions you can still attend this and next month.  Note the change to the Virtual Library session. Sign up now!

Wednesday night I attended York U's open-house night for high school physics teachers. hosted by the Physics and Astronomy Department. It's a great evening of PD, not just because they serve dinner with wine, but also it's a chance to learn about some of the ground-breaking research taking place right now. The topic this year was "How large is the proton?  ̶   the proton size puzzle".

During dinner, there were three 15-minute talks, which is an excellent length. The first was from Dr. Randy Lewis. He talked about how my previous 3-quark understanding of the proton (seen below in the basic Wikipedia image)...

By Arpad Horvath (Own work) [CC BY-SA 2.5 (https://creativecommons.org/licenses/by-sa/2.5)], via Wikimedia Commons

...is incomplete; the masses of the three quarks make up less than 1% of the mass of the proton. In reality, at least as far as we currently understand, what we have is much more complicated: at any given time, uncountable pairs of quarks and anti-quarks are appearing and disappearing (along with the associated gluons), and the whole thing somehow makes sure that three valence quarks are always unpaired, as in the picture below, grabbed from phys.org

The blue circle isn't really there. As with everything, protons are mostly empty space. The green circles represent quarks, the orange antiquarks, and the springs are gluons.

Because of this hurricane of energy, current theoretical attempts to calculate the size of the proton aren't there yet, so we need to turn to experiment (the subject of the next two talks).

Dr. Eric Hessels firstly blew our minds by telling us that because of this  –            We can determine the size using atoms – but atoms with electrons and atoms with muons give different answers.
Dr. Marko Horbatsch –    Maybe scattering electrons off of protons can determine the size – but maybe it can’t.