Tuesday, April 30, 2019

Most Of The Standard Model Is Irrelevant Most Of The Time

This is cut and pasted from an answer that I provided at Physics Stack Exchange to a question regarding the impact that second and third generation quarks have in our daily lives:

Every nucleon has what are called sea quarks in it, in addition to the valence quarks that define the nucleon as a proton or neutron. Some of those sea quarks, especially the strange quarks, have some secondary relevance in practical terms regarding how the residual strong nuclear force between protons and neutrons in an atomic nucleus is calculated from first principles and how stable a free neutron is if you calculate that from first principles. Strange quarks are also found in the Λ0 baryon (which has quark structure 𝑢𝑑𝑠), which is present at a low frequency in cosmic rays, but has a mean lifetime of only about two tenths of a nanosecond and is only indirectly detected in the form of its decay products.

Strange quarks are also relevant at a philosophical level that could impact your daily life, because mesons including strange quarks called kaons, are the lightest and most long lived particles in which CP violation is observed; thus, strange quarks are what made it possible for us to learn that the laws of physics at a quantum level are not independent of an arrow of time.

You could do a lot of sophisticated engineering for a lifetime without ever knowing that second or third generation quarks existed, even nuclear engineering. Indeed, the basic designs of most nuclear power plants and nuclear weapons in use in the United States today were designed before scientists knew that they existed. The fact that protons and neutrons are made out of quarks was a conclusion reached in the late 1960s and not widely accepted until the early 1970s, although strange quark phenomena were observed in high energy physics experiments as early as the 1950s. Third generation fermions were discovered even later. The tau lepton was discovered in 1974, the tau neutrino in 1975, the b quark in 1977, and the top quark in 1995 (although its existence was predicted and almost certain in the 1970s).

Otherwise, these quarks are so ephemeral and require such concentrated energy to produce, that they have no real impact on daily life and are basically never encountered outside of high energy physics experiments, although some of them may be present in and influence to properties of distant neutron stars. Second and third generation quarks also definitely played an important part in the process of the formation of our universe shortly after the Big Bang.

The only second or third generation fermion in the Standard Model with significant practical engineering applications and an impact on daily life and on technologies that are used in the real world are muons (the second generation electron). Muons are observed in nature in cosmic rays (a somewhat misleading term since it doesn't include only photons) and in imaging technologies similar to X-rays but with muons instead of high energy photons. Muons are also used in devices designed to detect concealed nuclear isotypes. Muons were discovered in 1937, although muon neutrinos were first distinguished from electron neutrinos only in 1962, and the fact that neutrinos have mass and that different kinds of neutrinos have different masses was only established experimentally in 1998.


neo said...

i know this is off-topic but do you ever cover medical news?
I've just learned of a new form of dementia LATE which mimics alzheimer's.

andrew said...

Usually I cover medical news at Wash Park Prophet. I did see that story. I cover it there because medical news frequently has a potential political or social policy dimension and I try to keep that kind of stuff off this blog which is pretty much pure science.

neo said...

I didn't have any interest in Alzheimer's until my mother was diagnosed with it.

So now I'm reading about it everyday, I'm looking at exercise to green tea to fish oil to vitamins and minerals.

andrew said...

Almost everything I've written about the subject since 2005 can be found at this link:


neo said...

oh thanks.

I've done my own research as well.

do you know if they can test for ApoE4, and is this something an internist can order?

also, wouldn't statins or niacin or omega 3 modify ApoE4 if that does cause ALZ?

my research i also saw the herpes suggestion, but also gingivitis and ApoE4 and activated microglia among others, list goes on.

andrew said...

You can test for ApoE4 with a simple 23&Me genetic test that cost about $100. You spit in a tube and in two or three weeks you've got the results. https://www.alzdiscovery.org/cognitive-vitality/blog/new-test-makes-it-easy-to-learn-your-apoe-status-but-should-you

andrew said...

There are also medical grade DNA tests. I actually have a client that is in the business of helping patients and clients arrange to get the medical grade DNA tests for a variety of purposes (which cost about $1,000 but can be covered by insurance or Medicare/Medicaid). I don't know where you are geographically, so it's hard to know if they're at a place near you (I live in Colorado and most of my clients even with quite big businesses tend to have a footprint mainly in the Western U.S.). They guys whom Razib Khan works with professionally, also have a direct to consumer DNA testing service which as I understand it has higher coverage and is closer to the medical grade. http://insito.me/

neo said...

I was thinking along the lines of an internist and covered by Medicare and Aetna, as my mother has that.

currently she's taking generic aricept and namenda, and our copay is really small. as well as simvastatin.

if ApoE4 causes ALZ, i wonder if switching simvastatin to rosavastatin (crestor), and perhaps niacin to increase HDL and fish oil will mitigate apoE4.

i've also looked into shingrex for herpes but shingrex is a huge back order. the MD won't prescribe valtrex as there's no suspicion of herpes.

she does have type 2 diabetes, she was taking insulin, she got dangerously low so we took her off it, and put her on metformin, a1c 6.3. internist is happy, as it follows published guidelines but i want it lower, around 5.7 since she also has ALZ