[HN Gopher] A New Map of All the Particles and Forces (2020) ___________________________________________________________________ A New Map of All the Particles and Forces (2020) Author : frutiger Score : 31 points Date : 2022-04-16 20:26 UTC (2 hours ago) (HTM) web link (www.quantamagazine.org) (TXT) w3m dump (www.quantamagazine.org) | PaulHoule wrote: | What I like of the right-hand, left-hand split is that it | emphasizes the mystery of neutrinos. | | We know neutrinos have a mass, we don't know how much. We don't | know how to incorporate the neutrino mass into standard model. | Other fermions come in left-handed and right-handed forms but we | only see left-handed neutrinos. | | One idea is that right-handed neutrinos do exist but are highly | elusive. In fact they are a good answer to the dark matter and | other physics mysteries | | https://arxiv.org/abs/1303.6912v3 | ncmncm wrote: | That the total mass of neutrinos is commensurate with / exceeds | all the hadronic mass is rarely mentioned. With so many | interactions emitting neutrinos, does everything end up as | neutrinos, finally (neglecting expansion)? Or does something | consume neutrinos and yield net hadronic stuff? | PaulHoule wrote: | Particles like protons and electrons can never turn entirely | to neutrinos because electric charge is conserved. Protons | and bound neutrons seem to be the only stable configuration | of quarks & gluons, ultimately there is quark charge that is | conserved that prevents quarks from going away unless protons | really do decay... which would have to happen at a very low | rate if it does. | est31 wrote: | The article is two years old, and one of the links, the one | pointing to https://www.cpepweb.org/cpep_sm_large.html is already | dead. | | Thankfully the internet archive has a backup: | http://web.archive.org/web/20200521151158/https://www.cpepwe... | tejohnso wrote: | Is this model actually taught in high schools at this point? | | I remember being taught about electrons with their valence | shells, protons, and neutrons. That's it. I didn't hear about a | boson or a neutrino until well into adulthood. | bsedlm wrote: | why is the absolute overwhelming majority of stuff in the | universe (and 100% of things outside of special lab settings) | made up from 1st generation matter? | | why is it that all stuff made from charm, strange, top, and | bottom, quarks decays right away? | green_on_black wrote: | why are there generations at all? why 3? | ncmncm wrote: | Might we just not wield enough energy to evoke a 4th | generation? | PaulHoule wrote: | https://en.wikipedia.org/wiki/Generation_(particle_physics) | #... | frutiger wrote: | > why is the absolute overwhelming majority of stuff in the | universe (and 100% of things outside of special lab settings) | made up from 1st generation matter? | | The first generation have the lowest mass, and there are | interactions between generations. Since physical systems like | to explore the local energy space and find the lowest one, it | follows that more energetic systems will quickly stabilize to | lower energy configurations. | | You might rightfully have two follow up questions at this | point: | | 1. Why do the first generation fermions have the lowest mass? | | 2. Why do physical systems like to find the lowest energy | configuration? | | I don't believe anyone has the answers to those - so far as we | can tell this is just the way the universe is. Maybe some day | someone will figure out why. | ncmncm wrote: | Does thermodynamics not suffice for (2)? Or does that just | restate the question, somehow? | | I learned many things about the SM from this presentation I | had never before retained. | | Wondering now to what degree string theory seems to exactly | require all of this, vs. merely be apparently compatible with | it, insofar as it can be "solved" at all. Where it is too | hard, maybe it is not known whether certain SM features are | compatible, and everyone just hopes? | PaulHoule wrote: | By thermodynamics: energy is conserved globally so when a | protein molecule relaxes to a minimum energy configuration | the energy gets transferred from the protein molecule to | its environment. Total energy stays the same but it is more | spread out. There are dramatically more possible ways the | energy could be spread out than be bunched together: so if | it starts out in a bunched out state it will spread out | unless there is something, usually a "conserved quantity" | or quantum number that makes it impossible for the state to | roam randomly across the phase space. ___________________________________________________________________ (page generated 2022-04-16 23:00 UTC)