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advanced_notions:elementary_particles [2017/11/22 13:31] jakobadmin [Researcher] |
advanced_notions:elementary_particles [2018/04/14 10:08] (current) aresmarrero [Abstract] |
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====== Elementary Particles ====== | ====== Elementary Particles ====== | ||
- | <tabbox Why is it interesting?> | ||
- | <tabbox Layman?> | + | <tabbox Intuitive> |
* A nice overview is given here: https://profmattstrassler.com/articles-and-posts/particle-physics-basics/the-known-apparently-elementary-particles/ | * A nice overview is given here: https://profmattstrassler.com/articles-and-posts/particle-physics-basics/the-known-apparently-elementary-particles/ | ||
* [[http://www.ejsme.net/articles/52/523.pdf|Why not start with quarks? Teachers investigate a learning unit on the subatomic structure of matter with 12-year-olds]] by Gerfried J. Wiener, Sascha M. Schmeling and Martin Hopf | * [[http://www.ejsme.net/articles/52/523.pdf|Why not start with quarks? Teachers investigate a learning unit on the subatomic structure of matter with 12-year-olds]] by Gerfried J. Wiener, Sascha M. Schmeling and Martin Hopf | ||
* [[https://gravityandlevity.wordpress.com/2015/04/11/how-big-is-an-electron/|How big is an electron?]] by Brian Skinner | * [[https://gravityandlevity.wordpress.com/2015/04/11/how-big-is-an-electron/|How big is an electron?]] by Brian Skinner | ||
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- | <tabbox Student> | + | <tabbox Concrete> |
+ | {{ :advanced_notions:elemparticles.png?nolink |}} | ||
+ | |||
+ | ---- | ||
<blockquote> | <blockquote> | ||
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<cite>http://thep.housing.rug.nl/sites/default/files/theses/Master%20thesis_Marco%20Boers.pdf</cite> | <cite>http://thep.housing.rug.nl/sites/default/files/theses/Master%20thesis_Marco%20Boers.pdf</cite> | ||
</blockquote> | </blockquote> | ||
- | <tabbox Researcher> | + | |
+ | <tabbox Abstract> | ||
+ | <blockquote>A question not often addressed when discussing the standard model is how one describes physical | ||
+ | particles. Taking the electron as an example, the assumption usually made is that the free Dirac | ||
+ | spinor in the interacting theory, at asymptotic times, can be viewed as an electron since ‘the coupling | ||
+ | switches off’. This would mean that what is being caught in a detector is really a free fermion. The | ||
+ | problem here, of course, is that in QED and QCD the coupling does not switch off, and assuming | ||
+ | it does so generates infrared divergences. As a result, the spinors do not become free even at | ||
+ | asymptotic times [1, 2], nor do they ever become gauge invariant. [...] | ||
+ | |||
+ | The physical picture is of a matter particle | ||
+ | surrounded by a cloud of ‘photons’, neither of which are individually observable, but which together | ||
+ | constitute a gauge invariant, physical particle. This description is nonlocal, which is an immediate | ||
+ | consequence of gauge invariance, but observables calculated with our states are manifestly local and | ||
+ | correctly reproduce classically expected physics. | ||
+ | |||
+ | <cite>[[https://arxiv.org/abs/0907.4071|Stability, creation and annihilation of charges in gauge theories]] by Anton Ilderton, Martin Lavelle, David McMullan</cite> | ||
+ | |||
+ | |||
+ | </blockquote> | ||
+ | |||
+ | ----- | ||
* http://math.ucr.edu/home/baez/qg-spring2003/elementary/ | * http://math.ucr.edu/home/baez/qg-spring2003/elementary/ | ||
* See http://physics.stackexchange.com/questions/33350/particle-as-a-representation-of-the-lorentz-group | * See http://physics.stackexchange.com/questions/33350/particle-as-a-representation-of-the-lorentz-group | ||
* [[http://www.pnas.org/content/99/1/33.full.pdf|A closer look at the elementary fermions]] by Maurice Goldhaber | * [[http://www.pnas.org/content/99/1/33.full.pdf|A closer look at the elementary fermions]] by Maurice Goldhaber | ||
+ | |||
+ | ----- | ||
<blockquote> | <blockquote> | ||
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</blockquote> | </blockquote> | ||
- | + | <tabbox Why is it interesting?> | |
- | <tabbox Examples> | + | |
- | --> Example1# | + | Elementary particles are the fundamental building blocks and also responsible for the fundamental interactions like electromagnetism. |
+ | <tabbox FAQ> | ||
- | + | --> How large is an elementary particle?# | |
- | <-- | + | |
- | --> Example2:# | + | See https://axelmaas.blogspot.de/2018/02/how-large-is-elementary-particle.html?m=1 |
+ | <-- | ||
- | + | -->Why do physicists believe that particles are pointlike?# | |
+ | see https://physics.stackexchange.com/questions/41676/why-do-physicists-believe-that-particles-are-pointlike | ||
<-- | <-- | ||
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