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advanced_notions:elementary_particles [2018/04/09 08:46]
tesmitekle [FAQ]
advanced_notions:elementary_particles [2018/04/14 08:08] (current)
aresmarrero [Abstract]
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 <tabbox Abstract> ​ <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>​
advanced_notions/elementary_particles.txt · Last modified: 2018/04/14 08:08 by aresmarrero