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models:standard_model [2018/03/30 14:35]
jakobadmin [Concrete]
models:standard_model [2019/07/03 08:12] (current)
jakobadmin [FAQ]
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 </​WRAP>​ </​WRAP>​
  
-====== ​The Standard Model ======+====== Standard Model of Particle Physics ​======
  
  
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 **Particle Content** **Particle Content**
  
-{{ :models:standardmodel.png?​nolink&​400 |}}+{{ :models:paper.journal.40.png?​nolink&​800 |}} 
 + 
  
 ---- ----
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 <tabbox Concrete> ​ <tabbox Concrete> ​
-At the hear of the Standard Model is the [[advanced_tools:​gauge_symmetry|gauge symmetry]]+At the heart of the Standard Model is the [[advanced_tools:​gauge_symmetry|gauge symmetry]]
 $$ $$
-G\ =\ SU(3)_C\times SU(2)_W\times U(1)_Y\, .+G\ =\ SU(3)_C\times SU(2)_L\times U(1)_Y\, .
 $$ $$
 The $SU(3)_C$ mixes the three colors of the quarks and antiquarks, The $SU(3)_C$ mixes the three colors of the quarks and antiquarks,
-the $SU(2)_W$ the weak isospin, and the $U(1)_Y$+the $SU(2)_L$ the weak isospin, and the $U(1)_Y$
 couples to the weak hypercharge $Y$. couples to the weak hypercharge $Y$.
  
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 massive ($M_W\approx80.4$ GeV, $M_Z\approx91.2$ GeV) while the massive ($M_W\approx80.4$ GeV, $M_Z\approx91.2$ GeV) while the
 photon $\gamma$ remains massless. photon $\gamma$ remains massless.
 +
 +
  
 ---- ----
 +
 +
 +--> Standard Model Lagrangian#
 +
 +
 +[{{ :​models:​smlagshort.png?​nolink&​800 |Source: http://​blogs.discovermagazine.com/​cosmicvariance/​2006/​11/​23/​thanksgiving/​ }}]
 +
 +  * A nice overview of the various terms in the __Standard Model Lagrangian__ can be found [[http://​www.einstein-schrodinger.com/​Standard_Model.pdf|here]]. A short non-technical discussion of the various terms can be found [[https://​www.symmetrymagazine.org/​article/​the-deconstructed-standard-model-equation|here]]. ​
 +
 +
 +<--
 +
 +-->​Particle Content#
 +
 +{{ :​models:​sm-overview.pdf |The field content of the standard model is nicely summarized here}}
 +
  
 **The Gauge Bosons** **The Gauge Bosons**
-The photon ​couples to the electric charge which is a linear combination of hypercharge and weak isospin+ 
 +The __photon__ ​couples to the electric charge which is a linear combination of hypercharge and weak isospin
 $$ $$
 q\ =\ T^3\ +\ Y . q\ =\ T^3\ +\ Y .
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 The photon is responsible for electromagnetic interactions. Since it is massless the electromagnetic forces are long-ranged. ​ The photon is responsible for electromagnetic interactions. Since it is massless the electromagnetic forces are long-ranged. ​
  
-The $W^\pm$ and $Z^0$ bosons ​are responsible for the weak interactions. Since both are massive the weak force is short-ranged.+The __$W^\pm$ and $Z^0$ bosons__ ​are responsible for the weak interactions. Since both are massive the weak force is short-ranged.
  
-The bosons responsible for the strong force are called ​gluons. This name stems from the fact that they ``glue''​ the quarks and antiquarks together. Bound states made of quarks and antiquarks are called baryons and mesons. ​ The strong forces become stronger with rising distance between two color-chared particles. As a result individual quarks, antiquarks, or gluons can't be isolated. This is known as confinement. Only $SU(3)_C$ singlets can be observed. ​+The bosons responsible for the strong force are called ​__gluons__. This name stems from the fact that they ``glue''​ the quarks and antiquarks together. Bound states made of quarks and antiquarks are called baryons and mesons. ​ The strong forces become stronger with rising distance between two color-chared particles. As a result individual quarks, antiquarks, or gluons can't be isolated. This is known as confinement. Only $SU(3)_C$ singlets can be observed. ​
  
 ---- ----
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 called `up', `down',​ `strange',​ `charm',​ `bottom',​ and `top'. called `up', `down',​ `strange',​ `charm',​ `bottom',​ and `top'.
  
-The left-handed quarks form 9 $SU(2)_W$ doublets: +The left-handed quarks form 9 $SU(2)_L$ doublets: 
-$$(u,d)_L$$(c,s)_L$$(t,b)_L$$+$$(u,d)_L, (c,s)_L, (t,b)_L$$
 (3 for each color) (3 for each color)
  
-The right-handed quarks are $SU(2)_W$ +The right-handed quarks are $SU(2)_L$ singlets.
-singlets.+
  
-This curious difference between left-handed and right-handed quarks ​meanst ​that weak interactions disrespect the parity symmetry. The bosons $W^\pm$ only couple to the left currents $J^\mu_L=V^\mu-A^\mu$+This curious difference between left-handed and right-handed quarks ​means that weak interactions disrespect the parity symmetry. The bosons $W^\pm$ only couple to the left currents $J^\mu_L=V^\mu-A^\mu$
 and don't care about the right currents $J^\mu_R=V^\mu+A^\mu$. and don't care about the right currents $J^\mu_R=V^\mu+A^\mu$.
  
 The same is true for the __leptons__ $e^-$, $\mu^-$, $\tau^-$, and the 3 neutrino species. The same is true for the __leptons__ $e^-$, $\mu^-$, $\tau^-$, and the 3 neutrino species.
  
-The left-handed leptons live in three $SU(2)_W$ doublets: +The left-handed leptons live in three $SU(2)_L$ doublets: 
-$$(\nu_e,​e^e)_L$$(\nu_\mu,​\mu^-)_L$$(\nu_\tau,​\tau^-)_L$$.+$$(\nu_e,​e^e)_L,​ (\nu_\mu,​\mu^-)_L,​ (\nu_\tau,​\tau^-)_L$$.
  
 The right-handed charged leptons $e^-_R$, $\mu^-_R$, $\tau^-_R$ The right-handed charged leptons $e^-_R$, $\mu^-_R$, $\tau^-_R$
-are $SU(2)_W$ singlets. So far right-handed neutrinos were never observed. +are $SU(2)_L$ singlets. So far right-handed neutrinos were never observed.
----- +
- +
- +
---> Standard Model Lagrangian#​ +
- +
- +
-[{{ :​models:​smlagshort.png?​nolink&​800 |Source: http://​blogs.discovermagazine.com/​cosmicvariance/​2006/​11/​23/​thanksgiving/​ }}] +
- +
-  * A nice overview of the various terms in the __Standard Model Lagrangian__ can be found [[http://​www.einstein-schrodinger.com/​Standard_Model.pdf|here]]. A short non-technical discussion of the various terms can be found [[https://​www.symmetrymagazine.org/​article/​the-deconstructed-standard-model-equation|here]].  +
  
 <-- <--
  
--->Particle Content# +-->Standard Model Interactions#
- +
-{{ :​models:​sm-overview.pdf |The field content of the standard model is nicely summarized here}}+
  
 +[{{ :​models:​586px-standard_model_feynman_diagram_vertices.png?​nolink |Source: Image by Garyzx published under the [[https://​creativecommons.org/​licenses/​by-sa/​3.0|CC BY-SA 3.0]] licence}}]
 <-- <--
 ---- ----
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 <​cite>​http://​math.ucr.edu/​home/​baez/​week253.html</​cite>​ <​cite>​http://​math.ucr.edu/​home/​baez/​week253.html</​cite>​
 </​blockquote>​ </​blockquote>​
 +
 +<​blockquote>​r. Correlation functions of local operators in
 +R1,3 depend only on the Lie algebra of the gauge group and are unaffected by global
 +issues such as the choice of Γ. This means that no current experiment can distinguish
 +between the four possibilities. Nonetheless,​ the physics in flat space can depend in
 +subtle ways on Γ (and in more dramatic ways when spacetime has interesting topology).
 +The purpose of this paper is to describe the crudest differences between the theories:
 +the spectrum of line operators and the periodicities of theta angles.<​cite>​https://​arxiv.org/​pdf/​1705.01853.pdf</​cite></​blockquote>​
  
 **A great discussion of these things with awesome illustrations can be found in section 1.4 and at page 26 in Some Elementary Gauge Theory Concepts by Hong-Mo Chan, Sheung Tsun Tsou:​** ​ **A great discussion of these things with awesome illustrations can be found in section 1.4 and at page 26 in Some Elementary Gauge Theory Concepts by Hong-Mo Chan, Sheung Tsun Tsou:​** ​
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 <-- <--
  
---> ​Questions ​left open by the standard model?#+--> ​What questions are left open by the standard model?#
  
 See [[:​open_problems|Open Problems]] See [[:​open_problems|Open Problems]]
  
    
 +<--
 +
 +--> What symmetries do exist in the standard model and what is their experimental status?#
 +see https://​physics.stackexchange.com/​questions/​97896/​symmetries-of-the-standard-model-exact-anomalous-spontaneously-broken
 <-- <--
 <tabbox History> ​ <tabbox History> ​
   * The Rise of the Standard Model: A History of Particle Physics from 1964 to 1979 by Lillian Hoddeson   * The Rise of the Standard Model: A History of Particle Physics from 1964 to 1979 by Lillian Hoddeson
   * Resource Letter: The Standard Model and Beyond by Jonathan L. Rosner   * Resource Letter: The Standard Model and Beyond by Jonathan L. Rosner
 +  * https://​inference-review.com/​article/​the-standard-model by Sheldon Glashow
 +
 </​tabbox>​ </​tabbox>​
  
  
models/standard_model.1522413314.txt.gz · Last modified: 2018/03/30 12:35 (external edit)