Gauge and Lorentz invariance for Lagrangians

Click For Summary
SUMMARY

The discussion centers on the Lagrangian expression ##YHLN_{1}^{c} + Y^{c}H^{\dagger}L^{c}N_{1} + \text {h.c.}##, involving ##SU(2)## doublets ##L=(N_{0}, E')## and ##L^{c}=(E^{'c}, N_{0}^{c})##, along with neutral Majorana fermions ##N_{1}## and ##N_{1}^{c}##. Participants seek clarification on the multiplication of column vectors in the Lagrangian and the nature of the components of ##L##, ##L^{c}##, ##N_{1}##, and ##N_{1}^{c}##, specifically whether they are ##4##-component spinors. The discussion highlights the ambiguity in terminology regarding the classification of ##H## and ##L## as either column vectors or spinors.

PREREQUISITES
  • Understanding of Lagrangian mechanics in quantum field theory
  • Familiarity with ##SU(2)## representations and doublets
  • Knowledge of Majorana fermions and their properties
  • Basic concepts of spinors and their mathematical operations
NEXT STEPS
  • Research the mathematical operations involving column vectors in quantum field theory
  • Study the properties and implications of ##SU(2)## doublets in particle physics
  • Examine the role of Majorana fermions in supersymmetric theories
  • Explore references on Lagrangian formulations in supersymmetric systems
USEFUL FOR

The discussion is beneficial for theoretical physicists, particularly those specializing in quantum field theory, particle physics, and supersymmetry, as well as graduate students seeking to deepen their understanding of Lagrangian mechanics and fermionic fields.

spaghetti3451
Messages
1,311
Reaction score
31
Consider the following Lagrangian:

##YHLN_{1}^{c} + Y^{c}H^{\dagger}L^{c}N_{1} + \text {h.c.},##

where ##L=(N_{0}, E')## and ##L^{c} = (E^{'c}, N_{0}^{c})## are a pair of ##SU (2)## doublets and ##N_{1}## and ##N_{1}^{c}## are a pair of neutral Majorana fermions.

------------------------------------------------------------------------------------------------------------------------------------------------

1. In the first term, ##H## and ##L## are column vectors. How do you multiply two column vectors in the first term of the Lagrangian?

2. Are ##L## and ##L^{c}## ##4##-component spinors? Are ##N_{1}## and ##N_{1}^{c}## also ##4##-component spinors? How do the components of the vectors and spinors in the first term multiply?
 
Last edited:
Physics news on Phys.org
spaghetti3451 said:
Consider the following Lagrangian:

##YHLN_{1}^{c} + Y^{c}H^{\dagger}L^{c}N_{1} + \text {h.c.},##

where ##L=(N_{0}, E')## and ##L^{c} = (E^{'c}, N_{0}^{c})## are a pair of ##SU (2)## doublets and ##N_{1}## and ##N_{1}^{c}## are a pair of neutral Majorana fermions.

------------------------------------------------------------------------------------------------------------------------------------------------

1. In the first term, ##H## and ##L## are column vectors. How do you multiply two column vectors in the first term of the Lagrangian?

2. Are ##L## and ##L^{c}## ##4##-component spinors? Are ##N_{1}## and ##N_{1}^{c}## also ##4##-component spinors? How do the components of the vectors and spinors in the first term multiply?
Can you give a reference for this expression? Is it a supersymmetric system? I am not sure what you mean by "H and L are column vectors", it could mean SU(2) doublets or it could mean spinors. In either case, there is something that is not working so the original reference would be helpful.
 

Similar threads

  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
3
Views
1K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 0 ·
Replies
0
Views
2K
  • · Replies 49 ·
2
Replies
49
Views
7K
  • · Replies 0 ·
Replies
0
Views
1K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 38 ·
2
Replies
38
Views
5K