All Questions
11
questions
1
vote
0
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49
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Why does S-V or T-A couplings in Fermi weak interaction model produce electron oscillations?
In Fermi interaction model, vector bilinears were originally included in the interaction Lagrangian but since these couldn't explain nuclear spin changes other combinations were considered. However V-...
- 1,088
0
votes
0
answers
57
views
Classifying elementary fermions
Familiar elementary (non-composite) relativistic fermions are of the Dirac, Weyl, and Majorana kinds. Are there other kinds allowed in principle by relativistic quantum physics? If not, why not?
Are ...
- 11
7
votes
3
answers
961
views
Does the Pauli exclusion principle apply to one fermion and one antifermion?
I understand that two fermions cannot simultaneously have the same <momentum, spin> state. I know this is also true of two anti-fermions. But is it possible for one fermion and one anti-fermion ...
- 167
0
votes
0
answers
138
views
Calculating the residue as part of Matsubara summation
On page no. $166$ of "Many-body quantum theory in
condensed matter physics" by Henrik Bruus & Karsten Flensberg, while explaining the summation of Matsubara frequency, the following ...
- 405
5
votes
3
answers
797
views
Why are stable fundamental particles fermions?
Within the Standard Model, any particle decay eventually terminates at the same stable fundamental particles, i.e. u- and d-quarks, the electron and neutrinos (let's forget about neutrino oscillations ...
0
votes
0
answers
396
views
Propagator for fermion fields and Feynman diagrams
I need some help concerning the interpretation of propagators and Feynman diagrams.
The free fermion propagator is given by the contraction of two fields $\psi(x),\bar\psi(y)$:
$D_F(x-y)=T\{\psi(x)\...
- 263
5
votes
1
answer
405
views
Multi-Fermion interactions induced by integrating-out Yukawa-Higgs terms?
Suppose one considers a multi-component free fermions field theory with field $\psi_{q_i}$ with a give global symmetry (such as U(1)). We can say that every component of fermions carry some U(1) ...
- 299
5
votes
1
answer
711
views
Anomaly cancellation and fermion number violation
In the standard model, an axial $SU(3)$ currents has anomaly which after quantization leads to the fermion number violation. However, taking all the fermions into account we note that the anomalies ...
- 104
3
votes
1
answer
977
views
Complex masses for Dirac and Weyl spinors
I'm trying understand how to rotate Dirac fields to absorb complex phases in masses. I have a few related questions:
With Weyl spinors, I understand, $$ \mathcal{L} = \text{kinetic} +
|M|e^{i\...
- 15.2k
2
votes
2
answers
478
views
Fermion Field of Standard Model
Why fermion field is treated as anti-commuting and boson field as truly classical in standard model?
- 1,063
16
votes
3
answers
3k
views
What are the mathematical problems in introducing Spin 3/2 fermions?
Can the physics complications of introducing spin 3/2 Rarita-Schwinger matter be put in geometric (or other) terms readily accessible to a mathematician?
- 365