All Questions
Tagged with quantum-field-theory particle-physics
1,059
questions
-1
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2
answers
124
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Could polaroid filters with somewhat strange properties violate Bell's inequality without non-locality?
Imagine a world where polaroid filters have somewhat strange properties, in such a way that this is impossible or very hard to know. The inhabitants use polaroid filters to determine what polarization ...
- 15
0
votes
1
answer
106
views
Does every field correspond to a particle?
I know that particles in QFT are just excitations of its corresponding field. But is it possible to have a field which cannot generate particles?
If yes, what terms must be added to the Lagrangian so ...
- 1,611
-2
votes
1
answer
49
views
Do particles, quarks, atoms really move in space, or is it field disturbance-wave that moves in S-T with speed $c$? How particles move in S-T in QFT? [closed]
As I understand particles are localized fields (16fields+g). Can you explain on hydrogen atom example that moves in space vacuum. Does it really moving, or it is continious field disturbance ...
- 3
-1
votes
1
answer
50
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Electron Interference when produced by $W$ boson
Hi I was wondering about the following setup. Let’s say we have a radioactive atom which decays via beta decay which produces a $W$ boson. The $W$ boson has a chance of turning into an electron or a ...
- 133
11
votes
2
answers
2k
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Feynman diagrams vs old fashioned peturbation theory (OFPT) vs reality
As far as I understand, our best picture of the world is that it is comprised of universe-spanning fields (one for each type of particle) that can interact with each other. The interactions are local, ...
- 525
0
votes
0
answers
41
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General matrix element in weak interaction
During my studies on weak interactions and $\beta$-decay, I've to study how theory and experimental results bring us to achieve the V-A structure of weak vertices. My doubts regard the theory.
Suppose ...
- 361
1
vote
0
answers
71
views
What is intrinsic parity? Why is negative intrinsic parity possible?
What is intrinsic parity? It seems that it is a concept only for relativistic quantum physics. Why is it not relevant for non-relativistic quantum mechanics?
- 1,045
13
votes
1
answer
2k
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How does one describe individual particles in QFT in practice?
A similar question was posted on this site at least ten times, but not quite in this formulation, and with no satisfactory answers, so I give it another try.
Quantum field theory textbooks almost ...
- 290
0
votes
2
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122
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What symmetry present in a low energy theory is broken or not exact at high energies?
The opposite is quite common such as EWSB, SUSY or GUT. Is there any example where a certain symmetry emerges from a low energy effective theory but is not present in the high energy theory?
- 195
0
votes
1
answer
81
views
What advantages might the Circular Electron-Positron Collider have over the Compact Linear Collider?
Despite Chen-Ning Yang's objections, the Circular Electron Positron Collider (CEPC) project is progressing. The CEPC research team officially released its Technical Design Report (TDR) for the ...
- 619
2
votes
0
answers
24
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Why is there an infinite supply of energy in slow-roll inflation?
The physical model of inflation includes a metastable false vacuum, or a slow-roll field on a flat potential. In either case, I just realized how this is completely insane. With the exponential growth ...
- 619
1
vote
3
answers
145
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Why doesn't frozen-out dark matter annihilate later during structure formation?
The so-called freeze-out of dark matter is based on a homogeneous description. However, in the later stages of the universe, where structures form, it seems very likely that the reaction rate would ...
- 619
1
vote
0
answers
52
views
What is the difference between the center of mass energy of partons, and the invariant mass of the particles after a collision?
In a paper about the Atlas experiment (https://arxiv.org/abs/2103.01918) differential cross sections of $pp→ZZ→4\ell$
are being presented. However these cross-sections are functions of the invariant ...
- 172
0
votes
0
answers
47
views
Why are the expressions of the Skyrme Model related with a kinetic and a mass term?
I was reading about the Syrme Model Lagrangian,
$$
\mathcal{L} =-f^2_\pi/4 Tr(L_\mu L^\mu) + 1/32e^2 Tr([L_\mu,L_\nu]^2)- \frac{\mu^2}{2} Tr(1-U)
$$
where $L_\mu=U^\dagger \partial_\mu U$. I've read ...
- 161
1
vote
1
answer
72
views
Inconsistency in the $2\to 2$ kinematics
I must be confusing something horribly, because this should be very simple, but I am keep getting inconsistent results in the basic 2->2 scattering kinematics.
Let the process be $$a(p_1) + b(p_2) \...
- 857