Tagged Questions
0
votes
0answers
40 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, $$ \mathcal{L} = \text{kinetic} +
...
4
votes
1answer
102 views
Mass gap for photons
I am puzzled by the answers to the question:
What is a mass gap?
There, Ron Maimon's answer gives a clear-cut definition, which I suppose applies to any quantum field theory with Hamiltonian $H$, ...
4
votes
1answer
97 views
Soft Mass and Physical Mass in Softly-broken SUSY
In softly broken SUSY, the bare mass parameters may be specified at e.g. the GUT scale, and then we can run these down to another scale using RGEs, similar in form to the RGEs for gauge couplings, ...
11
votes
3answers
476 views
The interpretation of mass in quantum field theories
Consider a free theory with one real scalar field:
$$
\mathcal{L}:=-\frac{1}{2}\partial _\mu \phi \partial ^\mu \phi -\frac{1}{2}m^2\phi ^2.
$$
We write this positive coefficient in front of $\phi ^2$ ...
2
votes
0answers
114 views
Do all the particles acquire mass in the Standard Model due to the Higgs mechanism only?
I know that a mass term for an intermediate boson is not compatible with the gauge symmetry. But in principle a mass term for the electron field does not violate a gauge symmetry. However to build an ...
1
vote
0answers
76 views
Glueball mass in non-abelian Yang Mills theory
How can the glueball mass be calculated in Yang Mills theory?
3
votes
2answers
305 views
What is the role of the vacuum expectation value in symmetry breaking and the generation of mass?
Consider a theory of one complex scalar field with the following Lagrangian.
$$
\mathcal{L}=\partial _\mu \phi ^*\partial ^\mu \phi +\mu ^2\phi ^*\phi -\frac{\lambda}{2}(\phi ^*\phi )^2.
$$
The ...
6
votes
3answers
261 views
What is the massless limit of massive electromagnetism?
Consider electromagnetism, an abelian gauge theory, with a massive photon. Is the massless limit equal to electromagnetism? What does it happen at the quantum level with the extra degree of freedom? ...
3
votes
3answers
148 views
Charge Analog of the Higgs Boson?
Since mass can be given to particles via the interaction with the Higgs Field could there be a "Charger Field" that supplies particles with charge? Possibly this would require two different "charger ...
1
vote
1answer
117 views
Lepton masses in the Standard Model
Some simple questions regarding leptonic masses in the Standard Model (SM):
Why there is not an explicit mass term in addition to the effective mass term that arises from the Yukawa terms after ...
5
votes
3answers
462 views
Why can't gauge bosons have mass?
Clearly, a mass term for a vector field would render the Lagrangian not gauge-invariant, but what are the consequences of this? Gauge invariance is supposed to be crucial for the renormalisation of a ...
4
votes
2answers
148 views
How can a pion have a mass, given it's a “field mediator” and created/destroyed continuously?
Maybe some of my assumptions here are basically wrong, but isn't it true that
pion is the "mediator" for the strong force field.
the quantum field theory basically says that there are no fields, ...
0
votes
1answer
153 views
How to calculate Rest Mass practically with Standard Model?
With relativistic physics, we can apply force to see resistance against acceleration. It'd give us relativistic mass and we have well established formula to get to the Rest Mass as long as we know the ...
3
votes
2answers
497 views
Does Dark Matter interact with Higgs Field?
Dark matter does have gravitational mass as we know from its discovery. Does it have inertial mass?
2
votes
1answer
471 views
What is the difference between pole and running mass?
For example, when we meassure Higgs boson mass to be 125 GeV, do we think about renormalized or pole mass? Should the mass of the Higgs change if it is produced at higher energies?
8
votes
4answers
2k views
Why don’t photons interact with the Higgs field?
Why don’t photons interact with the Higgs field and hence remain massless?
0
votes
2answers
205 views
What is the interaction with Higgs field(s) that give the quarks so much different masses?
The masses of quarks are:
mu 2∼3 MeV md 4∼6 MeV
mc 1.3 GeV ms 80∼130 MeV
mt 173 GeV mb 4∼5 GeV
3
votes
2answers
623 views
Why do neutrino oscillations imply nonzero neutrino masses?
Neutrinos can pass from one family to another (that is, change in taste) in a process known as neutrino oscillation. The oscillation between the different families occurs randomly, and the likelihood ...
11
votes
3answers
769 views
Decay of massless particles
We don't normally consider the possibility that massless particles could undergo radioactive decay. There are elementary arguments that make it sound implausible. (A bunch of the following is ...
4
votes
4answers
214 views
Massive particles and speed of their propagation
Can one show that in quantum field theory at least some example massive particles propagate with speed less than speed of light, while massless travel at speed of light? Well, motion is a different ...
5
votes
3answers
287 views
bound states of massless fields?
Question: are they mathematically possible at all? physically?
with finite mass systems, usually the binding energy contributes to the rest-mass of the system. It would seem that even if you could ...
3
votes
6answers
1k views
