Higgs field, mass and why particles cling to it?

[Sorry!]

didn't know where to post this. Was wondering earlier why objects have mass so i googled it.. I'm in grade 12 so don't really understand EVERYTHING you know lol.

but anyways found out about higgs field and higgs boson. Can someone explain how this explains why things have 'mass' like why do particles cling to it (the higgs boson) and how does this cause drag to create the mass.

 

[stevebd1]

I always thought the link below was a good introduction to the Higgs mechanism.

http://www.phy.uct.ac.za/courses/phy400w/particle/higgs5.htm

regards
Steve

 

[malawi_glenn]

also, Higgs only explains the mass of the W and Z bosons. See the sub-forum "High Energy, Nuclear, Particle Physics", there are many threads about LHC and Higgs mechanism etc.

 

[americanforest]

also, Higgs only explains the mass of the W and Z bosons. See the sub-forum "High Energy, Nuclear, Particle Physics", there are many threads about LHC and Higgs mechanism etc.

I understand it this way: Three components of the Higgs field create Electroweak Symmetry breaking and the quanta of the fourth component, the Higgs Boson gives, mass to all other fermions.

 

[Sorry!]

ohhh got you kind of makes more sense :D thks guys. i'll check out that article as well :D

 

[malawi_glenn]

I understand it this way: Three components of the Higgs field create Electroweak Symmetry breaking and the quanta of the fourth component, the Higgs Boson gives, mass to all other fermions.

I have never herd anyone else saying this...
reference?

 

[Barmecides]

I understand it this way: Three components of the Higgs field create Electroweak Symmetry breaking

I would rather say the opposite. During EW symmetry breaking, 3 components of the Higgs doublet (the goldstone bosons) are eaten by W and B fields resulting in massive W and Z.

and the quanta of the fourth component, the Higgs Boson gives, mass to all other fermions.

Yes, the vacuum expectation value (vev) through yukawa terms added by hand gives mass to fermions.
So on one side these terms are added by hand.
On the other side, we cannot easily add terms like m_i e_L e_R without breaking gauge invariance.

 

[stevebd1]

Below is an extract from a (very) basic summary I put together some time ago regarding fermions and bosons and the Higgs mechanism-

Fermions and bosons

Informally speaking, fermions are 'stiff' and are considered to be particles of matter while bosons are considered to be carriers of the fundamental forces. Bosons have integer spin while fermions have half-integer spin. Bosons can share quantum states while fermions are constrained by the Pauli exclusion principle* and cannot.

- Fermions
As an observer circles a fermion, the wave function changes, hence the term half-integer spin (1/2, 3/2, 5/2). Fermions have an antisymmetric wavefunction and show destructive interference of identical single particle wavefunctions, hence the inability to share quantum states.
Fermions fall into 2 types, quarks (that make up protons, neutrons) and leptons (electrons, muons).

- Bosons
As an observer circles a boson, the wave function doesn't change, hence the term integer spin (0,1,2). Bosons have a symmetric wavefunction and show constructive interference of identical particle wavefunctions, hence the ability to share quantum states.
Bosons fall into 2 categories-
- gauge (or vector) bosons- which are considered elementary particles, carriers of the fundamental forces- photons (electromagnetism), W and Z bosons (weak force) and gluons (strong force).
- composite particle bosons- which include He-4 atoms (Helium with 2 protons, 2 neutrons, 2 electrons), sodium-23 atoms (11 protons, 12 neutrons, 11 electrons) and the nucleus of deuterium (1 proton, 1 neutron). These are made up of an even number of fermions (composites with an even number of fermions become bosons, while composites with an odd number of fermions remain as fermions).


There is also the Higgs boson (yet to be detected), which make up the quanta of the Higgs field. The Higgs field supposedly permeates all of space with an ocean-like ether, which has 'grain' (like that of wood) that interacts with all other particles in 3 ways (2 types for bosons, 1 type for fermions)
- photon bosons travel with the grain and are therefore light and long range.
- W & Z bosons travel 'against' the grain and are heavy and short range.
- fermions travel 'through' the grain (such as electrons and quarks which 'tumble' through the Higgs field, making them appear as matter).
The idea of grain should not be thought of as a direction in 3-dimensional space but as an abstract internal space occupied by vector bosons, quarks and electrons.


* Pauli exclusion principle, no two identical particles in a system, such as electrons or quarks can possesses an identical set of quantum numbers.


Steve

 

[curiousOne]

I'll follow up with a seemingly dumb question here:
If the Higgs boson is the quanta for the Higgs field, and the Higgs Boson can't go faster than light, then why is a black hole even possible ?
Shouldn't the Higgs boson follow the same rules as other bosons and end up 'locked' inside the black hole ?

 

[Ruslan_Sharipov]

Some references

http://arxiv.org/abs/hep-ph/0703001"
http://arxiv.org/abs/math/0605709"

 

[stevebd1]

For anyone interested, below is a link to a video of Peter Higgs talking about the Higgs mechanism-



Steve

 

[curiousOne]

Well, still no answer on my question. Doesn't anyone see a paradox here ?
So the higgs is a particle when it's outside the black hole so it can give mass to stuff around the black hole but somehow inside, it's no longer a particle, because that's not convenient.
I'm no genius but this seems ambiguous.

 

[humanino]

Well, still no answer on my question. Doesn't anyone see a paradox here ?
So the higgs is a particle when it's outside the black hole so it can give mass to stuff around the black hole but somehow inside, it's no longer a particle, because that's not convenient.
I'm no genius but this seems ambiguous.

Do you agree that from the point of view of general relativity, there is no real paradox of "how does gravity escape a black hole ?" ?

So you are asking a question relevant in the context of quantum mechanics really. Two things :

• If you are talking about "normal mass", the Higgs is almost irrelevant. Normal mass, yours and the one of objects around you is not explained by the Higgs anyway.
• If more generally you are concerned about how anything can escape a black hole, information and in particular the photons letting you know there is charge inside and/or the gravitons letting you know there is mass and (possibly) angular momentum, or even the Hawking radiation simply, leading eventually to the complete evaporation of the black hole, no fully satisfactory answer is available as of today, since we don't know what quantum gravity is.

But we can provide you with some answers, especially you can read Beaz's stuff on virtual particles, where you can find answers to such questions as "do virtual particles travel faster than light ?" or "do they contradict relativity or causality".

 

[Sojourner01]

So the higgs is a particle when it's outside the black hole so it can give mass to stuff around the black hole but somehow inside, it's no longer a particle, because that's not convenient.
I'm no genius but this seems ambiguous.

If I understand your question correctly: Higgs particles 'give' other particles mass. They don't []transmit[/i] gravitational force. It's a fallacy to assume that the two have to be the same thing. One assumes that the interaction between mass terms is quite separate from the process that they originate from.

 

[humanino]

If I understand your question correctly: Higgs particles 'give' other particles mass. They don't []transmit[/i] gravitational force. It's a fallacy to assume that the two have to be the same thing. One assumes that the interaction between mass terms is quite separate from the process that they originate from.

Once again : the Higgs boson is irrelevant to explain 99.99% of the mass we are talking about here. Normal mass around you does not come from the Higgs boson.

If you want to talk about dark matter or something like that, please state it explicitely.

 

[humanino]

somehow inside, it's no longer a particle, because that's not convenient.

BTW I did not pay enough attention to that. If someone tells you things about what is happening inside a black hole, you might as well tell him this is not science. Nobody knows what is happening behind the horizon. The horizon itself is not very special, and we don't expect that physics changes when we cross it, but we can't know.

So if I'm telling you that behind the horizon, the mass of particles is not explained by the Higgs boson or by the glue field, by nothing except little green Witten dwarfs, you can't prove me wrong.

 

[humanino]

http://arxiv.org/abs/hep-ph/0703001"
http://arxiv.org/abs/math/0605709"

Have those been published somewhere ?

 

[George Jones]

by the Higgs boson or by the glue field, by nothing except little green Witten dwarfs,

These things aren't the same?

 

[Jim Kata]

Alright, I'm just going to hijack this thread to ask my question about the Higgs. I know it is due to a degenerate vacuum basically U|0> does not equal |0>. Could someone clearly explain multiple or degenerate vacuum states. Also, kind of related or maybe not, I was listening to a talk by Wald on QFT in curved spacetime and he said there is no way to define a unique vacuum even in the free particle case. He said this was due to a lack of time translation symmetry, so you couldn't construct a Fock space. Could someone elaborate on this and more generally on why can't construct a Fock space even for non interacting quantum gravity.

 

[Pythagorean]

If you are talking about "normal mass", the Higgs is almost irrelevant. Normal mass, yours and the one of objects around you is not explained by the Higgs anyway.

you and the http://math.ucr.edu/home/baez/physics/Quantum/virtual_particles.html" you referenced both do this to me:

Furthermore, it is not at all clear that it will be useful to think of gravitational "forces," such as the one that sticks you to the Earth's surface, as mediated by virtual gravitons. The notion of virtual particles mediating static forces comes from perturbation theory, and if there is one thing we know about quantum gravity, it's that the usual way of doing perturbation theory doesn't work.

you and the author seem to stop just short of denying that the Higgs Field has anything to do with our experiential mass. I've nearly completed undergraduate studies in physics and I don't think I'll see particle physics (beyond Griffith's QM) until grad school, so without further ado... specific questions:

1) Are these two (gravity and gravity) completely different mechanisms that just happen to share the same name?
2) Are these the same mechanism but in a different situation (i.e. different particles, same 'operator')?

and a possibly off-topic question

3) is what we experience as inertia described in particle physics at all?

 

[humanino]

you and the author seem to stop just short of denying that the Higgs Field has anything to do with our experiential mass.

I tried to make it clear, but maybe I failed if you feel I stopped short. The Higgs field has nothing to do with our experiential mass. The Higgs mass is a missing piece of the standard model, linked to the electroweak sector. Even if quarks were massless in that (Higgs) sens, they would still have a (fairly) high constituent mass (300 MeV) inside your protons and neutrons. This is what makes you experiential mass. The mechanism producing this mass is far more interesting than the Higgs boson. It is a well defined mathematical problem with so many ramifications to such a depth that the Clay mathematical institute has put it as one of the "Millenium problems" with 1M$ prize.

Sorry if I can't answer the rest of your questions right now, but it would help if you could clarify them.

 

[curiousOne]

Thanks humanino. I think you've definitely explained plenty here for me to chew on.
Clearly, I don't know half of what I should. Time to go back to the books now...

 

[Barmecides]

I tried to make it clear, but maybe I failed if you feel I stopped short. The Higgs field has nothing to do with our experiential mass. The Higgs mass is a missing piece of the standard model, linked to the electroweak sector. Even if quarks were massless in that (Higgs) sens, they would still have a (fairly) high constituent mass (300 MeV) inside your protons and neutrons. This is what makes you experiential mass. The mechanism producing this mass is far more interesting than the Higgs boson. It is a well defined mathematical problem with so many ramifications to such a depth that the Clay mathematical institute has put it as one of the "Millenium problems" with 1M$ prize.

Sorry if I can't answer the rest of your questions right now, but it would help if you could clarify them.

Hello humanino,

I have a question about this topic. If quarks were massless (gedanken experiment), then wouldn't pions be massless (goldstone bosons) ?
Thas would mean in that case we would have a composite massless particle which is not so common in our present knowledge of the world ?

 

[Pythagorean]

Sorry if I can't answer the rest of your questions right now, but it would help if you could clarify them.

I'm in your debt for taking the time to answer them, no apology necessary.

I guess what I'm wondering is do constituent mass and the mass imparted by the Higg's Field follow the same exact law of gravity?

And as an addendum, I was wondering if it's known where inertia fits; (i.e. if there's a separate particle proposed to be responsible for inertia, or if inertia is some consequence of conventional gravity)

 

[Sojourner01]

Once again : the Higgs boson is irrelevant to explain 99.99% of the mass we are talking about here. Normal mass around you does not come from the Higgs boson.

I was stating this in the context of what the Higgs does, as opposed to what the Higgs does not - the point being that being responsible for certain mass terms in certain particle interactions does not in any way imply that the Higgs is responsible for transmitting the gravitational force; and still would not even if the Higgs was the origin of all mass. Therefore, invoking bits of theory about the Higgs in reference to the dynamics of black holes is not valid, because they aren't the gravitational force carriers.

I would point out that in discussions such as this, it helps to give a person benefit of the doubt when reading their opinion; just because you (collective) haven't interpreted what they were saying correctly, doesn't mean what they said was wrong. Drawing common-speech analogies in theoretical physics is fiendishly difficult and requires some suspension of disbelief if the point is to be communicated. For example:

If you want to talk about dark matter or something like that, please state it explicitely.

I never said any such thing. Nor did I contradict anything humanino said. The idea I intended to communicate is perfectly clear when one reads what I posted, and not what one wishes to see.

 

[humanino]

I have a question about this topic. If quarks were massless (gedanken experiment), then wouldn't pions be massless (goldstone bosons) ?

yes of course, everybody agrees that pions would be exact Goldstone bosons in that case. In fact, we would have tons of problems if the quarks were exactly masselss, already in QED BTW.

Thas would mean in that case we would have a composite massless particle which is not so common in our present knowledge of the world ?

I gave up making a list of all the conceptual problems that would lead to.

 

[humanino]

I guess what I'm wondering is do constituent mass and the mass imparted by the Higg's Field follow the same exact law of gravity?

And as an addendum, I was wondering if it's known where inertia fits; (i.e. if there's a separate particle proposed to be responsible for inertia, or if inertia is some consequence of conventional gravity)

You may want to review classical mechanics in the lagrangian formulation. Classical mechanics is the limit of quantum mechanics when the action involved is large compared to Planck's constant. Quantum mechanics follows from the non-relativistic limit of quantum field theory. This is a bit sketchy but should indicate you that we do have inertia in the standard model.

The fact that inertial mass and gravitational mass are the same is one of the basic assumptions of general relativity and can be considered valid as we have no experimental hint that it might not hold. Gravitation however is not addressed in the standard model.

Doksh_itzer has dubbed quarks INFOs, for (well) identified non-flying objects. They are probably far more interesting than UFOs, but being confined the question of their mass is quite a tricky one. There are entire books devoted to this issue. The "constituent mass" interpretation lies far remotely from gravitational problems. It is an effective mass, the kind of arising for instance to describe electrons moving in a ion lattice : their propagation undergoes constant random scattering resulting in an apparent mass larger than the free mass. As you can guess, there is a rigourous formalism behind, giving this effective mass the interpretation of an (effective) inertial mass. I am not quite sure what to comment about the corresponding (effective ?) gravitational mass however. It seems at first glance to me that those kinds of gravitational and effective mass should also be the same, because what really happens is that you want to replace a light mass with a fluctuating high momentum by a larger mass and a lower (more or less) constant momentum. Needs more thoughts though...

 

[kdv]

You may want to review classical mechanics in the lagrangian formulation. Classical mechanics is the limit of quantum mechanics when the action involved is large compared to Planck's constant. Quantum mechanics follows from the non-relativistic limit of quantum field theory. ...

Do you have a reference for that? where sonmeone starts from QFT and shows clearly how one recovers quantum mechanics by taking a well defined non-relativistic limit? I know that this is what one expects but I have never seen it done explicitly.

 

[Pythagorean]

Thank you for a well-rounded answer. I remember a bit of the Lagrangian stuff we did for generalized coordinates. Very impressive technique.

It is an effective mass, the kind of arising for instance to describe electrons moving in a ion lattice : their propagation undergoes constant random scattering resulting in an apparent mass larger than the free mass.

I took Solid State, and I remember this arising. This sort of implied to me that the actual mass of the object wasn't changing, and that it was a convenient math trick.

I must admit though, that a lot of Solid State went over my head. I took it before I took quantum or thermo, and Kittel didn't seem to match the lectures that great. Some of the homework problems didn't seem to have any development in the text either, so I could be far off in my perspective of effective mass in electrons/phonon interactions (that it is a mathematical trick and not physically true).

 

[humanino]

Do you have a reference for that? where sonmeone starts from QFT and shows clearly how one recovers quantum mechanics by taking a well defined non-relativistic limit? I know that this is what one expects but I have never seen it done explicitly.

These kind of things are usually not done in introductory textbooks, since they are more relevant to research programs really. Full blown calculation wavefunctions are kind of hairy, but tractable as you can guess from Baez's stuff on virtual particles.

However, you can find many references, even on this forum ! (see [thread=124893]this thread[/thread] for instance, with plenty of excellent references, especially from nrqed who has not been around for a few months apparently).

In addition, I'm sure condensed matter people would have more references.