Higgs boson

[ajb]

I guess this is rather a philosophical question than a real physics/mathematics question.

 

If we assert that fundamental matter particles are always fermions and that forces are always mediated by bosons, or at least within the standard model, then should the Higgs be considered as matter or as a force?

 

My own through is that it is really neither and should be dealt with carefully when trying to assert matter <-> fermions and forces <-> bosons.

 

Then when we introduce supersymmetry the situation is even more mixed up, but lets not get ahead of ourselves.

 

So, do you think of the Higgs as matter or as a force, or as something else?

[mississippichem]

Being in chemistry, I never think much about bosons at all (except for the for photons though I never really have to deal with them directly, just the excitations they cause). I've always assumed what you stated, that bosons are forces and fermions are matter. I'm not too familiar with the Higgs Boson but it seems like an interesting philosophical question. Why would the Higgs Boson not be a force from your perspective ajb, as it is a boson?

[ajb]

Why would the Higgs Boson not be a force from your perspective ajb, as it is a boson?

 

The Higgs is a scalar boson and not vector boson. It cannot be understood in terms of a connection and so is not directly related to gauge symmetry, which is really the origin of the forces.

 

However, the Higgs can be understood in terms of a superconnection in the sense of Quillen.

[Dekan]

What I find hard to understand, is this:

 

Hasn't the Higgs been thought up, as a way to explain why particles exhibit a property we call "mass". According to the Higgs idea, this mass isn't a real, intrinsic property possessed by a particle. Mass is just a kind of resistance experienced by the particle, when the particle moves through the Higgs Field. Like a baseball experiences air resistance, when it moves through the air.

 

Is that right? If it is, then why do physicists who are trying to find the Higgs, keep speculating what the mass of the Higgs is?

 

I mean, if mass is only a kind of illusion caused by the Higgs, then how can the Higgs itself have any mass?

 

What causes the mass of the Higgs?

[timo]

For a conventional particle physicist the distinguishing feature of the gauge fields is that they are the result of keeping the action invariant under a local gauge transformation. Since that is not the case for the Higgs field I don't count it as a gauge field, which is the term I use almost synonymously with "force" (except that I don't use the term "force" at all unless I talk about "F=ma"). Some time ago I would have put the Higgs Boson under "something else", but today I tend to consider the Higgs Field a matter field just like the others, except that it happens to have a different spin. Susy seems to only strengthen that view since then the Higgs and the conventional matter superfields are even structurally equivalent (chiral multiplets - or at least I think they are), while the gauge fields are in a vector multiplet.

In most of physics (and its partner disciplines like chemistry, biology, ...) the characterizing feature of matter is its fermionic nature, since that is what allows to build up stable non-trivial structures. Calling the Higgs boson matter would violate this. But then the Higgs boson doesn't play a role in this kind of physics, anyways, so who cares what it's being counted as, then?

Edited July 30, 2011 by timo

[ajb]

...so who cares what it's being counted as, then?

 

I am not sure I really care myself

 

Other than typically one thinks of forces as being bosons and matter as being fermions, but the Higgs seems to go against this. Or really is it a hint that we need supersymmetry?

[timo]

I don't see having scalar particles and spinor particles in a theory as a hint that a spinorial superpartner is needed for each scalar (and vice versa). In principle, you can just write down scalar and fermionic field theories and quantize them, and I see no reason why everything should be explained by one of the two structures. The only reason I see for having spinors only is that they properly reflect the known matter particles. As said, I consider distinguishing gauge fields and matter appropriate (rather than gauge fields, matter, Higgs fields), but that is only a personal feeling of style.

 

Note also that the "chemist's definition" by which matter is the SM fermions and the structures containing them is not the only definition of matter being used. In astrophysics I've seen taking the relation of mass to typical kinetic energies as the criterion, i.e. particles with a mass much greater than their kinetic energy are matter, particles with a kinetic energy much greater than their mass are radiation (and approximated as massless for their contribution to the energy-momentum tensor). The German Wikipedia version defines matter as "everything object of observation in natural sciences that has mass" (dunny how they came up with that definition, but apart from bringing tears to the eyes of everyone knowing the SM it doesn't sound too unsensible).

[MigL]

The Higgs mechanism supposes the energy state of the vacuum is not at the zero level such that there is a potential energy of the vacuum ( permeates all the causally connected universe ). This potential energy is equivalent to a directionless or scalar field. Any quantum description of a field, wether scalar or vector, predicts the existence of virtual force carrier bosons. I am of the opinion that the Higgs particle would therefore be a boson.

 

Supersymmetry seems an un-needed complication of things.

Edited August 1, 2011 by MigL

[timo]

The Higgs mechanism supposes the energy state of the vacuum is not at the zero level such that there is a potential energy of the vacuum ( permeates all the causally connected universe ). This potential energy is equivalent to a directionless or scalar field. Any quantum description of a field, whether scalar or vector, predicts the existence of virtual force carrier bosons. I am of the opinion that the Higgs particle would therefore be a boson.

Are you really trying to argue that the Higgs boson is a boson or was that a typo? And why would "any quantum description of a field, whether scalar or vector, predict the existence of virtual force carrier bosons"?

[bombus]

I don't believe they actually exist at all, apart from as concepts created by the human mind. I think all particle physics is the same as stating that within a block of marble there exists a face, and then carving out a face and saying 'see, I told you so'. This does not mean that their 'discovery' cannot be put to good use however, just that it will not really bring us any closer to 'the underlying truth' as I am beginning to think that there is no 'underlying truth' that exists without subjectivity.

[ajb]

Any quantum description of a field, wether scalar or vector, predicts the existence of virtual force carrier bosons.

 

Not necessarily, one can construct theories that use exchange fermions. It turns out that these do not have the correct properties to be realised as the forces we see around us.

 

Our current understanding is that forces are due to gauge symmetry. I think that understanding exchange fermions in this way would be difficult, but we do have superconnections to play with. Maybe one could understand exchange fermions geometrically in this way.

 

 

I am of the opinion that the Higgs particle would therefore be a boson.

 

In a conventional gauge theory the symmetries are all bosonic in nature and then when you spontaneously break some of these symmetries the resulting Goldstone particles are bosons.

 

When you consider a fermionic symmetry, such as those in supersymmetric theories the resulting Goldstone particles are fermions.

 

So we can have both Goldstone bosons and fermions.

 

You are right, as the electroweak symmetry is bosonic in nature then the resulting Goldstone particles will be bosons.

 

Supersymmetry seems an un-needed complication of things.

 

Supersymmetry does have some merits, but mostly these are technical and help out with the calculations. To date there is no creditable evidence of supersymmetry. My suggestions that a bosonic scalar in nature should be a hint at supersymmetry should be taken "tongue in cheek", though supersymmetry and the Higgs boson may well be related. In particular the MSSM has the mass of the Higgs as a prediction, where the standard model has it as a parameter.

[36grit]

Maybe it's like asking whether or not an atom is energy or a particle? e=mc-square and we know that it is energy, but from our perspective it is a particle. What is the dividing factor? The speed of light seems to be the dividing factor between the field/particle ratio, which will vary according to the field expansion plane of the viewer or of the viewing instrument.

My current view of realty is this: expansion rate divided by the speed of light equals energy potential. Energy potential is the particle, or the energy "left over" after the expansion of its given field. The boson is the particle of it's force field that governs the intensity and actions of it's force plane.

My views are governed more by the particles of an artistic plane than a mathmaticle plane but they are related within the complex structre that exists within the hierarchy of planes.

 

 

[MigL]

I don't have a clear understanding of Goldstone particles, other than they can manifest themselves as Higgs particles in some cases and combination particles in others. I always assumed these combination particles were bosonic in nature and not fermionic.

 

I have a certain 'confort' with the Higgs field although its resistance to accelerating motion and not constant motion ( and as such giving rise to inertial mass ) is puzzling. Not so much with the Higgs particle. The fields that I've considered are QED and QCD which both give rise to force carrier bosons. Is it possible that the scalar Higgs field does not produce either force carrying bosons or fermions ??

[alpha2cen]

How can we explain mass to energy conversion by using Higgs Boson concept? At the nuclear fission or fusion reaction mass defect occurs. Can we describe a mass conversion to energy by using Higgs concept?

[alpha2cen]

How can we describe proton anti-proton annihilation reaction? At the annihilation reaction space, mass and particles are disappearing, only energy are left.

[timo]

How can we describe proton anti-proton annihilation reaction? At the annihilation reaction space, mass and particles are disappearing, only energy are left.

That's wrong. One of the largest physics experiments in the world (Tevatron) essentially does nothing else than colliding protons and antiprotons, and they do see quite a lot more than only energy being left. You seem to be incorrectly extrapolating the statement that electrons and positrons annihilate into pure energy (which is already wrong by itself) to "therefore every matter<->antimatter pair does the same".

To answer your question: Proton-antiproton reactions are explained via the Standard Model of particle physics plus a lot of phenomenological tricks for the description of non-elementary particles. At least at very high energies you consider the quarks and gluons in the proton (their amount is obtained from fitting a curve to measurement data) as being pretty much free particles and describe the core of the process with perturbative Standard Model physics. Thereafter, some corrections are applied, but these are very tricky, and I think only few people (excluding me) understand these properly.

[alpha2cen]

That's wrong. One of the largest physics experiments in the world (Tevatron) essentially does nothing else than colliding protons and antiprotons, and they do see quite a lot more than only energy being left. You seem to be incorrectly extrapolating the statement that electrons and positrons annihilate into pure energy (which is already wrong by itself) to "therefore every matter<->antimatter pair does the same".

To answer your question: Proton-antiproton reactions are explained via the Standard Model of particle physics plus a lot of phenomenological tricks for the description of non-elementary particles. At least at very high energies you consider the quarks and gluons in the proton (their amount is obtained from fitting a curve to measurement data) as being pretty much free particles and describe the core of the process with perturbative Standard Model physics. Thereafter, some corrections are applied, but these are very tricky, and I think only few people (excluding me) understand these properly.

 

The annihilation is not high speed and high energy collision. It is simple proton--anti-proton attraction by electromagnetic force, and then proton -- anti-proton attachment by strong force, and finally annihilation reaction.

If remaining energy is too high, electron- positron annihilation reaction will be suitable to describe mass, space and particle disappearing.

[timo]

There are times that I feel that I am having a conversation with a random text generator.

[36grit]

Here's a nice article: http://news.discovery.com/space/what-has-the-tevatron-really-discovered-110407.html

relative to the disscution.

[Dave World]

I guess this is rather a philosophical question than a real physics/mathematics question.

 

If we assert that fundamental matter particles are always fermions and that forces are always mediated by bosons, or at least within the standard model, then should the Higgs be considered as matter or as a force?

 

My own through is that it is really neither and should be dealt with carefully when trying to assert matter <-> fermions and forces <-> bosons.

 

Then when we introduce supersymmetry the situation is even more mixed up, but lets not get ahead of ourselves.

 

So, do you think of the Higgs as matter or as a force, or as something else?

 

Something else. Stay tuned.

[MigL]

The theory predicts the Higgs particle to have a mass of 250 GeV, equivalent to Weak scale energy ( not 150 GeV where the blue peak is located ). It absolutely must have this mass to acccount for the masses of the electron and quarks.

 

However, quantum contributions within the existing standard model, tend to raise this mass to Plank scale energies, roughly 16 orders of magnitude higher. Quantum contributions are comparable to an object moving through a viscous fluid where we cannot use just the object to calculate forces, but must take into account an appreciable amount of the surrounding fluid entrained in the object's motion, the boundary layer if you will. Faynman ( along with Wigner and Tomanaga, spelling ???) used this method to originally formulate the virtual particle contributions to QED, and it was later put into a rigorous framework by Wilson in re-normalization theory. This obviously leads to a problem for the Higgs particle.

 

It turns out that if you invoke supersymmetry, ie every 1/2 spin fermion has a unit spin boson counterpart and vice-versa, then the quantum contributions will cancel ( or nearly cancel depending on the weights of the supersymmetric partners). The fact that no supersymmetric particles have ever been found indicates that their masses are rather high for our present colliders. In effect both the Higgs particle and the supersymmetry particles must have masses of several hundred GeV or even 1000 or more GeV.

 

This then involves another spontaneous symmetry breaking to account for the differing masses of fermions and bosons compared to their supersymmetric partners, and I don't recall the details too well, but this leads to excessive flavour change in quarks.

 

It just seems a little too convoluted for my liking ( as if the universe gives a damn what I think )

[ajb]

The theory predicts the Higgs particle to have a mass of 250 GeV, equivalent to Weak scale energy ( not 150 GeV where the blue peak is located ). It absolutely must have this mass to acccount for the masses of the electron and quarks.

 

Lets be a little careful here. The standard model of particle physics does not predict the mass of the Higgs boson, rather you have to put it in as a parameter. This you can then place bounds on based on phenomenology. The minimal supersymmetric standard model predicts the mass based on the possible couplings. In the MSSM the Higgs mass cannot be made into a free parameter.

 

 

However, quantum contributions within the existing standard model, tend to raise this mass to Plank scale energies, roughly 16 orders of magnitude higher.

 

So this is the hierarchy problem. Quantum effects should push the Higgs mass towards the Planck mass. However, this is assuming there is no symmetry to protect the Higgs mass. This is the case for the standard model, but adding supersymmetry cures this, as you point out...

 

 

It turns out that if you invoke supersymmetry, ie every 1/2 spin fermion has a unit spin boson counterpart and vice-versa, then the quantum contributions will cancel ( or nearly cancel depending on the weights of the supersymmetric partners).

 

The fact that no supersymmetric particles have ever been found indicates that their masses are rather high for our present colliders. In effect both the Higgs particle and the supersymmetry particles must have masses of several hundred GeV or even 1000 or more GeV.

 

This then involves another spontaneous symmetry breaking to account for the differing masses of fermions and bosons compared to their supersymmetric partners, and I don't recall the details too well, but this leads to excessive flavour change in quarks.

 

Right, in a theory that is supersymmetric the masses of the partner bosons and fermions is equal. As we see no evidence of such a pairing supersymmetry cannot be exactly realised in nature. The supersymmetry must be broken and this requires the mass of the sparticles (the superpartners) to be greater than the particles.

 

Something else. Stay tuned.

 

 

This sounds like you something specific in mind. Care to share?

[Amr Morsi]

Points pointed to in the thread:

 

1. Higgs: matter, a special mediator, both or something else / neither ....... or something else.

2. Has it checked experimentally that electrons and positrons annihilate to pure energy?

3. Are they real or virtual? AND, if real, has it been discovered experimentally or not?

 

 

A good question, perhaps it was in ajb's head, or a similar If real, why not be considered as a particle?

 

Thanks to add any.

[ajb]

1. Higgs: matter, a special mediator, both or something else / neither ....... or something else.

 

Indeed this basically my opening question. I think it is rather philosophical than of any real importance to physics.

 

2. Has it checked experimentally that electrons and positrons annihilate to pure energy?

 

Electron and positron annihilation results in two photons. Electron-positron collisions can result in jets.

 

3. Are they real or virtual? AND, if real, has it been discovered experimentally or not?

 

They can be real or virtual, so either as internal or external states in Feynman diagrams.

 

I think it will take a while before the discovery of the Higgs, assuming it exists, is made official and any controversy to die down. It will take a lot of analysis of the data before one can say for definite.

[Farsight]

I guess this is rather a philosophical question than a real physics/mathematics question.

 

If we assert that fundamental matter particles are always fermions and that forces are always mediated by bosons, or at least within the standard model, then should the Higgs be considered as matter or as a force?

 

My own through is that it is really neither and should be dealt with carefully when trying to assert matter <-> fermions and forces <-> bosons.

 

Then when we introduce supersymmetry the situation is even more mixed up, but lets not get ahead of ourselves.

 

So, do you think of the Higgs as matter or as a force, or as something else?

Something else. I take my cue from A Zeptospace Odyssey: A Journey into the Physics of the LHC by Gian Francesco Giudice. He's a physicist at CERN with a hundred-plus papers to his name. He talks about the Higgs sector on pages 173 through 175. If you don't have this book you can find it on amazon and do a search-inside on "Higgs sector". He starts by saying: “The most inappropriate name ever given to the Higgs boson is 'The God particle'. The name gives the impression that the Higgs boson is the central particle of the Standard Model, governing its structure. But this is very far from the truth.”

 

On page 174 he says: “Unlike the rest of the theory, the Higgs sector is rather arbitrary, and its form is not dictated by any deep fundamental principle. For this reason its structure looks frighteningly ad-hoc". He also says "It is sometimes said that the discovery of the Higgs boson will explain the mystery of the origin of mass. This statement requires a good deal of qualification.”

 

He gives a good explanation, and finishes by saying: “In summary, the Higgs mechanism accounts for about 1 per cent of the mass of ordinary matter, and for only 0.2 per cent of the mass of the universe. This is not nearly enough to justify the claim of explaining the origin of mass.”

 

As for SUSY, see Reality check at the LHC.