Higgs field popular descriptions

[WaveHarmony]

With the recent announcement at Cern there have been many video clips published describing the Higgs field. They show heavy and light particles passing through a field and the commentary says that the effect of the field is to slow down particles and thus give them mass. The Higgs field supposedly permeates empty space. As we know particles traveling through empty space continue with constant velocity and momentum. The Higgs field description suggests that particles traveling through the Higgs field are slowed so the more they travel through the Higgs field the more they should be slowed down. The Higgs field theory seems to be inconsistent with observation. Can anyone explain?

Regards
WaveHarmony

 

[Drakkith]

How is it inconsistent with observations?

 

[WaveHarmony]

Well, the popular descriptions suggest that the Higgs field slows down particles. Particles in empty space will continue in a state of uniform motion without being slowed.
WaveHarmony

 

[Bill_K]

WaveHarmony, The Higgs field is (partially) responsible for particle masses, but the popular description that it "slows them down" is quite misleading. Especially, it does not mean that they get slower and slower and eventually come to a stop, like traveling through a jar of molasses!

 

[darkside00]

yeah, I think Physicists need to 'dumb it down' for the layman to help explain their mathematics and particle observations.

 

[haael]

I can be easily explained by saying that the Higgs field couples to the particle's acceleration. A particle indeed is being slowed down, but the opposing force is proportional to its acceleration.

 

[Drakkith]

yeah, I think Physicists need to 'dumb it down' for the layman to help explain their mathematics and particle observations.

This is much harder than one might think. Things almost always get lost in the analogies. How would anyone describe the interaction of subatomic particles with a field when your target audience doesn't even know what a subatomic particle is. Or what an atom is for that matter. Or what a field means in science.

It's comparable to me explaining a championship winning play in american football when you've never even seen a game before and I'm not allowed to explain the basic rules first.

 

[Drakkith]

I can be easily explained by saying that the Higgs field couples to the particle's acceleration. A particle indeed is being slowed down, but the opposing force is proportional to its acceleration.

But you cannot word it like this, it is incorrect. The particle is not being "slowed down", that is a reduction in velocity. It has resistance to acceleration, which we already have a term for, inertia, which is interconnected to mass.

This is exactly the case I was referring to in my above post. It's much more difficult than one might think to correctly describe theories in science without using scientific vocabulary and math. The Balloon Analogy for cosmology is another perfect example.

 

[darkside00]

This is much harder than one might think. Things almost always get lost in the analogies. How would anyone describe the interaction of subatomic particles with a field when your target audience doesn't even know what a subatomic particle is. Or what an atom is for that matter. Or what a field means in science.

It's comparable to me explaining a championship winning play in american football when you've never even seen a game before and I'm not allowed to explain the basic rules first.

Who is the target audience really? I have trouble understanding it, because I don't have the graduate mathematics to know the notations. All these shows that on youtube, news or Nova are interesting, but really, what are they trying to accomplish? I think it is only to gain public interest the best they can, considering the huge money investment in the LHC. The search for the Higgs boson (or lack of) is really only one step anyway as it doesn't get the full picture of explaining things.

 

[WaveHarmony]

The problem is compounded by the fact that I thought I understood the nature of mass as described by general relativity. I am happy with the explanation of the observed properties of mass in terms of spacetime curvature. The mass of the Earth curves spacetime so the moon responds to the spacetime curvature and follows its orbit. GR explains that any object with mass curves spacetime and the effect is cummulative. So electrons protons and neutrons curve spacetime. It seems to me that this explanation of the nature of mass is very clear and the only missing piece of the puzzle is 'how does an electron curve spacetime?' The Higgs field description doesn't seem to help with this aspect of the problem.

Can anyone explain to me in clear unambiguous terms how a Higgs field gives mass?
WaveHarmony

 

[Drakkith]

Who is the target audience really? I have trouble understanding it, because I don't have the graduate mathematics to know the notations. All these shows that on youtube, news or Nova are interesting, but really, what are they trying to accomplish? I think it is only to gain public interest the best they can, considering the huge money investment in the LHC. The search for the Higgs boson (or lack of) is really only one step anyway as it doesn't get the full picture of explaining things.

The shows have nothing to do with the LHC itself, it is purely entertainment for people who like science. Yes, entertainment. I read all kinds of stuff on science just because I enjoy it. The side benefit is that I also learn general knowledge.

The problem is compounded by the fact that I thought I understood the nature of mass as described by general relativity. I am happy with the explanation of the observed properties of mass in terms of spacetime curvature. The mass of the Earth curves spacetime so the moon responds to the spacetime curvature and follows its orbit. GR explains that any object with mass curves spacetime and the effect is cummulative. So electrons protons and neutrons curve spacetime. It seems to me that this explanation of the nature of mass is very clear and the only missing piece of the puzzle is 'how does an electron curve spacetime?' The Higgs field description doesn't seem to help with this aspect of the problem.

Can anyone explain to me in clear unambiguous terms how a Higgs field gives mass?
WaveHarmony

The higgs is a quantum theory, not a theory on gravitation. I believe you could say that the higgs explains inertial mass while relativity explains gravitational mass if you want to separate mass like that. But I'm really not sure.

 

[Mark M]

Can anyone explain to me in clear unambiguous terms how a Higgs field gives mass?
WaveHarmony

The Higgs has two responsibilities - to give mass to the force carriers of the weak force, and to give mass to the fermions. Let's start with the first.

The weak force is mediated by three massive particles, called the W+, W-, and Z bosons. One important aspect of the Standard Model is electroweak symmetry - at a sufficiently high temperature (at a time immediately after the big bang), the weak force becomes indiscernible from the electromagnetic force. Of course, this means that the W and Z bosons were massless. Breaking this symmetry is the job of the Higgs. Spin 1 particles like the W and Z bosons have at least two degrees of freedom. One way a massless particle could gain mass is by the absorption of a scalar (spin 0) particle as it's longitudinal mode (as it's second degree of freedom). A scalar particle that does this is called a Nambu-Goldstone boson. Originally, the Higgs had four degrees of freedom - H+, H-, H₀, and h. The thing about the first three is that they are equivalent to the longitudinal modes of W and Z bosons. So, they played the role of Goldstone bosons, and they were absorbed (or 'eaten' as it's often described) by the W and Z bosons, becoming their second degree of freedom, giving them mass.

This leaves us with one degree of freedom for the Higgs, h. This ends up being the scalar Higgs boson, the quantum of the Higgs field. Now, the Higgs field takes a constant value at every point in space - called the vacuum expectation value. Through Yukawa coupling, fermions interact with this vacuum expectation value (in terms if Feynman diagrams, you can think of a particle as interacting with the VEV at various vertices). By interacting with the VEV they attain mass, determined by the exact value of the VEV.

Note that, of course, this is a simplified explanation that leaves out more explicit details.

 

[AdrianTheRock]

The Higgs has two responsibilities - to give mass to the force carriers of the weak force, and to give mass to the fermions. Let's start with the first.

The weak force is mediated by three massive particles, called the W+, W-, and Z bosons. One important aspect of the Standard Model is electroweak symmetry - at a sufficiently high temperature (at a time immediately after the big bang), the weak force becomes indiscernible from the electromagnetic force...

That's not quite accurate, though, is it? One thing it seems to me about the term "unification" when used in the electroweak context is that it glosses over the fact that, prior to symmetry breaking, there are still two distinct forces: weak isospin (the Ws) and weak hypercharge (the B field), and these have different coupling constants. The theory describes how electromagnetism (the A field) and the Z then come about after symmetry breaking as orthogonal mixtures of W⁰ and B, with the Z also eating the H⁰.

Prior to symmetry breaking, there is no electromagnetic force as such. There are the W and B forces. The latter would behave just as electromagnetism does now, except it would be a bit stronger, but is separate.

 

[Mark M]

That's not quite accurate, though, is it? One thing it seems to me about the term "unification" when used in the electroweak context is that it glosses over the fact that, prior to symmetry breaking, there are still two distinct forces: weak isospin (the Ws) and weak hypercharge (the B field), and these have different coupling constants. The theory describes how electromagnetism (the A field) and the Z then come about after symmetry breaking as orthogonal mixtures of W⁰ and B, with the Z also eating the H⁰.

Prior to symmetry breaking, there is no electromagnetic force as such. There are the W and B forces. The latter would behave just as electromagnetism does now, except it would be a bit stronger, but is separate.

Yes, you're correct - that's why I posted that last sentence, that I omitted many technical details for clarity.

The Higgs mechanism breaks the electroweak symmetry $SU(2) X U(1)_{Y}$ to $U(1)_{em}$. The generator of $U(1)_{em}$, Q, is given by $$Q = \frac {Y} {2} + I_{3}$$ Where Y is the weak hypercharge, and I₃ is a component of the weak isospin. As you mention, this symmetry breaking mixes W₀ and B₀ to produce the photon and the Z, by $$\begin{pmatrix} \gamma \\ Z^{0} \end{pmatrix} = \begin{pmatrix} cos \theta_{w} & sin \theta_{w} \\ -sin \theta_{w} & cos \theta_{w} \end{pmatrix} \begin{pmatrix} B^{0} \\ W^{0} \end{pmatrix}$$ Thanks for pointing that out.

 

[WaveHarmony]

Thank you very much for your explanation. I can't form a clear picture of the meaning of the descriptions but this is my lack of understanding of the fundamental concepts of the standard model. The big disappointment for me is that the concept of mass which is so nearly fully explained by General Relativity is treated in a completely different way in particle physics with no apparent link between the concepts involved.

Does anyone else feel that physics is in need of a conceptual revitalisation to provide a single unified picture of everything?

WaveHarmony

 

[Dickfore]

How is mass fully explained in General Relativity?

 

[WaveHarmony]

We experience mass in our everyday lives and in experiments in two forms: gravitational mass and inertial mass. General relativity explains that a mass distribution has the effect of curving spacetime. GR also indicates that the effect of mass in curving spacetime is cummulative so that the greater the mass the greater the spacetime curvature. Mass also responds to spacetime curvature resulting in objects with mass seeking to move closer together. This so called gravitational force is really due to the objects seeking a lower energy. (Actually all so called fundamental forces can be treated as a search for a lower energy state).

Einstein also showed that there is an equivalence between an object in a curved spacetime environment (so called gravitational field) and an object under uniform acceleration indicating an equivalence between inertial and gravitational mass. So my claim is that GR fully explains the property we observe as mass with the one missing point that GR does not explain how mass curves spacetime. We can assume that the way mass curves spacetime is consistent so that electrons neutrons and protons which have mass do indeed curve spacetime in a similar way. So if we could explain how the electron curves spacetime then we would have a full explanation of the property mass.

WaveHarmony

 

[Drakkith]

Waveharmony, I could be wrong, but I don't believe the higgs is in any way related to general relativity. It is fully a quantum theory and has nothing to do with gravitation. General relativity explains that stress-energy curves spacetime, and since mass has energy it will do so as well.

 

[Dickfore]

We experience mass in our everyday lives and in experiments in two forms: gravitational mass and inertial mass. General relativity explains that a mass distribution has the effect of curving spacetime. GR also indicates that the effect of mass in curving spacetime is cummulative so that the greater the mass the greater the spacetime curvature. Mass also responds to spacetime curvature resulting in objects with mass seeking to move closer together. This so called gravitational force is really due to the objects seeking a lower energy. (Actually all so called fundamental forces can be treated as a search for a lower energy state).

Einstein also showed that there is an equivalence between an object in a curved spacetime environment (so called gravitational field) and an object under uniform acceleration indicating an equivalence between inertial and gravitational mass. So my claim is that GR fully explains the property we observe as mass with the one missing point that GR does not explain how mass curves spacetime. We can assume that the way mass curves spacetime is consistent so that electrons neutrons and protons which have mass do indeed curve spacetime in a similar way. So if we could explain how the electron curves spacetime then we would have a full explanation of the property mass.

WaveHarmony

So, how does GR explain the fact that the mass of the electron is 511 keV/c²?

 

[Mark M]

WaveHarmony - general relativity has nothing to do with the Higgs mechanism. The Higgs mechanism explains why particles have mass. General relativity explains why (macroscopic) massive objects gravitate.

 

[Naty1]

Wave:

So my claim is that GR fully explains the property we observe as mass with the one missing point that GR does not explain how mass curves spacetime.

that's an objective, for sure, but hasn't been achieved yet. The Higgs fields, so many of them I can't keep track, attempt to provide a mechanism for mass...But like many other components of the standard model, these Higgs fields are manual insertions individually tailored with the specific properties needed to provide different particles with the observed mass. A nice interim step, but hardly a comphrehensive theory.

I happen to be reading right now Alan Guth's 'The Inflationary Universe' and he discusses a few Higgs fields in Chapter 10/11. As an example, three Higgs fields are used to describe [construct] magnetic monopoles. So Guth talks about how he tried to avoid the magnetic monopole problem in a theory of inflation, that is, the fact that there could be many, but we observe none. How do we avoid them?

He realized if he could delay a phase transition in inflationary expansion#, horizons would increase in size and magnetic monopoles would disappear...be smeared out of existence, hence his reliance on a Higgs field with a false [temporary] vacuum...the old 'Mexican hat' energy density profile.

Sidney Coleman's 1977 paper THE FATE OF THE FALSE VACUUM describes "The process by which the Higgs fields of the false vacuum can tunnel thorugh the energy barrier..and Coleman's work was a big help to Guth.

Voila: when you know the physical characteristics required, you can invent mathematics to produce them and glue them into whatever model you'd like. It's not like all this stuff is available via first principles. How could Higgs fields, if they exist at all[+], not be related to gravity when both a related to mass...but that link apparently remains a mystery as already noted in a prior post.

# Guth points out what he thought he 'discovered' about inflation turned out to be in a 1925 Lemaitre paper from MIT that he knew nothing about...the de Sitter solution to Einstein's field equations...but apparently Guth coined the term INFLATION as part of his research.

+ I am referring to the existence of multiple Higgs fields not whatever might have be identifiey at CERN...

 

[WaveHarmony]

I agree that General Relativity doesn't predict the mass of the electron but it is the nature of the property mass that I am trying to focus on. If we perform a measurement of mass by experiment we are measuring the inertial or gravitational mass and the underlying theory that applies to these measurements is general relativity. So what we experience as mass is described by GR.

From a GR perspective when asked how does an electron curve spacetime we would naturally look to the structure of the electron for an explanation rather than an external agency such as a Higgs field that gives it mass.

The fundamental theories of physics seem to operate in their own separate compartments. General Relativity, the standard model, quantum theory, string theory all seem to have a different underlying world view. For the standard model, the elecron is an elementary particle so we don't ask about its structure. In quantum theory (copenhagen interpretation) the electron doesn't exist between emission and observation. String theory would describe the electron as a string but without any explanation of what a string is made of.

Each theory has grown up from mathematical models which correlate with observation and experiment but there does seem to be a need for fundamental examination of basic physics to develop a coherent physical world view in a top down way rather than starting from the maths. The theories are clearly correct in their own sphere of applicability but there is a need for unification.
WaveHarmony

 

[daumphys]

Higgs field can explain time dilation near light speed C?
It is Relativity theory area?

 

[Mark M]

Higgs field can explain time dilation near light speed C?
It is Relativity theory area?

No, it has no relevance to special relativity. Lorentz transformations occur to preserve a constant speed of light in all inertial frames of reference.

 

[WaveHarmony]

In trying to understand the nature of mass and starting from the question 'How does an electron curve spacetime?' there is another area of physical theory which seems relevant. The relationship between the energy and frequency E=hf where E is the energy equivalent of the mass and h is planks constant. This frequency relates to the wave character of the electron as evidenced by interference experiments. This emphasises the wave character of the electron as opposed to the particle character emphasised in the standard model.

If the electron is considered as a wavelike object in spacetime this would seem to fit better with the GR viewpoint than the Higgs field hypothesis.

WaveHarmony

 

[WaveHarmony]

We have seen how mass is handled differently by General Relativity as compared with the standard model of particle physics. I wanted to look at other physical attributes that are treated differently such as force. In the standard model the nuclear forces are explained by particle exchange. In general relativity the gravitational force arises as a result of spacetime curvature but we can also consider in GR that forces arise due to comparitive differences in energy. The apple falls to the ground to achieve a lower energy state. This approach borrowed from GR of considering forces as arising from differences in energy could well be applied to nuclear forces. In this case the mass deficit in the nucleus can also be seen as an energy deficit thus explaining the strong nuclear force without the need for particle exchanges.

WaveHarmony

 

[Drakkith]

In general relativity the gravitational force arises as a result of spacetime curvature but we can also consider in GR that forces arise due to comparitive differences in energy.

I don't believe energy is well defined in GR, so I don't think you could do such a thing.

 

[WaveHarmony]

I took a look at the wikipedia entry for General Relativity and under the section titled Einsteins equations, it talks about the energy-momentum tensor and so energy seems to be a fundamental part of GR theory.

I think it is also useful to consider the concept of irreducible physical properties. The idea is to find a set of physical properties which is the minimum needed to describe all of physics. So for example we can say in GR that mass is not irreducible because it can be reduced to energy. We can also say that a field can be considered as a three dimensional map of directional forces. So for example an electrostatic field is a map of electrostatic forces. Now if force can be show to depend on differences in energy, we have reduced the set of all physical properties to energy, momentum and spacetime coordinates. This approach suggests that we need to consider the electrostatic force as a difference in energy which applies for example when two electrons are in proximity. If the electrons move apart the energy is lowered. Also we need to consider electromagnetic waves (e.g. light) as an electromagnetic field with an underlying cause since we are considering field to be reducible.

Looking at the same issue from a standard model perspective, we can again say that mass is a reducible property because it depends on the Higgs field. Should we consider the Higgs field irreducible or does it have an underlying cause? As I understand it the Higgs field is caused by the Higgs boson. Also the concept of a force in the standard model is based on particle exchange. Particles themselves can be considered as irreducible in the standard model? Perhaps someone could help me apply the concept of irreducible physical properties to the standard model.

WaveHarmony

 

[Naty1]

I think it is also useful to consider the concept of irreducible physical properties. The idea is to find a set of physical properties which is the minimum needed to describe all of physics.

It's called THE THEORY OF EVERYTHING which would unite gravity with a GUT theory of particle physics:

http://en.wikipedia.org/wiki/Theory_of_everything

 

[WaveHarmony]

I looked at the Theory of Everything entry in Wikipedia and in the section Modern physics it states that 'A Theory of Everthing would unite all the fundamental interactions of nature: gravitation, strong interaction, weak interaction and electromagnetism.'

In my previous post I suggested that all of these interactions can be considered as due to energy differences if we adopt the GR viewpoint. The standard model approach would be to attempt to extend the standard model to include some kind of gravitational particle (graviton). My point is that before any theory of everything is constructed we have to construct a descriptive narrative or physical world view to set any mathematical analysis in context.

When we did physics and maths at school any problem to be solved had a clear descriptive context within which the mathematical analysis would be completed. We have lost this clarity in modern physics by having so many different competing world views.

WaveHarmony

 

[WaveHarmony]

There is a significant difference between your school problems and physics though. In your school problems, you know, or can define, the problem ahead of time. Physicists have to collect evidence of diverse types of phenomena across different time, distance, and energy scales before problems can even be defined. That turns out to be spectacularly hard.

Additionally the competing worldviews (I assume GR and the Standard Model) you write about are incompatible, but they are useful and accurate enough for almost all purposes.

You may find http://en.wikipedia.org/wiki/Renormalization and http://en.wikipedia.org/wiki/Renormalization#Renormalizability to be interesting introductory articles.

The above quote was received by email but doesn't seem to be in the thread.

What I feel is that we have to find a solution and not just accept that the competing worldviews are incompatible. Physics takes place in spacetime and it doesn't make sense that there should be several different and incompatible physical worldviews. The unification of physics is a very worthwhile goal and my point is that the starting point should be at the descriptive level.

I am convinced that if we could get clarity and consistency at the descriptive level then the unification of the laws of physics will not be difficult. As a starting point it is questions such as the nature of mass and the choice of fundamental physical properties (momentum, energy, spacetime) which need to be clarified and agreed.

WaveHarmony

 

[haael]

Despite I believe that GR is the proper way to unify physics, we can not stick to the particular mathematical formulation GR was written in. The unified theory may need some different mathematical objects.

The most general framework that we write our physical theories with is in fact Lagrange/Hamilton formalism.

 

[WaveHarmony]

Hello Haeel,

This is an important point of agreement, that the GR world view is the best starting point for the unification of physics. As I understand it the Lagrange/Hamiltonian formalism does deal with Energy/Momentum in spacetime so this would seem like a good approach.

What I wanted to discuss first was at the descriptive level. For example, to go back and look at the debates over the last 100 years concerning the interpretation of quantum theory and see if we can come up with an interpretation based on real physical waves in spacetime. This would be consistent with the GR view of the world in which spacetime has curvature and the potential to support wave trransmission of energy.

WaveHarmony

 

[haael]

But we can't say at this moment that the Universe looks like waves propagating over spacetime. This has yet to be proven. Our mathematical framework must allow both expressing that the world indeed does satisfy GR view, and that it does not.

There is no common picture of the world, since nothing is actually proven. If we confine ourselves to speak only in GR terms, we risk missing the possibility that the world is not like that.

 

[Drakkith]

WaveHarmony, I don't feel that anything you've said makes any sense. As in you've typed a lot out, but haven't really said anything. All I see is someone who is unhappy that QM and GR aren't compatible and wants to use GR as the basis for the next theory. Just saying that you think we should go back and try to agree on properties and fundamentals without giving a good explanation of how that could help and why it would even be possible in the first place doesn't give your opinion any credulity.