Higgs Boson Discovered?!

[sol invictus]

That seems inconsistent: that some of the mass is caused by the Higgs field, while other forms of mass don't require any Higgs field.

There's nothing "inconsistent" about it.

Then your claim is different than the article I quoted:

"So light is definitely affected by gravity. Since light has energy, it is also a source of gravitational effects on other objects, although not a very strong one under ordinary circumstances." -- http://van.physics.illinois.edu/qa/listing.php?id=19800

The fact that light is a source of and is affected by gravity does not mean that light gravitationally attracts light under all conceivable circumstances.

 

[Farsight]

Not to mention it's speculations, boldly presented as fact, that "rest mass never applies to a system at complete rest, because such systems do not exist; there will always be internal dynamics" (implying that electrons somehow have stuff whizzing around inside them)

They aren't called spinors for nothing, and the electron magnetic dipole moment isn't magic. People tend to insist that no motion is involved in intrinsic spin, and say there's no classical equivalent. But they forget about tornados. A tornado has intrinsic spin. Without it, it isn't a tornado any more. They forget about moebius strips too.

...and the claim that elementary particles all have non-zero spin (implying that the Higgs observed by CERN cannot be spin-0 like the standard model Higgs).

They only observed decay products. Whatever decayed did so almost instantly. It doesn't last long enough to spin.

 

[ctamblyn]

Then your claim is different than the article I quoted:

"So light is definitely affected by gravity. Since light has energy, it is also a source of gravitational effects on other objects, although not a very strong one under ordinary circumstances." -- http://van.physics.illinois.edu/qa/listing.php?id=19800

I'm not sure whether you caught my link earlier:

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

Basically, and perhaps intuitively if you imagine graviton exchange as a model for gravity (just a thought, not a statement of fact), two photons both heading off in the +x-direction (say) will not interact gravitationally. On the other hand, if one photon is going in the +x direction while the other is going in the -x direction, then they will interact.

 

[edd]

They aren't called spinors for nothing, and the electron magnetic dipole moment isn't magic. People tend to insist that no motion is involved in intrinsic spin, and say there's no classical equivalent. But they forget about tornados. A tornado has intrinsic spin. Without it, it isn't a tornado any more. They forget about moebius strips too.

I'm pretty sure it hasn't escaped even your notice that tornados are not point-like particles.

 

[Anders Lindman]

No, it's just more detailed.

So the effect of gravity depends on the photon's relative velocity? I doubt that. The gravity is dependent on the photon's frequency, not its velocity. So two photons traveling side by side parallel to each other will attract each other gravitationally dependent on their energy, i.e. their frequency.

 

[Anders Lindman]

One photon has such a slight effect on another that we can never hope to measure it.

The effect of gravity is still there even if our current instruments are unable to measure it. Would you agree that two photons traveling side by side parallel to each other in vacuum will be pulled together by gravity?

 

[Anders Lindman]

I'm not sure whether you caught my link earlier:

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

Basically, and perhaps intuitively if you imagine graviton exchange as a model for gravity (just a thought, not a statement of fact), two photons both heading off in the +x-direction (say) will not interact gravitationally. On the other hand, if one photon is going in the +x direction while the other is going in the -x direction, then they will interact.

Are you claiming that the gravity for a photon is dependent on its relative velocity?

 

[ctamblyn]

They aren't called spinors for nothing, and the electron magnetic dipole moment isn't magic. People tend to insist that no motion is involved in intrinsic spin, and say there's no classical equivalent. But they forget about tornados. A tornado has intrinsic spin. Without it, it isn't a tornado any more. They forget about moebius strips too.

Electron "spin" is a different beast to the rotation of a tornado. There is no evidence that the electron is literally a rotating ball of charge, for example.

They only observed decay products. Whatever decayed did so almost instantly. It doesn't last long enough to spin.

That's not how it works. The spin of whatever decayed would leave its imprint on the distribution of decay products, regardless of how short-lived it was. It will be hard to detect, but not impossible.

ETA:

Someone correct me if I'm wrong, but I believe there are far shorter-lived particles than the Higgs which have been detected (e.g. the W and Z), and have had their non-zero spins determined. So short life does not force spinlessness.

 

[ctamblyn]

Are you claiming that the gravity for a photon is dependent on its relative velocity?

To be specific: I'm claiming that, according to an exact solution of GR's field equations, the gravitational interaction of two photons depends on their relative directions.

I linked to the Wikipedia article twice already, but here's Bonnor's original paper:

http://link.springer.com/content/pdf/10.1007/BF01645484

It deals with beams rather than individual particles, but the same result holds.

 

[Anders Lindman]

To be specific: I'm claiming that, according to an exact solution of GR's field equations, the gravitational interaction of two photons depends on their relative directions.

I linked to the Wikipedia article twice already, but here's Bonnor's original paper:

http://link.springer.com/content/pdf/10.1007/BF01645484

It deals with beams rather than individual particles, but the same result holds.

That's a bit over my head, lol, but it talks about gravity waves. If gravity is caused by gravitons (which I doubt, but for the sake of argument), then if the photons are traveling in OPPOSITE directions for example, then how will the gravitons be able catch up with the photons? Faster-than-light gravitons? LMAO.

 

[ctamblyn]

That's a bit over my head, lol, but it talks about gravity waves. If gravity is caused by gravitons (which I doubt, but for the sake of argument), then if the photons are traveling in OPPOSITE directions for example, then how will the gravitons be able catch up with the photons? Faster-than-light gravitons? LMAO.

The article talks about extended beams, like two infinite parallel rods if you like. In that case the interactions go as I described.

Similarly, if you start off with two point-like photons far apart which then approach each other, you will get an interaction.

In your scenario though, where I picture two individual point particles being emitted at distinct points and moving directly apart, each at the speed of light, they could not interact by any means, gravity or otherwise (excluding space being wrapped up like a cylinder, wormholes etc.). So, that's an interesting exception to what I stated earlier. For some reason I didn't think of that.

Now, In case I got that wrong, perhaps one of the resident physics-gods could chime in.

 

[mijopaalmc]

I'm pretty sure it hasn't escaped even your notice that tornados are not point-like particles.

lol wut? srsly? no wai!

 

[Reality Check]

They aren't called spinors for nothing,...

What are "they"? The context seems to be electrons but they are never called spinors.

Spinors are mathematical objects that are used to describe quantum spin which has nothing to do with classical spin, e.g. electrons do not actually spin around an axis like your silly example of a tornado.

In mathematics and physics, in particular in the theory of the orthogonal groups (such as the rotation or the Lorentz groups), spinors are elements of a complex vector space introduced to expand the notion of spatial vector. Unlike tensors, the space of spinors cannot be built up in a unique and natural way from spatial vectors. However, spinors transform well under the infinitesimal orthogonal transformations (like infinitesimal rotations or infinitesimal Lorentz transformations).

 

[Anders Lindman]

The article talks about extended beams, like two infinite parallel rods if you like. In that case the interactions go as I described.

Similarly, if you start off with two point-like photons far apart which then approach each other, you will get an interaction.

In your scenario though, where I picture two individual point particles being emitted at distinct points and moving directly apart, each at the speed of light, they could not interact by any means, gravity or otherwise (excluding space being wrapped up like a cylinder, wormholes etc.). So, that's an interesting exception to what I stated earlier. For some reason I didn't think of that.

Now, In case I got that wrong, perhaps one of the resident physics-gods could chime in.

So, the Higgs field is Lorenz invariant, while gravity is not? As for the special case, how can black holes hold the photons back via gravitons unless they travel faster than the speed of light, which would violate Einstein's relativity?

 

[Anders Lindman]

Ok, if the Higgs field is Lorenz invariant, then it can ONLY give rest mass to particles. Otherwise the mass would be dependent on the particles' velocity relative to the Higgs field as an absolute frame of reference.

 

[Tubbythin]

They aren't called spinors for nothing, and the electron magnetic dipole moment isn't magic. People tend to insist that no motion is involved in intrinsic spin, and say there's no classical equivalent. But they forget about tornados. A tornado has intrinsic spin. Without it, it isn't a tornado any more. They forget about moebius strips too.

A tornado has a diameter of several metres. An electron does not.

They only observed decay products. Whatever decayed did so almost instantly. It doesn't last long enough to spin.

How long do you think it takes a point particle to complete a single revolution?

 

[Perpetual Student]

How long do you think it takes a point particle to complete a single revolution?

ε2π seconds?

 

[Kwalish Kid]

How long do you think it takes a point particle to complete a single revolution?

"How long can you tread water?"

 

[sol invictus]

Are you claiming that the gravity for a photon is dependent on its relative velocity?

The gravitational attraction between any two objects or particles is dependent on their relative velocity - or more precisely, the dot-product of their 4-momenta. That's a Lorentz invariant quantity.

So, the Higgs field is Lorenz invariant, while gravity is not? As for the special case, how can black holes hold the photons back via gravitons unless they travel faster than the speed of light, which would violate Einstein's relativity?

Gravity is more than just Lorentz invariant. Lorentz invariance is the set of symmetries of flat spacetime. Gravity determines the spacetime, which (away from singularities) is locally flat... so gravity is locally Lorentz invariant, but globally can have other symmetries.

Ok, if the Higgs field is Lorenz invariant, then it can ONLY give rest mass to particles. Otherwise the mass would be dependent on the particles' velocity relative to the Higgs field as an absolute frame of reference.

That's correct.

 

[ctamblyn]

So, the Higgs field is Lorenz invariant, while gravity is not? As for the special case, how can black holes hold the photons back via gravitons unless they travel faster than the speed of light, which would violate Einstein's relativity?

Sol already answered, so I'll just add that I came across this page on John Baez's site that you might find interesting (I think it answers your question, in a roundabout way):

http://math.ucr.edu/home/baez/physics/Relativity/BlackHoles/black_gravity.html

(It's worth remembering, though, that no-one has observed a graviton; they are hypothetical particles, for the time being at least. GR itself already describes in classical terms how light is affected by gravity and why it can't escape from inside the event horizon of a black hole.)