The Higgs Boson and General Relativity

[arupel]

"The presence of this field, now believed to be confirmed, explains why some fundamental particles have mass when based on the symmetries controlling their interactions they should be massless." (wiki)

It would seem, to myself, a novice, that the Higgs field and its corresponding particle, if they did not exist, there would not be mass.

In General Relativity, mass/energy deforms the geometry of the spacetime continuum.

It would seem that both QFT and GR have something in common: mass.

Is there any thinking of trying to reconcile the two because of this commonality?

 

[jedishrfu]

This is the central problem in physics today that is being addressed by String Theory and Loop Quantum Gravity as well as other proposed theories.

 

[vanhees71]

Well, most of the mass of the everyday-matter surrounding is is not due to the Higgs mechanism but dynamically generated by the strong interaction. This mechanism is a non-perturbative feature of QCD and thus not completely understood today. We are nevertheless pretty sure that this picture is correct, because lattice calculations of QCD can reproduce the hadron mass spectrum pretty well.

 

[Feeble Wonk]

I'm confused here. Is this just because the strong interaction localizes the more massive quark particles? My previous understanding was that the Higgs field was still needed to generate the mass.

 

[vanhees71]

The Higgs field generates the masses of the leptons and the W and Z bosons as well as the socalled current-quark masses. E.g., the current quark masses of the up and down quarks are a few MeV, but the proton, e.g., has a mass of about 938 MeV. Thus most of the mass is not due to the current-quark masses but dynamically generated by the strong interaction binding quarks and gluons together into hadrons.

 

[nikkkom]

"The presence of this field, now believed to be confirmed, explains why some fundamental particles have mass when based on the symmetries controlling their interactions they should be massless." (wiki)

It would seem, to myself, a novice, that the Higgs field and its corresponding particle, if they did not exist, there would not be mass.

There would not be *rest* mass.

If you remove Higgs field from Standard Model, all particles become massless: they move with the speed of light. But they still would have energy, and their bound systems (assuming such systems are possible in this model, of which I'm not sure) would have mass.

 

[vanhees71]

First of all if you say mass in the 21st century you always refer to the rest mass (I prefer to call it invariant mass). Second, even if there was no Higgs boson, we'd pretty see the same mass of the usual matter surrounding us in everyday life, because almost 99% of it is created dynamically via the strong interaction and not the Higgs mechanism. The latter is only responsible for the current-quark masses but not for the constituent-quark masses relevant for hadron phenomenology.

 

[nikkkom]

First of all if you say mass in the 21st century you always refer to the rest mass (I prefer to call it invariant mass). Second, even if there was no Higgs boson, we'd pretty see the same mass of the usual matter surrounding us in everyday life

Will we really see "usual matter" as such?
I'm not sure massless electrons will form atoms with hadrons.
Massless quarks would make hadrons very different from ones we see today (for one, would strange/charmed/b/t hadrons decay to protons/neutrons?)

 

[vanhees71]

Well, it's not clear to me what really would happen if there was no Higgs boson (or even no weak interactions), but a good effective description of hadrons is (unitarized) chiral perturbation theory, i.e., you treat the small quark masses as perturbations. The chiral limit is not too far from the real world from this point of view!

 

[mfb]

That would work nicely in a world with just three quarks, but with six massless quarks I would be surprised to see the same results as with three.
And, of course, electrons would not have their orbits because their binding energy is proportional to their mass.

 

[ChrisVer]

It would seem, to myself, a novice, that the Higgs field and its corresponding particle, if they did not exist, there would not be mass.

I'm reading that a lot from people. but I don't like this way of talking for the Higgs field...
To make it clear: if the Higgs field happened not to exist we would have to find an alternative way to give the particles their masses which we know they have... the way you put it seems like the Higgs was introduced and suddenly gave us "masses"... but the thing is that we introduced the higgs field+ the Spontaneous Symmetry Breaking to get those masses which we knew they were there [but the symmetries didn't allow them].
The mass was there; we would need to find ways to bring it in [in the worst case scenario you'd impose the masses by explicitly breaking the symmetry ; waiting on the theorists' attack for this point of mine especially I think for the fermions]... it happened to enter through the Higgs Mechanism and all those beautiful [or ugly] stuff that happened so far...
I am not sure but I think speaking of "massless" quarks or leptons or even W/Z bosons is not the right way to approach it...

 

[mfb]

Well, you can ask "how would the world look like with the Standard Model but without Higgs mechanism". Differently, obviously, but how?

 

[vanhees71]

That would work nicely in a world with just three quarks, but with six massless quarks I would be surprised to see the same results as with three.
And, of course, electrons would not have their orbits because their binding energy is proportional to their mass.

Sure, the heavy quarks (c, b, t) get most of their mass via the Yukawa couplings to the Higgs.