# Quantum Gravitons

1. Feb 10, 2004

### Orion1

Given that the Standard Model states that only three families exist, and given that gravitons can exist with mass, why could it not be implied that there are also three graviton types?:

$$g^0_e$$ - electro-graviton
$$g^0_\mu$$ - mu-graviton
$$g^0_\tau$$ - tau-graviton

Given that no primordial graviton Cosmic Background Radiation exists, can it also be implied that all 'implied gravitons' must have a short 'lifetime'?

Given that gravitons have a short 'lifetime', what could have been their most probable decay products?

Last edited: Feb 10, 2004
2. Feb 10, 2004

### suyver

The standard model doesn't state that only three families exist. It just seems so from the experimental data so far. (See here for a fit of the data to the standard model calculations)

The fact that there are (probably) 3 families has to do with the weak force. Why should this influence the gravitational force as well? After all, there is also only one type of photon.

Why is it 'given that no primordial graviton Cosmic Background Radiation exists'? Experiments are still running (it's just hard to measure gravitons: their interaction is quite weak to say the least)...

Why is it 'given that a graviton has a short lifetime'?

3. Feb 10, 2004

### GRQC

The Standard Model calls for three families of fermions. The fundamental forces are mediated by gauge bosons, of which the graviton is a "member" (spin-2). The number of bosons which correspond to a particular force is determined in part by the number of generators of the symmetry group, hence why there is 1 photon, 3 weak vector bosons, and 8 gluons.

4. Feb 10, 2004

### suyver

Re: Re: Quantum Gravitons...

Are you sure? I always thought that the number of families is not dictated by the standard model. See also this thread.

5. Feb 10, 2004

### GRQC

Re: Re: Re: Quantum Gravitons...

The Standard Model has three generations of fermions. If there are shown to be more than three, then the Standard Model is incorrect and needs to be adjusted. Calling for a fourth sterile neutrino, for example, constitutes an extension of the current Standard Model.

I suppose it's largely an issue of semantics.

6. Feb 10, 2004

### GRQC

If gravitons have a short lifetime, then how can gravitation be a long-range force?

7. Feb 10, 2004

### Haelfix

We don't know the amplitude of a graviton. What we do know, is that to first order, it pops out something very close to general relativity

However, it is the case that they may exist graviton partners in some symmetry group. For instance, SUGRA outputs a supersymmetric partner, called the gravitino.

As far as the 3 families in the SDM, it is not known why they are there, you have to go to theories beyond the SDM to get that.

8. Feb 10, 2004

### GRQC

Only if you believe SUSY. But hey, it's 50% verified at this point, right?

9. Feb 10, 2004

### Orion1

Given that a graviton is a spin-2 gauge boson and there are 3 vector bosons, could it be implied that there are also 3 vector gravitons with 3 gravitinos?

Symmetry Generator# = Fermion Family#

3 vector gravitons: (mass symmetry)
$$g^0_e$$ - electro-graviton
$$g^0_\mu$$ - mu-graviton
$$g^0_\tau$$ - tau-graviton

3 vector gravitinos: (supersymmetry)
$$gv^0_e$$ - electro-gravitino
$$gv^0_\mu$$ - mu-gravitino
$$gv^0_\tau$$ - tau-gravitino

I suppose such a system may be trans-Standard Model, I am only implying that 'leptonic-like' gauge vector gravitons with supersymmetry may exist with mass gauged bosonic gravitons.

According to my understanding, there are several types and classes of graviton theories, including a String Theory model, which are primarily based upon five theories:

1. Newton's Theorem (Gravitation) (relative spin)
2. Curved-Space-Time (general relativity) (spin 2 ???)
3. Graviton Waves (inverted Space-Time Waves), (supernovae produced) (spin 2 ???)
4. Graviton Gauge Bosons (mass, field exchange particles) (spin 2)
5. String Theory (vibrating strings) (spin 2)

If gravitation is really a product of the field exchange of Graviton Gauge Bosons, they why would it be necessary to curve space-time for this effect?

If gravitation is really a product of Graviton Waves (inverted Space-Time Waves), supernovae should produce enormous inverted amplitudes, which should have been optically detectable via the lensing effect.

If gravitation is really a product of first order Graviton Gauge Bosons, it is reasonable to imply that Graviton Gauge Bosons with, or without mass or charge must exist at higher orders to complete Gauge Theory or GUT, or TOE.

Last edited: Feb 11, 2004
10. Feb 11, 2004

### GRQC

There are 3 bosons for weak interactions, because that is the associated group structure. The three weak bosons (Z, W+, W-) have nothing to do with the three families of leptons, short of being responsible for flavor-changing interactions.

There is 1 photon and 8 gluons -- which has even less of a correlation.