- #1

Peter Morgan

Gold Member

- 246

- 44

@vanhees71 reminds us that

[I'd be pleased to know of a clear, more recent reference.]

The really pertinent phrase is "If the Källén-Lehmann weight function is continuous, there are no particles

associated with the corresponding generalized free field". Such a free field clearly exhibits different translation/mass properties than a free field that has a singular mass distribution, and yet as far as local properties of such a generalized free field are concerned, we can introduce a mass distribution that is as close to singular as we like, so that the local behavior, out to many light years, say, would be identical. Of course although we only compute the S-matrix between states at asymptotic separation, we in fact only measure the distribution of events in detectors in high energy experiments at separations up to a few meters (up to hundreds of kilometers for the outliers, neutrinos).

What studies are there of such a suggestion in the dark matter literature?

Is my understanding that unparticles have been suggested (but not successfully) as a model for dark energy correct?

which suggests something I've wondered about for a while, whether dark matter might be adequately modeled by generalized free fields, which do not have asymptotic free states. Ray Streater, in Rep. Prog. Phys. 1975The only interpretation of particles is in terms of asymptotic free states, and the observable predictions are in S-matrix elements.

**38**771-846, "Outline of axiomatic relativistic quantum field theory" has this account:[I'd be pleased to know of a clear, more recent reference.]

The really pertinent phrase is "If the Källén-Lehmann weight function is continuous, there are no particles

associated with the corresponding generalized free field". Such a free field clearly exhibits different translation/mass properties than a free field that has a singular mass distribution, and yet as far as local properties of such a generalized free field are concerned, we can introduce a mass distribution that is as close to singular as we like, so that the local behavior, out to many light years, say, would be identical. Of course although we only compute the S-matrix between states at asymptotic separation, we in fact only measure the distribution of events in detectors in high energy experiments at separations up to a few meters (up to hundreds of kilometers for the outliers, neutrinos).

What studies are there of such a suggestion in the dark matter literature?

Is my understanding that unparticles have been suggested (but not successfully) as a model for dark energy correct?

#### Attachments

Last edited by a moderator: