Well-motivated theories with nonzero PPN ζ?

[bcrowell]

Does anyone know of any well-motivated theories of gravity -- preferably viable ones -- that have nonzero values of the PPN ζ parameters, which describe momentum nonconservation?

In http://relativity.livingreviews.org/Articles/lrr-2006-3/articlesu6.html#x12-200003.3 , table 3 shows some theories that are probably well motivated, but none of them have any of the ζ_i nonzero.

Presumably any such theory would be strongly constrained by lunar laser ranging.

 

[Old Smuggler]

Does anyone know of any well-motivated theories of gravity -- preferably viable ones -- that have nonzero values of the PPN ζ parameters, which describe momentum nonconservation?

In http://relativity.livingreviews.org/Articles/lrr-2006-3/articlesu6.html#x12-200003.3 , table 3 shows some theories that are probably well motivated, but none of them have any of the ζ_i nonzero.

Presumably any such theory would be strongly constrained by lunar laser ranging.

I don't know any offhand (maybe the Belinfante-Swihart theory (non-viable)), but perhaps you can find something
useful on this site

http://www.phy.olemiss.edu/~luca/

 

[bcrowell]

I don't know any offhand (maybe the Belinfante-Swihart theory (non-viable)), but perhaps you can find something
useful on this site

http://www.phy.olemiss.edu/~luca/

Thanks for the suggestions! Turns out the Belinfante-Swihart actually has all the ζ parameters equal to zero: http://authors.library.caltech.edu/9988/

 

[atyy]

http://arxiv.org/abs/gr-qc/0611006

 

[bcrowell]

http://arxiv.org/abs/gr-qc/0611006

Aha! Thanks!