Did you not argue in your paper that the DM candidate could be a WIMP (which is a linear combination of super partners)? Furthermore, it is stated in your paper that the particles have a dark U(1) charge (but there is overall charge neutrality). Puzzled…

By the way the link to Jay Alfred’s article should be:

http://ezinearticles.com/?Dark-Matter—Plasma-of-Super-Particles&id=1240357

(without the full-stop at the end … hope it works this time)

Interesting. Guess that shows that I haven’t been following axions very closely.

Robert Bast,

Anti-light is a really bad name. It can only cause confusion as it evokes anti-matter, which is a completely different phenomenon. In fact, there is an anti-particle to the photon: it’s called the photon (so yes, this means that just as an electron and a positron can annihilate with one another to produce all sorts of things, a photon can annihilate with another photon, if the pair have enough energy between them to produce anything).

I honestly don’t see how the speed of dark photons could be any different from normal photons unless they have some mass, which would cause the force to be short range, which would be something other than what Sean is proposing.

L. C.

Also, “dark photons” as imagined by Sean and others are not like negative energy that can cancel out ordinary light or energy, they are “dark” because we can’t see them (i.e., they don’t interact with ordinary matter-energy enough.)

Something you may want to consider is how fast a dark photon travels….

Sean on Nov 10th, 2008 at 12:32 pm

Actually, axions are (usually) very much cold dark matter, not warm. It’s true that their masses are small — small enough to make them hot dark matter, if they were produced in thermal equilibrium. But they’re not; they come into existence at zero momentum as part of a Bose condensate. The energy per axion is enormously smaller than the energy per CMB photon.

Well, structure formation arguments basically rule out MACHO’s, as we see the evidence of dark matter even within the CMB, which was long before any compact objects had a chance to form. The Bullet Cluster does not, because MACHO’s are just as non-interacting as the stars and galaxies: they’re few and far between, so they mostly just miss one another in a collision like that.

The difficulty with axions is that they have very low mass, which makes them a candidate for “warm” dark matter, which seems to not fit well with our current observations of structure formation. But, more observations are necessary to really say this with confidence, and perhaps the 21cm and cosmic shear observations will weigh in here to say something definitive.

http://www1.jlab.org/ul/calendar/calendar_date.cfm?date=7&month=11&year=2008

“Search for Dark-Matter Particles in Photon-Photon Interaction at Optical Frequencies”

He went over the basics of DM, including evidence from the Bullet Cluster (since approaching clumps of DM blew past each other and their formerly associated clumps of matter, I guess that close to rules out regular matter (RM) bases of DM such as MACHOs?) Andrei considers axions (of some sort) to be a good choice of what DM consists of, curiously not mentioned here. He discussed the LIPSS experiment, interesting to me as offbeat physics but also since I know and got to brainstorm with one of the main experimenters (K Beard.) I had already heard how hard it was to do right. Briefly: Take advantage of photon-photon coupling to produce some axions A or other DM particle by shining powerful laser through magnetic field. Stop conventional photons with a wall, and convert A back into photons with magnetic field on other side. It would be a tiny effect, much noise from cosmic rays, and the experiment turned out negative. That doesn’t mean “no DM can be produced from photon-photon reactions” but the mass must be even less (“milli-eV”)

Another idea was directly relevant to “dark photons”, and that was the creation through the same means of what Andrei and some others call “paraphotons” which is presumably the same sort of idea. I told Andrei that should mean an equivalent para-charge analogy for the DM particles, which seemed odd to me and would maybe have prevented DM in the Bullet collision from cross-passing like that – he said, it weakly couples even to itself. He appreciates that we wouldn’t just have “four forces” in the universe any more.

I forgot to bring up, that paracharged particles seem to imply an analogous “anti-dark matter” regime, and then the same question as for RM of why it didn’t all mutually disintegrate etc. (Also, they would be stable, not with 10^10 s half-life decay even into paraphotons, since paracharge presumably is conserved. BTW axions are thought to decay into ordinary photons.) There are other odd issues, like what role to virtual paraphotons play in the scheme of things? Maybe if virtual photons give the wrong vacuum energy level for DE, then VPPs do it right?

Why is this not true of gravity?

From what I understand, Matti Pitkanen’s work also directly discusses the possibilities of dark photons, dark chemistry, and dark biology.

A brief Letter to the Editor, Foundations of Physics is at: http://cavekitty.ca/db_origin.pdf

I’m hoping that they’ll publish it, since these are all very good ideas. I’d just hate to see Pitkanen’s hard work go unnoticed, etc, etc, etc.

Lawrence B. Crowell

Lawrence B. Crowell

Marshall: I agree that the gravitational effect of DM might be detectable in the solar system, even though it would be small. It is not clear to me that the Pioneer craft reflect this physics. That this anomaly is absent from the Voyager craft makes me suspect this is due to a leak or some differential cold gas to solid deposition or sublimation of atoms on the surfaces of the craft.

Lawrence B. Crowell