Jefferson Accelerator To Search For 'Dark Photons'

[Tsyal Maktoyu]

http://www.popsci.com/science/article/2012-04/while-lhc-hunts-higgs-jefferson-accelerator-looks-illuminate-dark-photons

Fascinating. From the sounds of it, what they are looking for appears to be dark matter according to the theory of supersymmetry. Best of luck to them. Though it seems like a different theory of supersymmetry than I've heard before. From what I've read it would mean the dark photon would technically be a fermion, but according to this particular theory it would retain it's bosonic properties (at the same time, I couldn't help but think "neutrino" while reading their theory), and not only that, but it would be a boson for all our forces plus another (the "photino" force, a supersymmetric force regarding the interactions of photons. Each supersymmetric particle that is a fermion in our world would be a boson for a unique force to it's partner).

[Seze Mune]

Dark matter supposedly makes up 85% of the universe and yet we've yet to find any actual dark matter.  I don't know how they figured that out and what the implications are, and what is the difference between dark matter and dark energy anyway?   Anyone want to try explaining to a six-year-old what makes this any different from believing in elves?

Because maybe dark matter is just an artifact of the tools we're using to probe the universe.

[Tsyal Maktoyu]

Simply put, dark matter and energy are umbrella terms for yet undiscovered types of matter that do not interact electromagnetically, and are thus "dark" to us. Imagine our matter and energy, just not interacting with the electromagnetic force, and you begin to get a basic idea of what dark material is in basic terms. There's many theories out there trying to describe it, super symmetry is one. Mirror matter is another, which involves mirroring how isospin works within singlets and doublets of the two fermion families (in short: how upper level quarks and lower level quarks change places, or how electrons/muons/taus become neutrinos).

Also, some theorized forms of dark matter and energy aren't that exotic. Remember, dark matter only means matter and energy we have yet to map directly, but we know exists indirectly, through the motion of heavenly bodies that wouldn't be possible with those bodies alone. For example, neutrinos are an example of "hot" dark matter, because they only interact with gravity and mass, and not electromagnetism (how we make our measurements). Another possibility for dark matter is orphaned planets made of normal matter. We can't detect them directly as they are not paired with a star. The gravitational effects of these stray planets can have an effect similar to dark matter.

Personally, I feel virtual particles might be a form of dark energy. What we see might just be an interstellar example of the Cassimir Effect. Plus micro black holes might play a role, as well.

[Lance R. Casey]

Dark matter supposedly makes up 85% of the universe and yet we've yet to find any actual dark matter.  I don't know how they figured that out and what the implications are, and what is the difference between dark matter and dark energy anyway?   Anyone want to try explaining to a six-year-old what makes this any different from believing in elves?

Dark matter is a proposed solution to the problem that the observed visible (i.e. not "dark") matter in galaxies cannot account for the observed gravity exerted by those same galaxies. In other words, there must be something else which has the same gravitational effects as ordinary matter, but does not emit or reflect EM radiation and is therefore not detectable by such means. This "something else" is called dark matter because of the latter property.

Dark energy, on the other hand, is the name given to the (unknown) cause of the observed effect that the universe is not only expanding, but it is doing so at an accelerated rate. For this to be possible there needs to be something which counteracts the effects of gravity, which would otherwise slow down the expansion. For lack of a better term, this "something" has been dubbed "dark energy", probably by analogy to "dark matter".

Neither "darkness" has been pinned down yet, but the effects have been. We have yet to see elven signs of comparable strength.

Because maybe dark matter is just an artifact of the tools we're using to probe the universe.

Quite possible, but this suggests otherwise.

[Seze Mune]

Tantalizing.

What are the chances that dark matter/energy is actually the matrix for visible matter/energy?  In other words, everything that exists physically including our bodies is made up mostly of dark matter/energy.  This dark energy/matter manifests most completely somewhere within the five to eleven dimensions posited by quantum theory.

When certain portions of this energy intersect with our three palpable dimensions we experience physicality and everything explicable by more classical physics, while the vast majority of our dark energy/matter matrix passing through our three dimensions leaves its signature only in the gravitational field.

Or am I way off track here?

[Tsyal Maktoyu]

It's a thought. That's why I personally think virtual particles might play a role. At our current energies, electromagnetism (and then, only partially, mostly with the emission of energy along the electromagnetic spectrum) is the only force we really experience as "real." The others are mitigated through virtual particles with near instantaneous lifespans. They too, cannot be directly observed, but we can see their effects. Starting to sound familiar? Not to mention how it would be a way to describe interstellar dark collisions: the occasional dark pair (I'll describe later) collides with a photon/neutrino/proton, imparting one or both with enough energy to become "real," and thus observable, along with any decay products afterwards.

Back to pairs, all virtual particles we normally encounter are matter/antimatter, where the only force inverted is electromagnetism. I theorize that there are dozens, if not hundreds of different exotic types of matters and inverse-matters, which interact with different forces, and have inverse interactions with one or more of those forces. Many of these might not interact electromagnetically, and might be stable (plus virtual forms), and could all be candidates for dark matter.

Sorry if that didn't make sense, I get a bit of a head rush when the topic comes up, all my thoughts come at once.

[`Eylan Ayfalulukanä]

It is interesting that we also have tons of evidence to support the existence of gravity waves, and we have yet to directly measure any. They are trying to detect gravity waves by using electromagnetic detectors to detect changes in the fabric of spacetime cause by variations in the strength of the gravitational field (Check out the LIGO experiment). We clearly observe that electromagnetic signals are affected by gravity, even though the force carrier for electromagnetism (the photon) is massless.  Could it be that the reason we are not having any luck measuring gravity waves have something to do with the fact that photons are being affected at the same time, perhaps in a manner that cancels out the detection of gravity waves?

Now, let's apply this idea to dark matter and energy. Perhaps these entities are not so unusual, just hard to measure, because they elicit an equal but opposite force on any electromegnetic energy that encounters it? We undoubtedly live in a sea of dark matter and energy, but there is no real correlation whatsoever by the type and amount of these entities that are near us. We just simply cannot measure it with this kind of tool. Just like gravity waves, we see lots of evidence to support the existence of dark matter/energy, but are not successful at measuring any effects from its existence.

Our observing of the Casimir effect (now, both statically and dynamically) strongly suggests that there is something other than nothing in the vast space between particles of baryonic matter. The Higgs field is likely another manifestation of this that needs a lot more investigation.

In any case, there seems to be a correlation between the presence of dark matter and baryonic matter. Where there seems to be a concentration of dark matter, there baryonic matter is also found. The opposite case does not appear to be true.

As Seze would say, both our senses and our instruments are not measuring everything....

[Tsyal Maktoyu]

For LIGO, I wonder if certain relativistic effects might be the cause for the lack of results. I think it can be described by length contraction, in which an object appears to shrink (as seen by an outside observer) at close to the speed of light, in the direction of travel. Why would take a while to explain, so I'll leave it at. Though as I've said, this is only relative to an outside observer, as the observer traveling at close to C would not experience the effect. With that said, I'm sure a similar length-distortion effect if space time changes are a result of gravity shifts rather than speed. Which would mean that if the entire system is effected by a wave at the same time (including detector), the effect would not be seen by the detector. One would need to change the location of the detector, but how, I'm not sure.

[`Eylan Ayfalulukanä]

For LIGO, I wonder if certain relativistic effects might be the cause for the lack of results. I think it can be described by length contraction, in which an object appears to shrink (as seen by an outside observer) at close to the speed of light, in the direction of travel. Why would take a while to explain, so I'll leave it at. Though as I've said, this is only relative to an outside observer, as the observer traveling at close to C would not experience the effect. With that said, I'm sure a similar length-distortion effect if space time changes are a result of gravity shifts rather than speed. Which would mean that if the entire system is effected by a wave at the same time (including detector), the effect would not be seen by the detector. One would need to change the location of the detector, but how, I'm not sure.

I think you and I are on the same page, if not the same paragraph.

This, I think, is why gravity wave detectors have two arms that are orthogonal to each other. Imagine a gravity wave propagating past a detector. The direction of travel of the wave will form an angle with one arm of the detector. It will form an angle +/- 90 degrees with the other leg. This should cause the effect of the gravity wave to be 'experienced' differently by each arm. While immeasurable in one arm alone, it is measureable as a differential between the two arms. In an ideal case, the gravity wave would strike one arm completely parallel to it, and the other leg perpendicular to it. The perpendicular arm would experience spacetime expansion and contraction on it's length, while the other arm would experience such effects only across its section. The former arm would not see any changes if refernced to itself. But if compared to the arm that was not experiencing much of the spacetime effects, you would see a difference in propagation velocities of the laser beams in the two arms.

Now, maybe there is something about gravity waves we don't understand, that would affect both arms in such a way that you would not be able to measure the effect with an electromagnetic method, such as laser propagation time. So although we can see other effects of gravity waves in the distant universe, we will never measure one with this kind of apparatus.

[Human No More]

That makes sense, but you'd need more than two to get a reading at the desired angle of incidence unless the range was relatively wide; if 45deg was a worst case.

[Tsyal Maktoyu]

For LIGO, I wonder if certain relativistic effects might be the cause for the lack of results. I think it can be described by length contraction, in which an object appears to shrink (as seen by an outside observer) at close to the speed of light, in the direction of travel. Why would take a while to explain, so I'll leave it at. Though as I've said, this is only relative to an outside observer, as the observer traveling at close to C would not experience the effect. With that said, I'm sure a similar length-distortion effect if space time changes are a result of gravity shifts rather than speed. Which would mean that if the entire system is effected by a wave at the same time (including detector), the effect would not be seen by the detector. One would need to change the location of the detector, but how, I'm not sure.

I think you and I are on the same page, if not the same paragraph.

This, I think, is why gravity wave detectors have two arms that are orthogonal to each other. Imagine a gravity wave propagating past a detector. The direction of travel of the wave will form an angle with one arm of the detector. It will form an angle +/- 90 degrees with the other leg. This should cause the effect of the gravity wave to be 'experienced' differently by each arm. While immeasurable in one arm alone, it is measureable as a differential between the two arms. In an ideal case, the gravity wave would strike one arm completely parallel to it, and the other leg perpendicular to it. The perpendicular arm would experience spacetime expansion and contraction on it's length, while the other arm would experience such effects only across its section. The former arm would not see any changes if refernced to itself. But if compared to the arm that was not experiencing much of the spacetime effects, you would see a difference in propagation velocities of the laser beams in the two arms.

Now, maybe there is something about gravity waves we don't understand, that would affect both arms in such a way that you would not be able to measure the effect with an electromagnetic method, such as laser propagation time. So although we can see other effects of gravity waves in the distant universe, we will never measure one with this kind of apparatus.

Well that's what ideally should happen, but I guess the results say otherwise. Maybe it's time to maybe put something like this in space, outside of Earth's gravity well in space time. Maybe a Lagrange point (spelling?) or another spot with flatter space time.

Edit: Just got an idea for a wave detector, and it relates to the concept of supercontinuity and length contraction. It's similar to LIGO, but is in the shape of a + instead of an L. The problem I see with LIGO is that it attempts to make interference with beams moving in one dimension (in the arms), and that the beams only interact again, after the fact, in the vertex, and after the wave somehow forces the beams out of whack. According to relativity, no effect should be seen, as the light beams will both be on the wave along the same dimension, and from their PoV, space time is flat. In the end, no sum change.

My detector has two beams DIRECTLY interacting in TWO dimensions. Two beams interacting 90 degrees, at X frequency, will under normal circumstances, produce consistent interfered beams in both beam tubes. If a wave passes into the system, the beam of one tube will experience the wave differently than the beam of the other, meaning that the red/blue shift of each will be different than the other, and because they won't be interfering in one dimension, it might be possible to "beat" relativity, so to speak, and create an effect of supercontinuity in the interacting beams, thus creating a sum, observable frequency change in one or both of the beams (the strongest being likely visible in the beam traveling most parallel to the wave, thus experiencing the least wavelength shift in the original beam and hopefully being able to capture the most of the shifted photons in the opposing beam). Detectors are also at the ends, and not the center point.