These types of calculations are very interesting and useful, and IMO they should be used to either falsify or verify LCDM. I would say that *if* we knew from controlled laboratory experimentation that exotic forms of matter definitely exist in nature, then such a technique might be very useful in estimating the ratio of each type of matter (dark/baryonic) that might actually exist in space.Hi Michael:
The following is another, and a more clearly written, discussion of the relationship between Deuterium and dark matter.
During the formation of helium nuclei, perhaps only one in 10,000 deuterons remained unpaired. An even smaller fraction fused into nuclei heavier than helium, such as lithium. (All the other familiar elements, such as carbon and oxygen, were produced much later inside stars.) The exact percentages of helium, deuterium and lithium depend on only one parameter: the ratio of protons and neutrons--particles jointly categorized as baryons--to photons. The value of this ratio, known as n (the Greek letter eta), remains essentially constant as the universe expands; because we can measure the number of photons, knowing n tells us how much matter there is. This number is important for understanding the later evolution of the universe, because it can be compared with the actual amount of matter seen in stars and gas in galaxies, as well as the larger amount of unseen dark matter.
For the big bang to make the observed mix of light elements, n must be very small. The universe contains fewer than one baryon per billion photons. The temperature of the cosmic background radiation tells us directly the number of photons left over from the big bang; at present, there are about 411 photons per cubic centimeter of space. Hence, baryons should occur at a density of somewhat less than 0.4 per cubic meter. Although cosmologists know that n is small, estimates of its exact value currently vary by a factor of almost 10. The most precise and reliable indicators of n are the concentrations of primordial light elements, in particular deuterium. A fivefold increase in n, for example, would lead to a telltale 13-fold decrease in the amount of deuterium created.
Since we have ample evidence to suggest that the baryonic mass estimates of galaxies that we've been using are seriously innaccurate, I'm hesitant to leap to any conclusion which constricts me and *obligates* me to any specific ratio of exotic matter in the universe. How do I even know for certain that exotic forms of matter even exists at all from uncontrolled observations in space and galaxy mass estimates which are not correct? If we start assuming that a very specific ratio of exotic matter to normal matter *must* exist and therefore we *assume* that exotic forms of matter *must* exist, I think it's very easy to get lost in 'dogma' and locked into a particular dogma rather than being up front about the current limits of our technology and the serious and numerous problems in our baryonic mass estimation techniques.
If exotic forms of matter do not exist in nature, then LCDM should be falsified and die by that same prediction sword if it cannot explain the elemental abundance figures without exotic 'fudge factors".
Let's take a close hard look at the various laboratory experiments over the past decade. We have literally spent billions of dollars/euros "testing" the standard particle physics model at LHC, and thus far it's performed flawlessly. We've also tested several non standard particle physics models like SUSY theory, and they've come up empty at LHC. Not a single 'sparticle" has been observed, and LHC is now operating at close to it's maximum energy state. We've also spent many millions of dollars at LUX and PandaX and Xenon100 and now Xenon1T experiments which have all tried and failed to find direct laboratory evidence for exotic forms of matter, The results to date of every single lab experiment related to exotic matter have all been all negative.
If you set aside any need for creation (of matter) concepts for a moment there is no evidence that exotic forms of matter exist. Hannes Alfven for instance proposed a cyclical type of "bang' theory that was based upon matter/antimatter interaction. His theory did not require that all matter in the universe was ever required to condense itself to a single "point' before matter/antimatter interactions began to cause it to expand again. It may have only contracted to say 10 percent of it's current size before expanding again. In such a scenario, the elemental composition of the universe today might have more to do with the original elemental composition prior to 'contraction' and less to do with with anything related to the annihilation or 'expansion' process.
A couple of other tidbits of information that may be noteworthy here are the fact that the various stellar underestimation problems which I cited earlier would tend to suggest that a significant portion of the 'missing mass' from that 2006 Bullet Cluster lensing study is likely to be found inside of stellar mass, and probably also in neutral hydrogen gas that would tend to "pass on through" a galaxy collision process. Because of various EM influences, the hot plasma halos around galaxies are more likely to "collide" in cluster collisions, but the distance between stars in any given galaxy minimize the likelihood that stars would actually physically collide very often in a 'collision' process. That type of dense matter would tend to pass right through, as would neutral atoms of dust and non plasma. The hot plasma halo tends to perform more like a "fluid" and it would be more inclined to interact and collide.
The current standard solar model predicts stellar abundance figures which are based upon the concept of 'fast" solar convection processes which presumably keep heavier elements like Nickel and Iron mixed together with wispy light elements like Hydrogen and Helium, from deep within the sun at the base of the convection zone, all the way up to the surface of the photosphere.
SDO measurements in 2012 revealed that contrary to 'jet speed' convection predictions of the standard solar model, SDO measured something closer to walking speed convection inside of the sun. How that "slow" convection process might affect stellar abundance figures is anyone's guess, and I would therefore hate to obligate myself to any specific elemental abundance figures at the moment.