Science Forums 2

[CraigD]

Originally Posted by Hasanuddin

If the AEGIS project categorically shows that matter and antimatter gravitationally attract, then game over. I’ll collect my marbles and leave the playground. The Dominium model is a falsifiable construct. The central premise is its cornerstone, dislodge that and everything falls.

Its falsifiability is an important feature, as, IMHO, it makes the Dominium model scientific, regardless of any criticism of it.

It’s also fortunate that the model is being discussed at the same time that the first time in the roughly 80 years that antimatter has been known to science, experiments to directly and unambiguously test its central premise – that antimatter and matter are gravitationally repulsive – is possible, and nearing completion by the AEgIS collaboration.

Originally Posted by Hasanuddin

There are two other outcomes that could come out of AEGIS, and/or other current experiments seeking to discover the gravitational relationship between matter and antimatter…

I think Hasanuddin’s list is too small, missing a major class of possible result - the one, in fact, on which much of the effort of the experiment’s design and engineering is focused (begging pardon for the physics experimentalist pun):

4: Gravitational attraction is observed, but with a lower apparent gravitational constant () that observed for matter-to-matter attraction.

The planned AEgIS experiment should be able to detect variations in of about 1%.

My guess is that it’ll reveal either outcome #1 - No difference in , or #4 – A very small reduction in .

If outcome #4 is observed, an explanation might be that antimatter and matter gravitationally repel, but only for particles that are distinguishable from their antiparticles – that is, in conventional particle physics terms, for fundamental particles what are not their own antiparticles. If this is the case, then for the reasons I discussed in post #63, the observed value of should be about 97.3% of usual, a difference that should be detectable by the experiment.

Originally Posted by Hasanuddin

3: Inconclusive results. This is the most dreaded of outcomes.
…
Margins of error could easily be so wide that nothing significant is shown.

I don’t believe we need worry about this outcome, because CERN’s antihydrogen production ability has become very reliable, and its instrumentation is simple, reliable, and accurate to its stated precision. As with any gravitational deflection experiment involving very small particles, the major threats to this experiment appears to be uncontrolled charge, because the electromagnetic interaction of the particles involved are so much stronger than their gravitational. A failure of the experiment’s beam to consist of neutral antihydrogen, but instead contain many ions, would ruin it.

Originally Posted by Hasanuddin

Honestly, I’m getting tired of the uncertainty.

I can’t think of anybody who likes large margins of error in experimental setups. The task for an experimentalist is to design experiments and build apparatus to minimize it - one of the most demanding jobs on Earth.