Physicists Test Symmetry Principle With an Antimatter Beam

Hugh Pickens DOT Com writes "Jon Butterworth has an interesting article at The Guardian about the idea of standpoint-independence in physics and the absence of 'privileged observers.' The ASACUSA experiment at CERN plans to make a beam of antimatter, and measure the energy levels as the beam travels in a vacuum, away from the magnetic fields and away from any annihilating matter. The purpose of the experiment is to test CPT (Charge/Parity/Time) inversion to determine if the universe would look the same if we simultaneously swapped all matter for antimatter, left for right, and backwards in time for forwards in time. In string theory for example it is possible to violate this principle so the ASACUSA people plan to measure those antihydrogen energy levels very precisely. Any difference would mean a violation of CPT inversion symmetry. Physicist Ofer Lahav has some interesting observations in the article about how difficult it is these days for physicists to develop independent points of view on cosmology. 'Having been surrounded by a culture in which communication is seen as generally a good thing, this came as a surprise to me, but it is a very good point,' writes Butterworth. 'We gain confidence in the correctness of ideas if they are arrived at independently from different points of view.'

A good example is the independent, almost simultaneous development of quantum electrodynamics by Richard Feynman, Julian Schwinger and Sin-Itiro Tomonaga. They all three had very different approaches, and Tomonaga in particular was working in wartime Japan, completely cut off from the others. Yet Freeman Dyson was able to prove that the theories each had provided for the quantum behavior of electrons and photons were not only all equally good at describing nature, but were all mathematically equivalent — that is, the same physics, seen from different points of view. Whether we are using thought experiments, antimatter beams, sophisticated instrumentation, or sending spaceships to the outer solar system, Butterworth says the ability for scientists to loosen the constraints of our own point of view is hugely important. 'It is also, I think, closely related to the ability to put ourselves into the place of other people in society and to perceive ourselves as seen by them — to check our privilege, if you like. Imperfect and difficult, but a leap away from a childish self-centeredness and into adulthood.'"

Re:Feynman tutored me in QM at Caltech

[Artifakt]

Here's a nice video of Dr. Feynman explaining why a mirror works the eay it does - be thou unstymied!

https://www.youtube.com/watch?... [youtube.com]

Re:Feynman tutored me in QM at Caltech

[wonkey_monkey]

t turns out that an antiparticle going back in time is exactly the same as a regular particle going forward in time.

I thought determining the truth of that is what this experiment is all about.

I am STILL stymied by a question he asked once:

"Why does a mirror reverse left-and-right but not up-and-down?"

It doesn't. It reverses back-and-front.

Hold up a print-out of writing on paper you can see through, so that you can read it. Do so with a mirror beyond the paper, and you'll be able to read the writing (through the back of the paper) just fine.

Re:Culture Dogma

[Gavagai80]

Your example defeats you nicely. Most scientists of the early 20th century (including Einstein and Eddington) had a strong belief in a basically static universe that was infinite in time, because that was the elegant solution with philosophical appeal. It took the indisputable evidence of the red shift to convince them that there was in fact a big bang which was the beginning of the current order, against their natural inclinations.