CPT asymmetry question, in regards to recent experiment@CERN

[relatively-uncertain]

Hi, I'm a high-school student, so it would be nice if someone could answer this question without a huge amount of terminology. I heard that recently at CERN at the BASE experiment, the magnetic moment of an antiproton (to nine places is the exact same as the magnetic moment of a proton..) I was wondering if there are any hypotheses on why this is; do antiparticles and particles behave differently at all? Are there any theories as to why there is baryonic asymmetry? And I have endeavored to consult more recently published sources (have been fruitless), apart from a few contemporary articles here and there. In one of the articles, I’m slightly confused with “All of our observations find a complete symmetry between matter and antimatter, which is why the universe should not actually exist,” says Christian Smorra, a physicist at CERN’s Baryon–Antibaryon Symmetry Experiment (BASE) Does CPT asymmetry really have this implication to the formation of our universe? I'm slightly confused with the entire concept of Baryonic Asymmetry and the scientific implications this has. Thanks so much!

 

[Orodruin]

I was wondering if there are any hypotheses on why this is; do antiparticles and particles behave differently at all?

Yes, they do behave differently, but there needs to be certain symmetries for the theory to be internally consistent. One such symmetry is CPT, which is changing the charges of all particles, makes a spatial reflection, and reverses the direction of time. This symmetry requires that the proton and anti-proton have the same magnetic moment.

Are there any theories as to why there is baryonic asymmetry?

Yes, there are several. However, the symmetries that you need to break in order to generate a baryon asymmetry is not CPT, but C and CP.

In one of the articles

This is not a proper reference as it does not give the actual reference. Note that forum rules require you to provide the actual reference. If you do not we have no way of checking the actual statements and cannot judge what it is actually saying. Misunderstandings can arise from several sources, from the reference being bad to your interpretation of it being bad. We also cannot solve your problems by guessing what the reference states. Therefore, please provide the actual references instead of saying "I read somewhere that ..."

 

[relatively-uncertain]

Thank you for your reply...sorry I didn't source it but here it is:
https://cosmosmagazine.com/physics/universe-shouldn-t-exist-cern-physicists-conclude

Thanks so much again

 

[Orodruin]

Taken at face value, the statement is wrong. What the magnetic moment tests is CPT symmetry. What is necessary to create a matter-antimatter asymmetry (among other things) is breaking of C and CP violation. There is known CP violation in the quark sector through the phase in the CKM matrix. However, this is not large enough to explain the baryon asymmetry. The original article also clearly states that what they are testing is related to CPT.

 

[mfb]

As simplified description: Finding an unexpected new source of CP violation would mean we habe to adjust or extend our formulas - that would be great. Finding CPT violation (what BASE is looking for) would mean the way we write down formulas itself needs to be changed - that would be amazing.

 

[relatively-uncertain]

Thanks again for your answer! So, just to clarify, baryonic asymmetry would require asymmetry in C and CP? The CERN test was the magnetic moment, and is only a test for CPT symmetry. So the only thing they have confirmed is that there is no asymmetry in CPT? Please tell me if I have made any misunderstandings.
Have there been any tests for C and CP violations yet? Thanks!

 

[Orodruin]

Have there been any tests for C and CP violations yet? Thanks!

As I said, we have already discovered those, but not at the level that would explain the baryon asymmetry.

 

[mfb]

So the only thing they have confirmed is that there is no asymmetry in CPT?

At least not one larger than the uncertainties of the measurement.

C violation is very large in the weak interaction, but P violation is very large ("maximal") as well, if you combine them you get CP where all violations seen so far are very small.