A couple of weeks ago in weekly roundup 53 I talked about an experiment to look at the energy levels present in antihydrogen and compare them to those found in regular hydrogen. Of course no difference was found as no difference often is. It seems that matter and antimatter are completely identical up to the greatest experiments and highest resolutions we can manage. Yet when looking out at the universe there is clearly significant difference as matter is here and antimatter isn’t. The most reasonable explanation is that this is caused by a minute, currently unobservable, difference that when multiplied billions upon billions of times adds up to the the large scale difference observed.
In order to try and find the differences the options are to either keep adding more and more antiparticles to the same system and comparing it to the matter system. For instance comparing anti helium to regular helium followed by the two lithiums and continuing until a difference is seen in some larger atom. The other option is to keep advancing our measurement techniques so that greater precision can be achieved. The first method is difficult as building antiatoms is very difficult as complete isolation is needed. The second is quite practical but eventually our technology will reach a limit where progressing isn’t physically possible and if the discrepancy has not been located we’ll be kind of stuck.
In the end a combination of both methods is used, my previous post highlighted experimenting on antihydrogen and this paper is on an improvement of measurement techniques. In particular the magnetic moment of the antiproton caught in a Penning trap (a kind of containment for charged particles with two positive and two negative plates). By minimising any external magnetic fields (hoping that the period of the Earth’s magnetic field will cancel) the magnitude of the magnetic moment of the antiproton was found with six times the precision of any previous experiments.