Antimatter

To understand antimatter, Let's quickly revist my previous post where I defined what an antiparticle was. For those of you just joining, I'll quickly outline it again and also add some useful information.

An antiparticle is similar to a particle in that it has the same mass and spin. The difference is opposite charge.
The famous example, the antiparticle of the electron is the antielectron, better known as the positron.

When particles and antiparticles collide, they annihilate, however, they don't just simply vanish. Instead, due to conservation of energy and momentum, they annihilate to create different particles. In the case of the electron and positron, they annihilate to produce two identical gamma ray photons both with an energy of .511 Mev/c^2 speeding off in opposite directions. Which is precisely the mass/energy of the electron/positron. Of course, the lifetime of the gamma ray photons are short lived. The lifetime of the positron is also short lived. This is due to 1) matter dominating the universe and 2) since all things are made of matter, it isn't very difficult or very long before a positron collides with an electron.



Above, is an image I found online outlining fundamental particles and their antiparticles. Of course they skip the gauge bosons. But I can outline them quickly and in a simple way.

Photon: due to its charge, it is its own antiparticle. "A photon is a photon is a photon" famous words of someones... but referenced from whom I heard it said, Professor Claire.

Z: Is also its own antiparticle.

W+: Its antiparticle is the W- boson.

W-: Its antiparticle is the W+ boson.

Gluon: the gluons are the more complicated guys. As it turns out, all gluons carry color flavors or rather, color charge. There are three types of color charges, red, blue and green. Therefore, there are three anticolor charges, anti-red, anti-blue and anti-red. Color charge of gluons involves a more in depth explanation and understanding. The following link, explains it very well and way better than I can.. Theory: Color Charge

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Note: I just wanted to point out an important thought regarding anti-hadron configurations. We know that the proton (which is a hadron and Baryon) is made up of two up quarks and one down quark. The correct way to think about an antiproton would be as follows: two anti-up quarks and one anti-down quark.

(the WRONG way would be to say two down quarks and one up quark. That would actually be a neutron!)

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Now that we know what antiparticles are, Let's talk about antimatter! For starters, did you know that certain radioisotopes are natural positron emitters (specifically, Beta-plus decay)? This means that these radioisotopes are emitting anitparticles during their decays. Interesting enough, recall what I mentioned above regarding the fact that we have only known about antiparticles for approximately 85 years? Well, this indicates that even though the periodic table was practically fully developed and radioactive materials had already been discovered, we had no idea that radioactive decays involved antiparticles.

With that being said and tons of new particles being discovered, it is no wonder why particle physics boomed. I read somewhere, that "The next people to discover a new particle should be fined rather than given award money."

Efforts are currently being made to analyze the properties of antimatter, more specifically antihydrogen (An antiproton and a positron), and to trap/contain it. Current projects such as ATHENA, ALPHA and ATRAP at CERN have pioneered cold antihydrogen, accurate hydrogen spectroscopy, first observed hot antihydrogen atoms and own the record for trapping anti-hydrogen for the longest amount of time, less than 16 minutes the last time I checked, which was just last year. (I may do an additional post on traps and how antiparticles are contained if I have time or if someone would really like to hear about it.)

I sometimes allow myself to envision a periodic table of antielements. A professor of mine told me that was silly. However, the funny thing is, I'm not the first and definitely will not be the last. Charles Janet had this vision long before I did, circa 1929. Before the positron was even observed.

Before I conclude this post, I would like to propose some questions for everyone to think about and perhaps discuss or comment on. :)

1) Why the apparent asymmetry of matter and antimatter in the visible universe?! (Look up Baryogenesis)

2) "Antimatter may exist in relatively large amounts in far-away galaxies due to cosmic inflation in the primordial time of the universe. If antimatter galaxies exist, they are expected to have the same chemistry and absorption/emission spectra as normal-matter galaxies, and their astronomical objects would be observationally identical, making them difficult to distinguish."

How then can we confirm whether or not they do or don't exist?!

3) What are the main techniques in trapping antimatter and more importantly, how can they be improved?!

4) Does antimatter fall up or down via the force of gravity?!

(I had so many questions but now cannot remember them all. Don't worry, when they come to me, I will update this post. Perhaps 5 is more than enough!)