Question: What sort of things have you discovered so far?

Matthew Malek answered on 17 Mar 2014:

Hi, Chezzie! I like this question — it gives me a chance to show off a bit! So thanks for stoking the ego! 🙂

In particle and astroparticle physics, we work in collaborations, as the experiments are too large to be run by one person. So most of my discoveries have been made as part of a team, though there is one that I’ll mention that I feel is mainly mine alone.

When I was a PhD student, I worked to help solve the long-standing “solar neutrino problem” that had been around since the 1960s — long before I was born! We managed to find the answer back in 2001. The “missing” neutrinos from the Sun had morphed to a different type of neutrino, via a process known as “neutrino oscillation”. It was the first time that I had been a part of a BIG discovery, and it felt AWESOME!

After getting my PhD, I starting working at the Fermi National Accelerator Laboratory, just outside of Chicago. There, I was part of the Pierre Auger Observatory (PAO), based in Argentina. The PAO was built to study the highest energy cosmic rays — subatomic particles from space having as much energy as macroscopic objects! There have been single cosmic rays found with as much energy as a tennis ball moving at about 100 miles per hour! We still have no idea about what causes these super-energetic particles! However, one of the big mysteries about then when I joined was whether there was a “cut-off” energy, above which they are basically switched off. (In technical terms, this is called the “GZK cut-off”, in case you want to Google it — “G” and “Z” and “K” are the initials of the people who first thought of it)

Anyway, it turns out that there is such a cosmic ray cut-off, and I was part of the effort to uncover this. Pretty cool, huh?

Next, I did work on a dark matter experiment. However, the mystery of dark matter continues, more than eighty years after “Crazy” Fritz Zwicky first came up with the idea, back in 1933. So I can’t take any credit for discovering any dark matter. At least not yet! (Ask again in ten years and I hope to give a more interesting answer!)

Right now, I am working on an experiment where we make a beam of one type of neutrino, measure it, then send it down into the Earth’s crust. It comes back out about 300 km later and we measure it again. By comparing the “before” and “after”, we can learn a lot! In 2011, we discovered the third (and maybe final) type of neutrino oscillation. This is similar to the one that explained the solar neutrinos in 2001; there are three “types” of oscillation. So I was part of discovering two of the three!

Thanks for the question! If you want to know more about any of these topics, do feel free to ask again!