Day 2: Katie, Seth Zenz and the ATLAS Experiment

Hey World!

Now that you have seen some of my pictures from my trip to Geneva, Switzerland and to CERN itself, I will continue to describe my days at the LHC.

DAY 2:

I arrived at the CERN Reception area at 10:00 am. The first order of events was to sit down with Katie and chat with her about the upcoming week. I discovered while enjoying a tea at the cafeteria with her, that Katie had only a vague idea of what I was doing at CERN. Then, of course, I remembered. I had only e-mailed her telling her that I was interested, and after several brief communications, the entire trip had been planned. Yes, of course, Katie knew that I had been a finalist for an award at school and had eventually been sponsored to travel to CERN, and she knew that I had taken one year of Physics at Andover, but as to why I had chosen the LHC as a project to study or what else I was interested in...she had no idea. So, during this morning chat, Katie and I exchanged our personal histories and learned about how both of us had found our way to that small tea table in that cafeteria. I include this description merely because it demonstrates how much the people at CERN wish to spread knowledge about the LHC. Amazingly enough, even though I was virtually a stranger to Katie, she was willing to take significant chunks of time out of her busy schedule to teach an interested student about the LHC. In fact, everyone I spoke to at CERN had that same attitude. They were excited about teaching someone who was willing to listen, and even more excited about the prospect of my attempting to increase interest and awareness about the LHC at home and at Andover.

This conversation with Katie allowed me to probe into her personal story. Throughout the week as I spoke to the various scientists my favorite question to ask was the following: how did you decide to become a Physicist? The answers I received in response were varied...from "I didn't decide, I just WAS a Physicist" to "Oh, I was actually in the process of majoring in politics when I took a Physics class in college and suddenly decided to change my major." Katie's response to this question was that in college she had majored in...ready?...both Physics and dance! Just goes to show you that Physicists actually are real people who are interested in more things than solely Physics...much to my surprise. I think that somewhere in my head I had developed the notion that I was going to a place where mad scientists dwelled. Instead, I discovered a group of ordinary, yet at the same time, interesting people. It was never until I began to ask these Physicists about their job at CERN, or about the details of the LHC that they spoke in a language that was difficult for the average human to understand.

Seth Zenz, the graduate student with whom I sat at lunch on Day 2, was exactly one of these people. Seth seemed initially to be just a really great, personable guy. Yet, when asked about anything relating to Physics his entire face would light up with excitement. He is, after all, attempting to get his PhD in Physics from the University of California, Berkeley. 

I soon found out that Seth was willing to explain Physics to me for as long as necessary until I understood at least the underlying concepts of the LHC. Capitalizing off this realization, I grilled poor Seth with so many questions that I'm sure his lunch grew cold while he answered them. In fact, although he works on the ATLAS experiment, Seth is one of those rare people at CERN who has undertaken the pains of learning about the other experiments at the LHC as well, and figuring out how all these tests will work together to produce science. I could not have asked a better person to help me figure out the world of particle Physics.

It was from Seth, then, that I learned about the trouble the scientists were having explaining why photons have no mass and W and Z bosons have such large masses. It was also from him that I learned about quarks, and that in fact, the only three fundamental particles in the world are up quarks, down quarks and electrons. Apparently, neutrons and protons, which I had formerly believed to be fundamental upon my arrival at CERN, are actually made of up quarks and down quarks held together by strange particles known as gluons. So when the protons smash together in the LHC, it is not that the protons are really colliding, but that the quarks inside the protons are colliding. Finally and most remarkably, I found that aside from finding a Higgs boson, the particle predicted to create a Higgs field which in turn has been predicted to give particles mass, the LHC is also looking to answer questions about strange ideas such as dark matter, supersymmetry and antimatter.

But wait, you say, what exactly are you talking about? I guarantee that before this trip to CERN, I too had never heard of such things as dark matter, supersymmetry and antimatter. Thus, I feel I must take a break from this day summary to explain these bizarre concepts to you. I also must say before I begin these explanations that it took me the entire week, meetings with many different scientists and my own research to finally master these concepts enough to explain them to you simply. In other words, if you understand my following descriptions, which I expect that you will...absolutely go to your friends and family and brag about your brilliance in particle Physics, and then state your opinions (whether they be fake or real) on whether or not dark matter really is responsible for making galaxies spin faster than scientists predict mathematically, or whether finding why antimatter no longer exists in our Universe could lead us to some fascinating conclusions. Believe me, I tried such a tactic and my friends and family all wondered who had corrupted my mind. It was fabulous!

Anyway, I have lost track of myself. Now for a description of the three theories, dark matter and energy, supersymmetry and antimatter:

Dark matter and energy: According to LHC the guide, a booklet given to me by Katie to brief me on the LHC, scientific observations have led humans to believe that "all of the visible matter accounts for only 4% of the Universe." This unearthing fact leads us to the question--so what other forms of matter exist in the Universe? The answer is that there may be dark matter, which takes up about 23% of the Universe, and dark energy, which takes up about 73% of the Universe. According to theoretical Physics, dark matter could be responsible for making galaxies spin as faster than predicted by scientists, and dark energy may be involved in accelerating the expansion of the Universe. Both dark matter and dark energy have been confirmed to exist, and yet nobody knows what particles are responsible for them. Many theories do exist however, and the LHC hopes to tackle the mystery.

Supersymmetry: The theory of supersymmetry could lead us to the particles responsible for dark matter and dark energy. The idea of supersymmetry is that every small particle is accompanied by a much more massive super-partner particle. For example, all bosons would have corresponding  fermions, and more specifically, a quark would have a super massive partner particle known as the squark. According to LHC the guide, "if supersymmetry is right, then the lightest supersymmetric particles should be found at the LHC." Supersymmetry has not been confirmed to exist yet. 

Antimatter: Antimatter is the oldest theory of these three. It states that every particle has another particle that is exactly the same in every way except that it is oppositely charged. So, for example, a quark has an antiquark and an electron has a positron. When antimatter collides with matter, the two annihilate each other. Theoretically, at the beginning of the Universe, there were equal amounts of antimatter and matter. But, here is the catch...somehow, today only matter naturally exists, and antimatter has disappeared  (although it can be created). This fact is great for us humans because if matter and antimatter still coexisted in equal amounts, they would annihilate each other and life would never have been able to exist. But the truly daunting question remains: what happened to the antimatter? The LHC and two other CERN projects known as ALPHA and ATRAP hope to find the answer to this question.

How does all this relate back to my conversation at the cafeteria table with Seth? He first introduced these huge concepts to me of course. Although, I must say, I am not sure that I understood them all completely in the same way that I do now. In any case, through this lunchw with Seth, I had finally discovered that the LHC hopes to find the answers to many questions instead of just one question.

After my meeting with Seth, I went to meet Frank Taylor of MIT, who showed me around the ATLAS experiment (see pictures in the entry posted below). Again, I found myself traveling 90-100 meters underground into the so-called "Cavern" where the ATLAS detector is kept.

I must not have been able to keep the shock off my face when I saw the ATLAS detector for the first time. Yeah, I thought that the CMS detector was big when I saw it...but at that point, I had never seen ATLAS. The ATLAS detector is, in fact, the biggest of the four main detectors of the LHC, and boy could one tell! I think my mouth actually fell open at its size. And, just to throw in some cool facts about this part of the LHC, according to the website entitled The Atlas Experiment (see http://atlas.ch/what_is_atlas.html#4), "ATLAS is about 45 meter long, more than 25 meters high, and weighs about 7,000 tons. It is about half as big as the Notre Dame Cathedral in Paris and weighs the same as the Eiffel Tower or 100747 empty jets." I personally find such facts amusing...it seems the smaller the particles that Physicists are trying to measure, the bigger the machines that they must build.

The ATLAS detector basically does the same thing as the CMS detector--just while using a different style. However, both are looking for evidence of new, never-before-seen particles...and particularly for the Higgs boson. The benefit of having two detectors looking for the same material is that the data from one detector can be used to verify the data of another. Scientists do not like to rely on just one source, but instead on proofs that have themselves been proven to be true. On the down side, however, building two gargantuan detectors that work differently means spending much more money just to verify data. But hey, spending money is nothing compared to being able to prove that the Higgs boson really does exist.

So, that's it folks for a summary of Day 2 at CERN. Keep reading as I will continue to update this blog with descriptions of my third, fourth and fifth days visiting the LHC.

-Carolyn