My Summer Experience Taking my Candidacy Exam

by Jessica Brinson

My name is Jessica Brinson, and I have just begun my third year in the graduate physics program at Ohio State University. My research area is high energy experimental physics, and I have been doing research on the data collected by the Compact Muon Solenoid (CMS), which is one of the detectors for the Large Hadron Collider (LHC). The LHC is the largest and highest energy particle accelerator to date. It is located underground at a depth equal to a football field near Geneva, Switzerland. Two proton beams are accelerated around a ring and made to collide at the points where the detectors have been built so that we can study the results of the collision.

I finished all of my required classes at the end of the Spring quarter and took my candidacy exam during this past summer. The candidacy exam is a five week long process in which you are responsible for researching a given topic. Four weeks are devoted to writing a paper, and then you are given one week to prepare a presentation, which is given to four faculty members. My research topic was ‘The Discovery of the Higgs Boson.’ The Higgs boson is a fundamental particle that is responsible for giving mass to all of the other fundamental particles that have been observed, such as the electron and quarks, which make up the proton. I got my topic on July 29th, only three weeks after CMS announced their results showing evidence for the observation of a new boson that could be the Higgs. Since the excitement about the discovery was still fresh, it was the perfect time for the topic, but I was still nervous about taking my candidacy exam.

After receiving my topic, I spent two weeks doing nothing but reading everything I could find about the Higgs. I had heard many things about the Higgs boson throughout my undergraduate and graduate careers, mainly through my classes, but it wasn’t until I had to do the research for my candidacy exam that I fully grasped what the Higgs meant. While studying, I recognized many of the concepts that had been brought to my attention through the classes that I had taken, but it also revealed how much I didn’t know. I had learned why the Higgs is necessary in theory from my classes, but I had not done much research on how to detect it experimentally. The Higgs’ lifetime is so short that our detector is not able to see it directly; we can only detect the particles that the Higgs decays into and work our way backwards to figure out what actually happened. With over 40 million events a second, it was amazing to learn how the CMS detector worked to give us an idea of what happened in an event.

The next two weeks of my candidacy exam were spent writing my paper, which would end up being over 30 pages long. After two weeks of reading, I had to decide what the most important aspects were in the search and discovery for the Higgs. Writing everything down really solidified everything that I had been reading in my mind, and helped me in explaining the most important concepts in my own words. Many, many revisions later my paper was complete.

After I turned in my paper, it was time to prepare the oral presentation that I would give. The biggest challenge was condensing all of the material from my paper into a presentation that was only supposed to last 20 minutes. Even though your presentation is technically 20 minutes
long, the oral portion of your candidacy exam typically takes two hours. The faculty members who sit on your committee are allowed to interrupt with questions at any time. The oral presentation forces you to adequately explain concepts, but your committee is also interested in pushing you to the brink of what you don’t know. It is nerve wracking to not know an answer to a question during the oral exam, but it is expected that you won’t be able to answer everything. The committee wants to see how you pursue an answer to a question when you don’t immediately know the answer. This is a key portion of the scientific process because the research you do for your PhD will be a new question that does not have a definitive answer yet, and you are responsible for figuring out what the answer is. After a two hour talk, my committee conferred and decided that I had passed my exam!

Looking back on my candidacy exam, it was a stressful experience. However, your candidacy exam is meant to push your limits as a graduate student so that you are prepared for the research that you will have to do to obtain your PhD. Now that it is finished, I am really glad that I did it because it was a very rewarding experience. I learned so much from it and feel confident to pursue my PhD.

Here I am discussing my research with a fellow scientist.

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About Jessica Brinson

I am from Saint Joseph, Louisiana, and got my bachelor’s degree from Louisiana State University. My undergrad research was dedicated to neutrino physics related to Tokai to Kamioka (T2K). I now attend graduate school here where I do research for Chris Hill for CMS at the LHC.

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