Particle Physics and Basic Research at CERN
Particle Physics and Basic Research at CERN
  • Dr. Baek Yong-wook
  • 승인 2019.06.13 13:14
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▲Deputy Team Leader for ALICE-004104 /
▲Deputy Team Leader for ALICE-004104 /

1. LHC and ALICE
The LHC (Large Hadron Collider) is a powerful ring-shaped particle collider that lies across the border of Switzerland (Geneva) and France. It is 27 km in circumference and can collect data from collisions at the highest energy in the world since 2009. The LHC has contributed to the discovery of the Higgs boson from proton-proton collisions, a particle whose existence was predicted by the standard model. Currently, research on the evolution of the universe after the Big Bang are being carried out by the ALICE (A Large Ion Collider Experiment) collaboration. QGP (Quark-Gluon Plasma) is the state of matter believed to have existed after one-millionth of a second after the Big Bang. The ALICE experiment checks the QGP formed when lead-lead ions collide and uses this information to understand what the universe looked like after the Big Bang.
The LHC focuses on the research in pure physics; however, particle accelerators used for applied physics also exist. An example is the PLS (Pohang Light Source). The PLS, as can be referred from the name, uses high-energy (X-ray or microwave) light emitted by spinning electrons in a ring for research such as non-destructive examination. Also, the currently under-construction RAON (Rare isotope Accelerator complex for ON-line experiment) can shoot heavy nucleons (uranium) at a target to form heavier and rarer isotopes, which is used to develop new material or cure cancer.

2. Studies at the LHC
I have been researching at CERN (The European Organization for Nuclear Research) since 2001. I have participated in the R&D of particle detectors which identify particles using ToF (Time-of-Flight) methods since, and I work as the run coordinator of the ALICE muon spectrometer during data analysis and LHC operation. The ToF detector R&D is a collaboration with the ALICE research team of Italy and aims to create a detector with a better temporal resolution than 100 ps. Due to the detector’s superb performance, it is modified and used in a variety of experiments such as in research to convert greenhouse gases into eco-friendly gas, which is being carried out by myself and other groups as well.
In addition, I have been researching about global polarization of lambda baryons from lead-lead collision data analysis.  When a deflected collision happens among heavy ions, the nucleons inside instantaneously roatates strongly to form lambda particles, whose spins are aligned in the direction of angular momentum. Then the lambda particles are likely to show up in the direction of spin. My research showed that polarization decreased as the collision energy increased and will be negligible at LHC energy level. A small polarization value has been measured, which conforms to the expectations, and the value is believed to be non-existent if measurement error is taken into account. This result will soon be published in a paper.

3. A Need for National Support on Basic Science
A lot of people who visit CERN ask me these questions: “Why should we continue to carry out costly basic science research?” “How much value is created through the research at CERN?” “Wouldn’t it be better to invest the money in applied science research which would more certainly benefit the nation’s economy?” When I first encountered these questions, I was quite disturbed because I could not think of a suitable answer. I wondered whether economic value was something that should be considered when studying basic science. If you take into consideration the rapid economic growth of our nation, things get clearer as to why someone would ask such a question. Set aside the short-term success that burden those who run the country, and the answer becomes quite simple. If we do not lay out the cornerstone of basic science, we would not have something to build upon; we would need to purchase the necessary technology from other countries.
Dr. Sergio Bertolucci, who served as the deputy director of CERN, emphasizes that basic and applied science are equally important, exclaiming, “Basic science makes candles into lightbulbs; Applied science helps make better candles.” I think this is a good example that highlights the significance of basic science. It is true that applied science research can produce more short-term achievements. However, applied science research can be carried out by private companies based on their commercial needs; basic science research is in desperate need of long-term state-level support for it to even survive.

4. Advice to Students Who are Intereste

d in Accelerator Related Fields
If I were to give one special advice to students who wish to take part in particle physics experiments, I would like to assure them that they are the front-runners of the nation’s basic science and they should be proud of it.
If you ask students why they are researching or aiming to continue their studies in the field of basic science, the answer is quite simple. They simply want to know more about the topic, and the process of doing so is fun. This basic, yet fundamental reason is the driving force behind all those creative research and ideas. If studying basic science suits your aptitude and you are willing to exert your full ability, there will be no doubt that one day your research will bring wealth and fame to the nation.
Particle physics in our country is quite active with the government funding more than 4 billion KRW, and about 150 people are actively researching in ALICE of LHC, the CMS (Compact Muon Solenoid)  experiment, and GRID computing at CERN. Ph.D. students are given a chance to finish their doctoral dissertation at CERN with 2 to 3 years of support. Master’s students can also have a chance to experience research life at CERN for a short period of time. I believe that such experience at global research institutes will greatly benefit the future life of students, and will consequently contribute to raising the overall level of basic science research.