"The HiggsBoson: 10 Years On" -- An Interview with Miha Muškinja Ph.D. of Lawrence Berkeley Labs

By Sabine Fuchs, Katherine Branson School

One of the most complex discoveries in particle physics, the Higgs boson, recently celebrated its 10th anniversary last July. Miha Muškinja, who is originally from Slovenia, is a postdoctoral researcher in physics at Lawrence Berkeley Lab. Muškinja worked on the ATLAS experiment, which announced the discovery of the Higgs boson, at the Large Hadron Collider (LHC) at CERN near Geneva, Switzerland. Recently, he moved to Berkeley, California, where he specializes in analyzing the properties of the Higgs boson, in addition to working on algorithms and infrastructure to process data by the LHC. In March of 2023, Muškinja presented The HiggsBoson: 10 Years On at Marin Science Seminar and explained what the Higgs boson is, its significance, and its discovery in 2012. 

Q1: How did you become interested in particle physics?

During elementary and high school, I had a strong fascination with mathematics, physics, and chemistry. It became evident early on that I would pursue studies in one of these fields. On July 4th, 2012, I watched the live stream of CERN's announcement regarding the discovery of the Higgs boson, which was delivered by Fabiola Gianotti, the spokesperson of the ATLAS experiment at that time and now the Director General of CERN. This event sparked my interest in particle physics and solidified my decision to study physics with the goal of becoming a scientist at CERN. Although it seemed like an impossible task at the time, my dream came true six years later when I began my Ph.D. in particle physics with the ATLAS experiment at CERN.

Q2: What advice would you give someone interested in pursuing a career in particle physics?

The theoretical framework of particle physics, known as the Standard Model, is built upon a complex mathematical framework called Relativistic Quantum Field Theory (QFT). This theory is among the most difficult you will encounter at any university, so it is crucial to study diligently. You will need to acquire a high level of understanding in both physics and mathematics to be comfortable with the Standard Model. Additionally, programming skills are highly important in particle physics, as in many other research fields today. I would recommend learning programming languages such as Python and C++. Lastly, seek out a university or college that has a particle physics group. During your undergraduate studies, try to engage in research projects related to particle physics. This will provide you with a glimpse into the life of a particle physicist and assist in determining if this career path is the right fit for you. Lastly, keep in mind that the field of particle physics is highly competitive. Only a tiny fraction of particle physics students will ultimately become professors at a university of research scientists at a laboratory such as CERN or LBNL. However, there are many other career paths that you can pursue with a degree in particle physics. The skills you acquire through particle physics research are highly transferable and sought after by employers.

Q3: How would you explain the Higgs Boson to someone with no prior knowledge?

Let's begin with the Higgs Field, which is responsible for imparting mass to certain elementary particles. The Higgs Boson is a particle associated with this field. At CERN's Large Hadron Collider, we create Higgs Bosons by colliding protons at very high energies, causing localized excitation of the Higgs Field. This excitation manifests as a particle, the Higgs Boson, which we can measure and study.

In the immediate aftermath of the Big Bang, when the Universe came into existence, there was no Higgs field (although technically it was present, its value was zero on average). All particles moved at the speed of light. As the Universe expanded and cooled down, the Higgs field suddenly acquired a non-zero value everywhere in the Universe in a process called Electroweak Symmetry Breaking. Some particles began interacting with this Higgs field, which slowed them down (e.g., electrons). The more they interacted, the slower they moved. This interaction is what we refer to as mass. Particles that do not interact with the Higgs field, like photons, continue to travel at the speed of light and have zero mass.

Q4: Are there any controversies surrounding the Higgs Boson? If so, what is your perspective on them?

One of the major mysteries surrounding the Higgs Boson is its mass. Despite being the second heaviest known elementary particle, it remains relatively light. Naively calculating the Higgs Boson's mass using the Standard Model would yield a value 16 orders of magnitude larger than the measured value. This conundrum is referred to as the Hierarchy Problem. Additionally, the small mass of the Higgs Boson leads to other particles being very light as well. Consequently, gravity appears incredibly weak compared to other fundamental forces. The electromagnetic force between a magnet and a paperclip is stronger than the gravitational force between the entire Earth and the paperclip. This significant disparity remains unexplained. However, it serves as a driving force that keeps us motivated and excited to continue studying the Higgs Boson. We are certain that there must be something beyond the Standard Model, which we can explore through experiments like the Large Hadron Collider at CERN.

The ATLAS experiment at CERN

Q5: What impact does expanding our knowledge of particle physics have on the scientific community and our daily lives?

Expanding our knowledge of particle physics has profound implications for both the scientific community and our daily lives. Here are some of the impacts.

• Fundamental understanding of the universe: Particle physics seeks to comprehend the fundamental building blocks of the universe and their interactions. This knowledge enhances our understanding of the origins and evolution of the universe, as well as the laws that govern it.

• Technological advancements: Particle physics research often leads to breakthroughs in technology. The development of new particle detectors, accelerators, and computational techniques for data analysis frequently have applications beyond particle physics. For example, medical imaging technologies like positron emission tomography (PET) and computed tomography (CT) have their roots in particle physics research. Notably, the World Wide Web was invented at CERN to facilitate communication among particle physicists, showcasing the transformative impact of particle physics on technology.

• Computational and data science: Particle physics experiments generate vast amounts of data that necessitate sophisticated computational techniques for analysis. Addressing these challenges has propelled advancements in data science, machine learning, and high-performance computing, benefiting various fields.

• Inspiration and education for future generations: The pursuit of fundamental knowledge and the discovery of new particles or phenomena inspire interest in science and motivate young minds to pursue careers in STEM (Science, Technology, Engineering, and Mathematics) fields. Many students involved in particle physics experiments ultimately venture into diverse fields such as medicine, finance, or data science. The skills acquired through particle physics research are highly transferable and sought after by employers.