Meet a theoretical particle physicist

  • 26 April 2022
  • 5 minutes

Gonville & Caius College Fellow Dr Tevong You is a theoretical particle physicist, who answered our questions about his research.

Tell us about your research:

I work on new models of physics beyond the standard model. The standard model of particle physics is an incredibly successful theory. It describes everything in the known universe that we can see and even things that we can’t see. But we know there must be something beyond the standard model. My research is trying to come up with new theories that extend the standard model to try to understand outstanding problems in fundamental physics.

Professor Stephen Hawking, a Caius Fellow for 52 years, was the world’s most prominent physicist. How much of an influence was he on your choice of subject?

He was a big inspiration in physics for many physicists. The people who understand his physics appreciate what he discovered. He was also very inspiring as a human being and he was also a very successful science populariser, who wrote clearly and in an inspirational way to the public. His impact did have some influence on me. Although I have to admit that, like many people, I didn’t understand A brief history of time when I first read it at school, it did get me excited about all the various ideas in physics. Even if it isn’t the first popular science book I'd recommend, he does write in a beautiful way and that was an inspiration to me. I did have a few interactions with him at Caius. I rebooted his computer at formal dinner once, when it crashed and everyone was frantically trying to fix it.

A man in a dinner jacket crouching next to a stone bearing the name of Professor Stephen Hawking

Dr You by the Stephen Hawking Memorial stone in Caius Court

Why is your research important?

I like to say only by understanding the cosmos can we appreciate our place in it. It’s almost a tautology, but it’s true that we can only appreciate where we are in the universe if we know the size of the universe, if we know how special we are to even be here, given the way the universe evolved and the laws that govern it.

It's tremendously important to understand our universe, because it’s speaking to where we come from, what we’re made of, what the laws of the universe are, why they are the way they are. These are fundamental questions that attract a lot of attention to our field, because a lot of people are curious about these things. It’s not because it’s practical for technology, although it can be. It’s not because we want to make better phones or computers. It’s simply a deep – even in some cases spiritual – question about the fundamental nature of the universe that we live in.

The utility of fundamental physics to me is, first and foremost, about seeking answers to big questions that are grounded in observation and experiment. Then, as a side-effect, the entire scientific process of seeking these answers is in itself very useful for society, very practical in terms of the spin-off technologies, in the training of a new generation of people who are attracted by fundamental science, who get training in scientific reasoning, data analysis, machine learning, working in small teams or large international collaborations. This whole industry is accelerating a culture of science and technology where people go off and invent the internet, build start-ups and use their scientific knowledge and training in other industries. What we get is much more than we put in.

Please can you explain your research in more detail.

My early research focused a lot on the Higgs Boson discovery of 10 years ago. The Higgs discovery was a monumental achievement in particle physics. It was essentially the last particle that completed the standard model, but finding the Higgs wasn’t just a case of collecting them all and having the final missing piece. The Higgs Boson is a fundamentally new and different type of particle to the usual matter and force particles that we know of in the standard model. The Higgs Boson has a special role in giving mass to all the other particles and it’s the only elementary spin-zero particle of its type; the others being spin half and spin one, matter and force particles that we’re more familiar with.

When the Higgs was discovered at CERN (European Council for Nuclear Research), my early research was to take the data the experimentalists had measured and ask ‘is this a standard model Higgs or is it a Higgs beyond the standard model? Could it even be a Higgs impostor?’ When the 2013 Nobel Prize was awarded to Englert and Higgs they cited in the scientific background document my paper at the time, quoting the conclusion that said 'Beyond any reasonable doubt, it is a Higgs boson'.

More recently I’ve been doing some research on how early universe cosmology could help explain the perplexing value of the Higgs mass. It turns out to be much lighter than naive expectations in a way that suggests new physics mechanisms and associated new particles to solve the problem. My research has focused on why we haven’t seen the other particles we expected to see and how we can solve these problems in a different way given the typical solutions we expected to show up haven’t shown up in experiments yet. This is where this cosmological direction comes in. Maybe the reason we haven’t seen these particles is because they’re much heavier, but the Higgs mass is light because some other type of Higgs-like field evolved in the early universe making the Higgs light in a dynamical way.

Going forwards I’m also helping to build the physics case for the next generation of colliders, beyond the LHC (Large Hadron Collider). To seek more definitive answers we have to go to even bigger colliders than the ones we have.  Smashing things at even higher energies and collecting even more precise data extends the boundary of our experimental knowledge about the building blocks of the universe; only in that way can we keep learning about nature at smaller and smaller scales.

Dr You is also a Branco Weiss Fellow - click for his profile 

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