“Multiculturalism” isn’t just a buzzword for ATLAS, it’s a way of life. With members of over 90 different nationalities – spanning every populated continent – ATLAS is a cultural experiment as much as it is a scientific one. 

The ATLAS Around the World series invites you to meet people from every nationality represented in the collaboration, to gain an insight into the individual journeys that brought them to particle physics. All are from very different backgrounds, but share the common goal of understanding our universe.

ATLAS in the Americas - Part 1


Ecuador: Santiago Paredes Saenz
PhD Student at the University of Oxford (UK)

“I had many influences growing up. My grandfather was an electrical engineer and my grandmother would take me on excursions to explore nature, so this made me really curious about science.”

Although it was an emerging field in his home country, the inspiration from his family lead Santiago to pursue a Bachelor’s degree in physics in Ecuador.

“I had a lot of support from my professor, Edgar Carrera. He was instrumental in initiating Ecuador’s cooperation with CERN, and so was a big influence on my decision to study particle physics.”

Upon graduating, Santiago began his PhD at the University of Oxford and now spends half of his time based at CERN. “It’s really great to be where all the science is happening. I had worked with the data from far away, but here you can just walk to an office and speak to the person who developed software for the whole experiment, and the next office is the theorist that produced the theory.”

He is currently analysing data for the ATLAS experiment, searching for collision events which may create two Higgs bosons, to gain insight into the current gaps in our knowledge. 

“People had doubts about my degree choice in Ecuador and didn’t think I could get a job when I graduated, but I am glad I chose physics. It has taken me to places and allowed me to study fields that I never would have dreamt of.”

Santiago’s advice to aspiring physicists: “Be patient. Things go wrong, and problems will seem unsolvable for a really long time but I think one of the qualities of a great physicist is patience and the ability to deal with frustration!”


Colombia: Marta Losada
President of Antonio Nariño University (Colombia)

Marta has played an important role in the development of particle physics in Colombia, helping to establish the country’s participation in the ATLAS experiment. Growing up, she didn’t have to look far for a role model in the sciences, as her mother was a mathematician.

“She’s a very driven and strong woman, who encouraged these traits in all of her children. I am hoping to foster these same characteristics in my own children, who are very open minded and interested in the work I am doing.”

During her Bachelor’s degree, no one was teaching particle physics at her institution. “Myself and a group of other students started to teach ourselves from books and journals. I also had a female professor who was extremely inspiring, and she decided to learn with us. In the end, my thesis on solar neutrinos was the first Master’s thesis in particle physics at the National University of Colombia.”

After her PhD in the US, Marta gained a fellowship position at CERN and found she was one of very few Colombians working in the field while the Large Electron-Positron collider (LEP) was running. She has since created many more opportunities for Colombians in particle physics, developing an ATLAS research team from scratch at UAN.

“I started this new research group after I had returned to Colombia and heard about the LHC. I knew Colombia had to be a part of this; there was no way we could miss out on something so important to this field.”  The UAN group has worked on the trigger system for ATLAS since 2007, using a combination of hardware and software to detect significant particle collision events in the detector.

Marta’s advice: “I think people need to be more aware of what it requires to be a physicist – they are going to have to work hard. This is true for almost anything that you want to succeed in, but you must also find ways of really loving it and making it your passion.”


Mexico: Arely Cortes Gonzalez
CERN Fellow

Arely did not initially gravitate toward science when she was growing up in Mexico, but her love of mathematics eventually led her to study physics and engineering.

Moving to the border city of Tijuana when she was 6 years old, Arely had early experience with culturally diverse environments which she would later encounter at CERN. Her interest in particle physics began after a talk at her university which described the use of particle detectors to discover hidden chambers in Egyptian pyramids. 

“I found that experiment fascinating because it was a direct application of particle physics. I sometimes have a hard time explaining the practical uses of our research and this was something so visual and tangible.”

As an undergraduate student in Mexico, she spent a summer working on the ALICE experiment. “It was a great introduction to our field’s unique working environment. They don’t just drop you in instantly into the whole group; you start out small, but still have the impression that your work has an impact.”

Following a PhD on ATLAS in the US and a postdoc position in Spain, Arely moved to Geneva in 2008, and is now a CERN Fellow continuing to work with ATLAS. She is currently coordinating the calibration of the ATLAS tile calorimeter, measuring the overall response of the detector and how it changes over time. She is often also involved in the more hands-on detector operations.

Arely’s advice: “Even though the support in Mexico is a more recent development, remember that its physicists are working at the same level as other groups. Don’t feel discouraged; your contributions will be useful to scientific projects.”


USA: Peter Onyisi
Professor at the University of Texas, Austin (USA)

Peter’s interest in particle physics began at childhood, during which he spent time travelling between the US and Nigeria.

“Most of my excitement came from the books in my local library in Nigeria. When I would go to the US for summer vacation, I would bring them along. One of my favourites was ‘The Hunting of the Quark’ which was about the first evidence that there are things inside protons and neutrons. Even if you can’t make one on its own, they are still there — they are real.”

Peter went on to study in Chicago for his Bachelor’s degree, but didn’t consider particle physics as a career until he began working with his undergraduate advisor, Henry Frisch, on the CDF experiment. Peter later completed his PhD at Cornell University working with the CLEO detector. This furthered his understanding of the field and gave him the experience to apply for a position at the ATLAS experiment. 

Now he is a professor at the University of Texas, Austin, and mainly works on Higgs boson measurements. He is also the deputy ATLAS data-preparation coordinator, turning raw signals from the detector into data for all collaboration members to analyse. 

Peter’s scientific nature extends to other aspects of his life. “Central Texas in the spring is remarkable. One of the things that struck me when I was living there was how beautiful the flowers are, so when I bought a house I began to experiment in growing different wildflower species… in an alternate universe I might have become a park ranger.”

Peter’s advice: “You need to have good ideas, but that’s not enough. You need to be willing to put in the work and to work with other people to get things done. Sometimes being more approximate but being able to complete something wins out over being perfect.”


Honduras: Jocsan Hernández Barahona
Master’s student at Kyushu University (Japan)

Jocsan discovered that particle physics can take you anywhere in the world when he moved from Honduras to Japan to study at Kyushu University. 

“It’s very different here, so adapting was a bit difficult. There was a culture shock when I arrived and I still get home sick sometimes, but one of the main reasons I came to Japan was to become culturally enriched, so it’s definitely worth it.”

He is now working on improving the weight and efficiency of silicon pixel detectors in the ATLAS tracker system and next year he will be visiting the experiment for the first time. 

However, before his undergraduate degree at the National Autonomous University of Honduras, Jocsan had found it difficult to find information on where to study physics in his home country. 

“I don’t think many people know that you can study physics in Honduras – I didn’t actually know either until I did some research around it. Now there is a Facebook page about physics in Honduras where I often describe the work I am doing and give words of encouragement for people over there. I hope I can show people that studying physics is a good choice.”

Jocsan’s advice: “You should go for it if you are truly interested in physics. It’s some of the most important ideas that humankind has ever developed and even if you come from a small country like Honduras, you can make some accomplishments if you try hard enough.”


Uruguay: Camila Pazos
Research Technician with Brandeis University, Boston (USA)

Tinkering with machines is in Camila’s nature. As the most technical member of her family, she is often relied on to fix things around the house – something she also experiences in her work at ATLAS. 

“My team is putting together the new alignment system for the upgrade of ATLAS’ innermost forward muon detector — the small wheel. We are assembling the actual detectors that go onto the small wheel, and also have to test and analyse the parts which have been shipped from our university, which involves a lot of coding.”

Camila gained experience in working with hardware during her Bachelor’s degree at Brandeis University (Boston, USA). Upon graduating, she was informed that there was an opportunity to come to CERN and continue the work she had been doing. She seized the chance and has been working on ATLAS ever since.

“We moved to the US from Uruguay when I was around 10, as my parents wanted us to have more options. My mother was really supportive of my interest in physics. She had also liked the sciences as a teenager, but she couldn’t finish high school. It’s difficult in Uruguay because you sometimes have to just stop studying and start working. She always wanted her kids to study, so when I wanted to pursue physics she thought that was great!”

Camila’s advice: “Don’t be afraid to try something new, be ready to travel and look for opportunities wherever you can! Explore your options and remember that, in physics, you must be willing to work hard.”


Peru: Franco Delgado Dador
Summer Student with Pontifical Catholic University of Peru

It was Franco’s innate curiosity that initially drew him to study physics. With only eight people in his university physics class, this proved to be an unusual choice in Peru.

“If I were ever to study something else, I would find myself asking the more basic questions like ‘where does this actually come from?’ so it would always come back to physics. I also think it’s because of my parents: my dad is good at math and critical thinking, and my mother is more creative. So, I guess the combination is a physicist!”

Franco is a summer student at CERN working with the ATLAS calorimeters, comparing simulated and real data to evaluate how well the components are functioning. “I was doing similar hardware work in Peru, but here the experiment is so huge and the data sample I’m using is much bigger.”

Though he has only been at CERN a short time, he has become immersed in the culture and aims to continue with particle physics as a career. “I never knew I would go into particle physics, but now I am here – it’s crazy. I have met so many people from all over the world. I even met someone from Venezuela who also dances salsa, so we decided to start teaching lessons to the other summer students.” 

Franco’s advice: “Of course study hard, but don’t just stay with what you are taught in school – go beyond that. Satisfy your inner curiosity! It’s really important.”