NRF 25 years: Prof Deepak Kar

This year, the NRF is celebrating a major milestone in our history as we commemorate 25 years of Research, Innovation, Impact and Partnerships. It gives us great joy to share the accomplishments and impact of the many students and researchers we have supported during various stages of their careers. We thank all participants for submitting their stories and we hope that you enjoy reading about their journey with the NRF.

Professor Deepak Kar is a Professor of Physics at the University of the Witwatersrand. He is also a Royal Society Wolfson Visiting Fellow at the University of Glasgow and, as an internationally acclaimed researcher, currently holds an NRF B-rating. He has received several grants from the NRF.

How did your journey start?

Academic research is international by nature, and more so for particle physics, where thousands of researchers from all over the world work at facilities such as CERN. I have been fortunate to have my career span over four different continents. After completing my Master’s degree in India, I moved to the University of Florida in the US for my Doctoral degree. I worked on the CDF experiment at Tevatron, the world’s highest energy particle collider at the time, where I performed the most comprehensive measurement of the underlying event.

The Large Hadron Collider (LHC) at CERN started just when I finished my PhD, and I worked on ATLAS as a postdoctoral researcher first in Dresden, Germany, then in Glasgow, UK. At ATLAS, I initially took a leading role in soft-QCD measurements, and tuning Monte Carlo event generators based on the results we got, subsequently focussed with jets, including implementing the then best-performing shower deconstruction tagger.

I then moved to the University of Witwatersrand in Johannesburg as an academic, and in the last eight years have secured numerous national and international grants; an award for outstanding young faculty; and have been promoted twice.

My research focus has shifted to searching for signs of new physics, including dark matter in novel collider topologies, as even a decade after the most famous discovery of the Higgs boson at the LHC, we have no other breakthrough of that magnitude.

How has your affiliation with the NRF impacted your studies/career?

While the SA-CERN programme under the auspices of DSI/NRF generously supports our research in the ATLAS experiment, I have been fortunate enough to have been supported by the NRF with generous funding through the Competitive Support for Unrated Researchers (CSUR), Competitive Programme for Rated Researchers (CPRR), and Knowledge, Interchange and Collaboration (KIC) grants, as well as being awarded a high NRF rating.

Being from outside the country, these were invaluable to kickstart my research programme by recruiting the best postgraduate students and postdocs, and allowing me to travel to conferences and meetings overseas. These, in turn, allowed me to climb the promotion ladder at Wits; develop collaborations and secure international grants with them; and establish myself as an internationally recognised researcher. None of these probably would have happened without the NRF’s support!

What is your research focus on/what is your area of expertise?

I have been advocating for a bottom-up approach to designing searches based on uncovered topologies, rather than the top-down, mostly signature-driven approaches that have been employed so far. I have managed to publish pioneering search results using ATLAS data. They include the search for a boosted heavy neutrino, and the search for semi-visible jets, which arise if we consider a strongly interacting dark-sector (as opposed to the weakly interacting scenario searched for so far).

My focus has been to design these searches and extract the most information from the results. I have been working on these aspects closely with colleagues from across the world to explore the phenomenology of new physics models and assess how current results can exclude or constrain potential new physics models, and how to interpret current results to constrain new physics scenarios at a much higher energy scale.

Why is your work/studies important?

Fundamental science is universal. Understanding nature at its deepest level transcends national boundaries. However, being part of the largest science experiment that humanity has ever performed means I can make South African students part of this adventure, make them dream, and enhance the global reputation of the country.

Also, developments in basic sciences are incremental. We rarely achieve something ground-breaking often, but we are all small cogs in a big wheel. While I would love to find dark matter, figuring out what is not dark matter is perhaps more important, as the community narrows down the possibilities.

What are some of your proudest academic achievements?  

I have authored a textbook on experimental particle physics based on the Honours course I started at Wits, which was the first such book in the field. It was published by the Institute of Physics (UK) and has been downloaded over thousands of times.

The most recent paper on the first semi-visible jets search result has been highlighted by ATLAS collaboration in a press briefing and an outreach video, which is a rare honour.

I have secured support from CNRS (France), STINT (Sweden), and was awarded the UCL-Wits seed fund. The funding from CNRS is to organise a school for computing in High Energy Physics for African students at Wits in January 2024 with leading international researchers as lecturers.

I was awarded a Royal Society Wolfson Visiting Fellowship to spend my sabbatical year at the University of Glasgow.

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