Mark Ross-Lonergan

Mark joined the Columbia Physics Department in January 2025 as an Assistant Professor, following three years as an Oppenheimer Distinguished Fellow at Los Alamos National Laboratory. His arrival marks a return to Columbia: he previously worked here as a postdoctoral researcher in experimental neutrino physics after completing his PhD in Neutrino Phenomenology at the Institute for Particle Physics Phenomenology (IPPP) at Durham University in the UK. His background in theory and phenomenology, including his PhD work and earlier master’s studies at the University of Cambridge, continues to play a central role in his research today.

Mark Ross-Lonergan is an experimental particle physicist exploring one of the most tantalizing frontiers in modern physics: the connection between neutrinos and the hidden "dark sector." Two profound observations point beyond the Standard Model, non-zero neutrino masses, verified in the laboratory, and dark matter, which comprises over a quarter of the universe yet remains undetected in any experiment. These two pillars of new physics may be deeply connected. As the only neutral fermions in the Standard Model, neutrinos provide a natural portal to hidden sectors where dark matter, sterile neutrinos, and new fundamental forces may reside, a landscape far richer than the simple dark matter candidates of early searches.

Ross-Lonergan's research leverages modern neutrino detectors to probe this frontier. Using experiments such as MicroBooNE and SBND at Fermilab, he investigates persistent anomalies that may be our first glimpses of dark sector physics, while developing analysis techniques to search for heavy sterile neutrinos, dark photons, and other exotic signatures. He is also advancing next-generation pixelated readout Liquid Argon Time Projection Chambers (LArTPCs) to enable deeper exploration of this exciting physics in future experiments.