It was with profound shock and sadness that we learned of the passing of Mark Rayner, editor of CERN Courier, on 23 March due to sudden illness. His love of physics, talent for communication and editorial rigour raised the bar for this magazine.
Mark was born in Hounslow, England, on 7 October 1983 and studied physics at Worcester College, University of Oxford, from 2002 to 2006. In 2005 he spent three months at CERN as a Summer Student working on tests of the ATLAS transition-radiation-tracker end caps. He continued at Oxford with a PhD, participating in the Muon Ionisation Cooling Experiment (MICE) based at the Rutherford Appleton Laboratory. His thesis described the development of a novel technique for characterising the MICE muon beam and demonstrating its suitability for a muon cooling measurement, an essential step on the path towards a possible neutrino factory and muon collider.
In 2011, he moved from accelerator physics to neutrino physics, joining the University of Geneva both as a lecturer and as a researcher working on the T2K, Hyper-Kamiokande and BabyMIND experiments. Over the years, Mark supervised several students. In the process he deconstructed the weaknesses in the T2K detector system, realising that an upgrade of the detector setup at the source was necessary for the long-term programme. An upgrade was proposed, with a much simplified and better geometry, largely using detector techniques developed in MICE. It was approved in 2019 and is now successfully operational.
As a physicist, Mark stood out for his care and originality. He liked simplicity and elegance, and to understand the relative causality of correlated observations. He made many important contributions and was happy to do so, without seeking recognition.
A natural educator and communicator, Mark trained as an apprentice physics teacher at Ecole Internationale de Genève in 2018. The following year, he joined CERN as a senior fellow working on the Courier, where he played a major role in the launch of the magazine’s website and rose quickly to become deputy editor. When his fellowship ended, Mark took his exceptional skills to the World Economic Forum, where he managed the production of a portfolio of publications and tools relating to education, skills and learning, and served as lead author for the Future of Jobs report 2023.
Mark returned to CERN as a staff member in 2024, as editor of the Courier. Over a short period, his eye for design, his mastery with words, and his ability to interpret and display complex information in novel ways sharpened the impact of CERN’s flagship publication. He also paid particular attention to improving the visibility of gender diversity in these pages and to developing the magazine’s online presence, enabling him to connect particle physics with new audiences. He took great pride in his work and in engaging with authors to shape their stories. He had huge respect for those who devoted their lives to fundamental research in physics and was widely recognised for his dignity and professionalism among members of the international particle-physics community.
Above all, Mark cared deeply about everything he did, and especially about the well-being of others. His pursuit of excellence and his remarkable attention to detail set a standard that inspired those around him, and this is reflected in the deeply motivated team that he built and nurtured. He was highly cultured, played the flute, and sang in the Geneva Gospel Choir.
Mark was a man of great intellect, warmth and spirit, whose presence brought light to those fortunate enough to know him. He will be remembered with great respect and will be profoundly missed.
