Simon Eidelman, a leading researcher at the Budker Institute of Nuclear Physics in Novosibirsk, Russia, and a professor of Novosibirsk State University (NSU), passed away on 28 June.
He was a key member of experimental collaborations at Novosibirsk, CERN and KEK, and a leading author in the Particle Data Group. Eidelman served the high-energy physics community in a variety of ways, including as Novosibirsk’s correspondent for this magazine for more than 20 years.
Simon (Semyon) Eidelman was born in Odessa in 1948. He went to Novosibirsk aged 15 to participate in a national mathematics Olympiad, and ended up staying to attend a special high school for extraordinarily gifted students. He then studied physics at NSU. Even before graduating, in 1968 Simon joined the Budker Institute and remained there his entire professional life. In parallel, he was a faculty member at NSU and held the high-energy physics chair for 10 years. Simon always cared for, helped and supported students and young colleagues.
Eidelman’s scientific activity mostly concerned experiments at e+e– colliders, beginning with participation in the discovery of multi-hadron events at the pioneering VEPP-2 collider.
In 1974 he moved to experiments with the OLYA detector at the upgraded VEPP-2M, where a comprehensive study of e+e– annihilation into hadrons was performed up to an energy of 1.4 GeV. Later, this detector was moved to the VEPP-4 collider, where high-precision measurements of the J/ψ and ψʹ masses were performed. Simon’s work at VEPP-2 and VEPP-4, and the analysis of the so-called box anomaly, made him one of the world’s leading experts on vector mesons. Together with Lery Kurdadze and Arkady Vainshtein, he also performed the first comparison of QCD sum rules with experiment.
Simon became one of the pioneers in the evaluation of the hadronic contribution to the anomalous magnetic moment of the muon
Simon was a key member of several major experimental collaborations: KEDR, CMD-2 and CMD-3 at Novosibirsk, LHCb at CERN and Belle, Belle II and g-2/EDM at J-PARC. Recently he contributed to the KLF proposal at JLab to build a secondary beam of neutral kaons to be used with the GlueX setup for strange-hadron spectroscopy. Just last year he proposed to measure the charged kaon mass with unprecedented precision using the Siddharta X-ray experiment at DAΦNE in Frascati – which would have yielded a dramatic improvement on determinations of the masses of charmonium-like exotic mesons.
Thanks to his deep understanding of hadron-production cross sections, Simon became one of the pioneers in the evaluation of the hadronic contribution to the anomalous magnetic moment of the muon, g-2. He was a founding member of the Muon g-2 Theory Initiative and a key contributor to its first white paper, published last year, which provides the community consensus for the Standard Model prediction. He was also an authority on strongly interacting hadrons and resonances, as well as the τ lepton and two-photon physics.
Simon was a key author in the international Particle Data Group (PDG) for 30 years, leading the PDG subgroup responsible for meson resonances since 2006. In recognition of his contributions, he was chosen to be the first author of the 2004 edition of the Review of Particle Physics. He was also a great source of inspiration for the Quarkonium Working Group (QWG). Attendees of the QWG workshops will remember his lucid presentations, his great enthusiasm for research and his keen scientific insights. Moreover, he was greatly appreciated for his wisdom and calm counsel during intense discussions.
Thanks to his deep knowledge and wide scientific horizons, combined with a wonderful sense of humour and a kind and friendly nature, Simon possessed a unique ability to galvanise colleagues into joint projects within many international collaborations and meetings. He was also deeply engaged in training the next generations of physicists, most recently being the driving force behind the school on muon g-2.
Simon was also a superb scientific editor. He had a rare gift of formulating scientific problems and results clearly and concisely, providing an invaluable contribution to the very large number of papers that he authored, co-authored and refereed. Several international meetings have been dedicated to Simon’s memory, including CHARM 2021 and the 4th Plenary Workshop of the Theory Initiative.
We have lost a remarkable physicist, and a dear and kind person. All who had the privilege of knowing and working with Simon Eidelman will always remember him as an invaluable colleague.