The 16th International Workshop on Tau Lepton Physics (TAU2021) is dedicated to Simon Eidelman and Olga Igonkina, colleagues, friends and brilliant physicists who both made major contributions to physics, and in particular to the field of tau lepton physics research.
Simon Eidelman (1948 - 2021), chief researcher of the Budker Institute of Nuclear Physics and of the faculty at the Physics Department of Novosibirsk State University is remembered and honored for his early ground breaking work on electric-positron colliders, and his later work with the CMD-2 and CMD-3 groups at Novosibirsk, Belle and Belle-2 in Japan, and LHCb at CERN. He was among the pioneers in terms of evaluating the hadronic contribution to the anomalous magnetic moment of the muon, based on measurements taken at e+e− colliders. For many years Simon was an active member of the Particle Data Group. He was a member of the International Advisory Committee of the TAU Workshop Series
Olga Igonkina (1973 - 2019) was Senior Researcher at Nikhef, and professor by extraordinary appointment at Radboud University Nijmegen. She joined the ATLAS collaboration in 2006 and was a key member, pursuing her research with enthusiasm and passion. She organized the 15th International Workshop on Tau Lepton Physics in Amsterdam in 2018. She was a dedicated scientist, teacher and mentor, and is greatly missed by colleagues, friends and all who knew her.