The end of the year 2025 marked the end of an era, which had already started the year before with the departure of Josh Bendavid (now a permanent CERN staff). Zhangqier Wang and Kenneth Long left the PPC and are now defining their own path. While this Farewell comes a little late I would like to take the time and highlight their essential contributions during the era of the first W mass measurement and our first deep dive into flavor physics at CMS.
Zhangqier Wang – Qier – joined the group on January 1, 2020, highly recommended from UC Davis fresh after his PhD. At MIT he jumped right into the construction of the SubMIT analysis facility for the Physics department, the Production and Re-processing task in the CMS Computing Operations and was a force in the analysis.
He dove deep into the Dark Photon search with low masses [JHEP 12, 070 (2023)] using the novel scouting data. At the same time he picked up the “Mono-Jet” Run 2 legacy analysis [JHEP 11, 153 (2021)] together with our friends at Boston University. With this not being enough he joined Dima and became a lead author on the B to dimuon rare decay analysis [Phys. Lett. B 842, 137955 (2023)]. Finally he performed one of the first Run 3 analyses looking for D mesons decaying to dimuons [PRL 135, 151803 (2025)] For this analysis he used the D* trick which makes the analysis substantially different from just looking at the two muons.
Qier has just started as an assistant professor at Zhejiang University in China. All the best!
Kenneth Long joined the group on November 1, 2021 finishing a long stint as a CERN fellow working intensively on the analysis which has been often referred to as the ‘kiss-of-death’ for any postdoc or graduate student. It is truly a very, very hard analysis and needs so much effort that it was not possible to be completed within the duration of a postdoc position and even for graduate students it was a far stretch. Kenneth agreed to continue with the W boson mass analysis [arXiv:2412.13872] and put MIT on the map for this important analysis. Kenneth was the master of the theory uncertainty a very complex topic that required ingenuity and excellent communication skills to extract the best systematic uncertainty treatments from our theory colleagues.
Kenneth also jumped into the responsibility on the Storage Manager and File Transfer system where he carried MIT and CMS through an exciting stretch of data taking.
Kenneth has moved on to a permanent staff researcher position at CNRS, Lyon. He seems to be spending most of his time at CERN, though.