Enzo Bertolini 1932–2017 •  Ferdinand Hahn 1959–2018 •  Vincenzo Palmieri 1962–2018 •  Richard Taylor 1929–2018

Enzo Bertolini 1932–2017

Born in Verona, Italy, on 4 May 1932, Enzo Bertolini graduated in electrical engineering and, subsequently, in applied nuclear physics at the University of Padua in 1959. He then started his research work at CERN in the field of high-energy physics. There he worked with a talented young man named Carlo Rubbia, and the pair carried out some important work for the epoch – for example, determining the muon total capture rate in liquid hydrogen.

In 1962 Bertolini moved to Frascati (ENEA, Italy) to work on plasma physics and explore electricity generation via a magnetic-hydrodynamic generator. From 1973 to 1997 he was a member of the directorate of the EU JET project based in the UK, where eventually he became chief engineer. JET is currently the most important experiment in the world for the study of fusion energy: in 1991 it produced a small amount of fusion power (1.7 MW) for the first time on Earth, rising to 16 MW in 1997. These results have been instrumental in the design and construction of ITER, which should prove the feasibility of a thermonuclear reactor for the production of electricity.

In his many fields of expertise – particle physics, electricity generation, plasma physics, fusion, astronomy and astrophysics – Bertolini presented at international conferences and published more than 120 scientific papers. In 1969 he started his collaboration with the University of California at Davis and Santa Barbara, first as visiting professor and, from 1988, as adjunct professor, teaching in the field of energy conversion. From 1999 to 2007 he served as consultant for the government of South Korea in the field of fusion energy. He has also been on scientific and technical committees at CERN (including contributions for the design of the ATLAS experiment at LHC), the Italian Space Agency, and more recently he was an evaluator of research proposals for the EU Framework Programme. From 2006 to 2016 he was director of the Fondazione Clément Fillietroz-ONLUS (Aosta Valley, Italy), operating the Astronomical Observatory of the Autonomous Region of the Aosta Valley and the Planetarium of Lignan.

Enzo Bertolini passed away in his home in the Aosta Valley on 30 June last year. He was a true “man of science”.

• Jean Marc Christille and his colleagues at Lignan.

Ferdinand Hahn 1959–2018

It was with great sadness that we learned that Ferdi Hahn passed away on 4 March. He was an enthusiastic and highly skilled colleague, and an openhearted friend.

Ferdi first came to CERN in 1987 as technical student of the University of Wuppertal, when he joined the barrel-RICH project for the DELPHI experiment at LEP. As part of his diploma thesis, he participated in the photon detector project, SYBIL, a TPC-like drift chamber with single photoelectron detection, which was a prototype of the DELPHI barrel-RICH system.

Here, Ferdi became very much acquainted with all hardware and software aspects of such a test program, both in the innumerable technical matters and in the analysis of the data taken. From 1990, as a CERN fellow, he was heavily involved in the commissioning of the drift tubes of the RICH detector, a particularity of the DELPHI experiment, followed by the development of the temperature control of the barrel RICH. A specific part of the detector was not delivered in time, so Ferdi immediately drove 800 km to the company and back again to allow the start of data taking on time in 1989. Later, Ferdi completed his PhD with a measurement of the differential cross-sections of charged kaons and protons using the DELPHI detector, taking advantage of the unique RICH system.

In 1995 Ferdi joined the CERN physics department as a member of the DELPHI gas group. As section leader in the support groups to CERN experiments and deputy group leader of the DELPHI detector unit, he perfected the operation of the many and complex DELPHI gas systems. He also structured the LHC experiments gas working-group, which led to a professional and efficient system for all LHC detectors.

After having led the detector technology group of the physics department between 2007 and 2008, Ferdi then took over the technical coordination of the NA62 experiment with considerable commitment and great competence in many experimental aspects. Through the preparation of the Technical Design Report and the coordination of the entire installation of the experiment, his exquisite ability to bring collaborators from all kinds of cultures together was clearly an asset for the success of the project.

Knowing that the NA62 experiment was operating smoothly, Ferdi happily agreed to support the physics department as deputy head in 2015. As part of the management, he was in charge of the coordination of the technical groups in the department, including the planning of personnel. With his pleasant manner, patience and exemplary communication skills, he solved numerous tricky problems.

Ferdi was treasured as a close colleague by many; it was a pleasure to work with him. His open character and smile made it easy to discuss subjects, even when they involved complicated issues. He was enthusiastic and full of energy, always ready to help. His friendly way of dealing with people was backed up by a deep competence in technical issues. He was one of a kind and will be sadly missed.

• His friends and colleagues.

Vincenzo Palmieri 1962–2018

Vincenzo Palmieri, one of the most active members of the superconducting radio-frequency (SRF) community, passed away on 16 March. Vincenzo graduated cum laude in physics at the University of Naples Federico II in 1987, and started his career in the group of Cristoforo Benvenuti at CERN, as a technical student. Then he was hired by INFN in Legnaro to develop techniques to sputter quarter-wave cavities for the ALPI accelerator, where he founded and was responsible for the Laboratory of Superconductivity and Surface treatments.

Vincenzo was a unique character in the SRF community, always giving inspiring seminars and colouring them with unconventional pictures and videos. He had an out-of-the-ordinary energy that has pushed the entire community to look for new ideas and challenges.

He also had countless interests outside physics, from bonsai art and languages to chess, table tennis and graphology. He was always motivated to share his knowledge and train young researchers, and proposed and directed a master’s course at the University of Padua in surface treatments for industrial applications. He was convinced of the necessity for science to meet industry, making him one of the pioneers of technology transfer in the accelerator community.

Vincenzo was the inventor of several breakthrough techniques in SRF. This includes the development of seamless cavities by spinning and of various chemical treatments to reduce the cost and environmental impact while improving cavity performances.

He collaborated with numerous institutes across the world, including CERN and DESY, contributed to more than 280 publications, held three patents and was the supervisor and tutor of about 100 theses. He also drove many contract agreements between research institutes and industries.

Vincenzo leaves a large community of colleagues, students and friends with a legacy of inventions, anecdotes and an inextinguishable example of enthusiasm, integrity and love for science. Our thoughts go to his wife Emanuela and his daughters Eulalia and Ludmilla, who were always the first and constant topic of conversation with his friends.

• His friends and colleagues.

Richard Taylor 1929–2018

Richard E Taylor died at the age of 88 on 22 February at his home on the Stanford campus in the US. Taylor was the co-recipient of the 1990 Nobel Prize in Physics, along with Henry Kendall and Jerome Friedman of MIT, for their discoveries of scaling in deep-inelastic electron–proton scattering. It was these results that led to the experimental demonstration of the existence of quarks.

Taylor was born in Medicine Hat, Alberta, Canada, to Clarence and Delia Taylor. He was interested in a career as a surgeon, but an early explosion while using a chemistry set as a child cost him parts of two fingers and the thumb on his left hand – and thus pushed him towards a career in science. He was an undergraduate at the University of Alberta, receiving a bachelor and then master of science in 1952. At Alberta, he married Rita Bonneau in 1951.

Taylor then went to Stanford, working at the Stanford High Energy Physics Laboratory (HEPL). In 1958, he was invited by colleagues at École Normale Supérieure in Orsay to work on experiments for their new accelerator at the Laboratoire de l’Accelerateur Lineare. After three years, he returned to the US, spending a year at Lawrence Berkeley National Laboratory. He then returned to Stanford to complete his PhD under Robert Mosely in 1962. Wolfgang Panofsky invited him to join the core group building the Stanford Linear Accelerator Center (SLAC), roughly 1 km west of the main Stanford campus. Taylor was given responsibility for the “Beam Switchyard” at the end of the linear accelerator that analysed and steered beams to experiments and for the large “End Station A” and its electron spectrometers. Taylor organised a talented group at SLAC including David Coward and Herbert (Hobie) DeStaebler, which carried out the design and construction of these major facilities. The three electron spectrometers with momentum ranges centered around 1.6, 8 and 20 GeV/c made the critical measurements that established SLAC in the forefront of particle physics.

Taylor led his group at SLAC into a collaboration with Caltech and MIT that foresaw the rise of powerful particle-physics collaborations now at the scale of a few thousand physicists for the major LHC experiments. That collaboration proposed and carried out a series of experiments beginning with the elastic scattering of electrons off protons at high momentum transfer in 1967. The measurements extended those made by Richard Hofstadter at HEPL, but led to no surprises.

The proposal for deep-inelastic scattering had no mention of point-like particles in the nucleon. The inelastic cross sections beyond the nucleon resonances were unexpectedly large and flat with increasing momentum transfer, especially when compared to elastic scattering. The data also displayed a simplifying feature called scaling – a prediction by Bjorken from current algebra – suggesting that deep-inelastic cross sections could be expressed as a function of one kinematic variable. These results were extended by Taylor’s group and MIT into more kinematic regions and to studies of the neutron with a deuterium target.

At the “Rochester Conference” in Vienna in 1968, Panofsky summed up the first public results of the experiments with the comment: “Therefore, theoretical speculations are focused on the possibility that these data might give evidence on the behaviour of point-like, charged structures within the nucleon.” Following a visit to SLAC in August 1968, Richard Feynman introduced his “naïve parton theory” in which electrons scattered from point-like free partons give both the observed weak momentum-transfer dependence and scaling. Subsequent experiments by Taylor and collaborators allowed the two nucleon structure functions to be separated, determining that the partons were spin-½ particles. Evaluations of sum rules derived by Bjorken and Kurt Gottfried were consistent with charge assignments in the nascent quark model. Finally, the Gargamelle neutrino and antineutrino results at CERN confirmed the Gell–Mann–Zweig quark model, and these experiments collectively gave rise to the Standard Model of particle physics.

Taylor’s connections to Paris, and later DESY and CERN, continued as a theme through his life. He was awarded a doctorate (Honoris Causa) by the Université de Paris-Sud. After becoming a member of the SLAC faculty in 1968, Taylor won a Guggenheim fellowship and spent a sabbatical year at CERN. He received an Alexander von Humboldt award and spent the 1981–1982 academic year at DESY. Taylor’s group at SLAC was a lively place, with many young European visitors who became staunch colleagues and friends.

In 1978, an experiment at SLAC led by Charles Prescott and Taylor demonstrated parity violation in polarised electron–deuterium scattering – a very challenging experiment that followed negative results from atomic-physics experiments. Parity violation was the essential component of the unification of the electromagnetic and weak interactions, another key chunk of the Standard Model that led to the Nobel Prize for Sheldon Glashow, Abdus Salam and Steven Weinberg in 1979.

Taylor also was awarded the W K H Panofsky Prize, and was a fellow of the American Physical Society, American Association for the Advancement of Science, Royal Society and the Royal Society of Canada. He was also a member of the American Academy of Arts and Sciences and the Canadian Association of Physics, a foreign associate of the National Academy of Science, and Companion of the Order of Canada.

Taylor stayed rooted to his Canadian origins, often vacationing in Medicine Hat where he maintained a home and enjoyed fly fishing in the local streams. He always saw himself as an experimentalist, saying in a 2008 Nobel-prize interview: “My job was to measure things and to make sure that the measurements were right. It is the job of the theoretical community to understand why things are the way that I see them when I do experiments.”

Taylor was a large man and pretended to enjoy a reputation of being somewhat fierce. His friends and colleagues all knew him as a gentle soul, caring deeply for SLAC and always promoting the younger generations of scientists. He is survived by his wife Rita and son Ted.

• Martin Breidenbach and Charles Prescott, SLAC National Accelerator Laboratory.