Subject Grouping: Praxis

Antonino Zichichi, one of the most influential figures in high-energy physics and a towering presence in Italian scientific culture, passed away in Rome on 9 February 2026, at the age of 96.

Born in Trapani, Sicily, in 1929, into an ancient family from Erice, Zichichi graduated from the University of Palermo in the early 1950s. In 1955 he joined CERN, at the dawn of its experimental programme, and in 1965 he led the experiment at the Proton Synchrotron that culminated in the discovery of the antideuteron – an antinucleus composed of an antiproton and an antineutron that provided decisive confirmation of the existence of nuclear antimatter.

A professor of physics at the University of Bologna since 1960, he led the Bologna–CERN–Frascati collaboration, which carried out the first search for the tau lepton and established the experimental method through which its discovery would later be achieved at SLAC National Accelerator Laboratory. Beyond these early milestones, his results and discoveries were numerous and fundamental, including significant limits on free quark production in strong and weak interactions, the discovery of the effective energy in QCD and evidence for the first beauty baryon.

A master of invention

Equally important were his early inventions, among them the electronic circuit for time-of-flight measurements, the preshower for calorimetry and a new technology for high-precision polynomial magnetic fields. Later, by securing Italian funding for the LAA project at CERN, he launched an extensive R&D programme on innovative detection technologies. This notably allowed the development of microelectronics, which together with the design of silicon strip and pixel detectors, would become crucial for the LHC experiments and the development of the Multigap Resistive Plate Chamber (MRPC), a detector with record time resolution. The first large-scale implementation of MRPC technology was the ALICE experiment’s Time-of-Flight (TOF) system that Zichichi led for over two decades.

His scientific legacy cannot be separated from his profound and lasting contribution to the Italian National Institute for Nuclear Physics (INFN). Serving as its president from 1977 to 1982, he played a decisive role in strengthening the institute at a crucial stage of its development, consolidating its international standing and reinforcing Italy’s participation in the great global enterprises of particle physics. Under his leadership, INFN expanded its experimental commitments at CERN and in the US, while investing strategically in detector development and advanced technologies.

Zichichi was instrumental in establishing major research facilities and many large projects are tied to his name: from the LEP and LHC projects at CERN to the HERA project at DESY, and the Gran Sasso National Laboratories at INFN, that he conceived and strategically designed with its experimental halls pointing towards CERN. Today recognised as the world’s foremost underground laboratories for astroparticle physics, attracting thousands of scientists from leading institutions across the globe, the Gran Sasso National Laboratories stand as a monumental testament to Zichichi’s foresight. The idea that an international research centre such as the Gran Sasso Laboratories can serve as a crossroads for scientists from different backgrounds, cultures and institutions, collaborating in fundamental research, reflects the vision that Zichichi consistently pursued. A vision that sees science as a means of diplomacy, enabling dialogue among nations around a common goal.

Strongly convinced that scientific cooperation could be a concrete tool for diplomacy and peacebuilding, Zichichi founded the Ettore Majorana Foundation and Center for Scientific Culture in Erice, Sicily, in 1963, which became a hub for international scientific collaboration and a forum for discussion among researchers from around the world. From there, in 1982, he promoted the Erice Statement for Peace, an urgent appeal to the international scientific community to place its work in the service of peace rather than war, at a time of heightened risk of global nuclear conflict.

That same conviction informed his engagement in European and international scientific governance. Zichichi was among the founders of the European Physical Society (where he served as its president from 1978 to 1980), chaired the NATO Committee on Disarmament Technologies and represented the European Economic Community on the scientific committee of the International Science and Technology Center in Moscow. From 1986 onwards, as president of the World Lab and the World Federation of Scientists, he supported scientific development in emerging countries and focused attention on planetary emergencies.

He did not limit himself to building bridges between scientists, but also between science, culture and society. A highly skilled communicator and educator, he published widely read books and essays aimed at the broader public, and appeared frequently in the Italian media, inspiring young people across Italy and conveying to them his passion for, and belief in, the importance of scientific research. He helped shape scientific culture in Italy in the latter half of the 20th century, insisting that fundamental research is not merely a technical endeavour but a cornerstone of human progress.

Multiple honours

Over the course of his long career, Zichichi received more than 60 awards and honours in Italy and abroad, including the Knight Grand Cross of the Order of Merit of the Italian Republic and the Enrico Fermi Prize of the Italian Physical Society. He was also president of the Enrico Fermi Historical Museum and Research Centre, further testifying to his dedication to preserving and promoting Italy’s scientific heritage.

With his death, the global scientific community loses a visionary researcher, a formidable architect of international scientific collaborations, and a tireless advocate for science as a vehicle of dialogue and peace. What always struck those who shared with him the demanding and inspiring journey of research was his unfailing enthusiasm and deep passion for science, which he cultivated tirelessly until his final days. That same passion lives on not only in his discoveries and in the institutions he helped to create, but also in the generations of scientists who continue to build bridges across borders in the name of knowledge.

Erich Lohrmann, an experimental physicist who shaped the research programme at DESY, passed away on 10 January 2026 at the age of 94.

Lohrmann was born on 25 May 1931 in Esslingen am Neckar near Stuttgart. From 1950 to 1955 he studied at the Technische Hochschule Stuttgart (TH Stuttgart), where in his doctoral dissertation, completed in 1956, he investigated particle production by cosmic rays in nuclear emulsions and together with Martin Teucher observed the creation and annihilation of an antiproton shortly after its discovery at Berkeley. For this discovery, Owen Chamberlain and Emilio Segrè were awarded the Nobel Prize in Physics in 1959. From 1956 to 1961, Lohrmann continued his work on cosmic rays at TH Stuttgart and at the universities of Bern, Frankfurt and Chicago. In Chicago he also met Masatoshi Koshiba, with whom he shared a lifelong friendship.

Lohrmann joined DESY in 1961. He convinced the director, then Willibald Jentschke, that a liquid-hydrogen bubble chamber exposed to the photon beam from the 6 GeV electron synchrotron would be ideally suited to investigate hadronic reactions. Five million bubble-chamber photographs were analysed by a large collaboration, resulting in a rich scientific harvest that received great international recognition. To facilitate the measurement and analysis of millions of photographs, Erich worked on automated measurement methods and data analysis, and founded DESY’s IT group. In 1969, together with Peter Stähelin, he established the Institute of Informatics at Hamburg University, where he and members of the DESY IT group gave lectures on informatics and data analysis.

As research director from 1968 to 1972 and from 1979 to 1981, he played a key role in strategic decisions at DESY. He was one of the few scientists who encouraged Jentschke to build the electron–positron storage ring DORIS. In the years from 1966 to 1968, it was a risky decision to base DESY’s future on this technique, since the prevailing opinion among particle physicists was that it would only allow tests of the validity of QED. The discovery of the “new particles” in the November Revolution of 1974 (CERN Courier November/December 2024 p41) showed that this was the right decision, and it has shaped research at DESY until today.

Lohrmann was the driving force behind the conception and realisation of the PLUTO detector at the DORIS storage ring. Against considerable opposition, he insisted on a superconducting coil, which laid the foundation for DESY’s expertise in superconducting technology. This was subsequently a crucial prerequisite for the construction of HERA. The experimental programme at DORIS, in which Koshiba’s group was also heavily involved, proved to be extremely successful. The strong Japanese–German collaboration was continued at the large electron–positron storage ring PETRA and later at HERA. The PETRA experiments produced a wealth of new results, the most important of which was the discovery of gluons. After his term as research director ended, Erich then played an influential role in the TASSO experiment.

In the HERA project, he strongly supported Björn Wiik’s forward-looking proposal to build an electron–proton collider with a superconducting proton storage ring 6 km in circumference. In the ZEUS experiment, Lohrmann played a central role in setting up the collaboration, designing the interaction region and in data analysis, to name just a few examples. His important contributions to the critical analysis of publications continued until very recently.

Erich also promoted research with synchrotron radiation through the conversion of DORIS into a high-brilliance radiation source. Later, PETRA was also converted into a synchrotron radiation source. Today, DESY is a world leader in photon science.

From 1976 to 1978, Lohrmann served as CERN director responsible for research. Until his retirement in 1996, he was a professor at the University of Hamburg. With his lectures on physics, statistics and methods of data analysis, he inspired numerous students and provided them with a solid education. Based on his teaching experience, he also authored three books, one of them, Statistical and Numerical Methods of Data Analysis, with his colleague Volker Blobel. Together with Paul Söding, he described the history of DESY in detail up to 2008 in the book Von schnellen Teilchen und hellem Licht. Even after his retirement, Lohrmann was frequently at DESY and remained active in research. One example is the GRAVI experiment, which investigates Newton’s law of gravitation in weak fields.

Despite his great scientific achievements, Erich remained modest. Thanks to his sober yet humorous Swabian manner, his expertise and his commitment to scientists, he enjoyed great trust and esteem.

With the passing of Erich Lohrmann, physics loses a scientist of great foresight and an inspiring teacher. His contributions to physics and his scientific legacy will continue to inspire us in the future.

Matts Roos, who promoted the international standardisation of high-energy-physics data and developed the popular statistical minimisation system, passed away on 25 November 2025 in his hometown of Helsinki at the age of 94.

Roos was born on 28 October 1931. He completed an MSc degree in technical physics at the Helsinki University of Technology in 1956 and began his career in Stockholm at AB Atomenergi, where he investigated materials for radiation safety. However, he had basic science in his genes, or at least on his mind. Encouraged by his uncle, Ragnar Granit, who in 1967 was awarded the Nobel Prize in Physiology or Medicine, Roos became a research assistant in theoretical physics at the University of Stockholm, from where, a few years later, he continued to the Nordic Institute for Theoretical Physics and the Niels Bohr Institute in Copenhagen. In 1967, he defended his doctoral thesis on CP non-invariance in neutral-kaon decays.

Together with Arthur H Rosenfeld from Berkeley, Roos laid the foundations of the Particle Data Group (PDG). Rosenfeld published the first tables of particle data in 1957 and in 1963 Roos published his own particle tables. In 1964 these two tables were merged into what is now known as the Review of Particle Physics. Sixty years later, this highly cited opus has swollen to 1400 pages.

A particularly significant phase in Roos’ career were the five years he spent at CERN in Geneva, although Finland was not yet a member of CERN in 1965. Victor Weisskopf, the Director-General of CERN, invited Roos, on the basis of his work with the PDG, to apply for a temporary position in the Theory Division, then lead by Léon Van Hove. Motivated by the work on the validation of properties of by then discovered elementary particles, CERN then invited Roos to lecture on statistical methods. This course eventually crystallised into Statistical Methods in Experimental Physics, published in 1971 in collaboration with Fred James, Daniel Drijard, Bernard Sadoulet and William Eadie.

Roos’ international reputation is also based on another CERN-period achievement that greatly benefited the scientific community: the MINUIT software developed together with James. This is a versatile statistical tool that has been used in particle-physics research throughout the decades, with reference to the original publication still increasing today.

The years abroad brought the sociable and multilingual Roos a wide circle of friends and acquaintances among researchers and made him cosmopolitan. Roos returned to Finland in 1971 after the University of Helsinki appointed him as an associate professor in the field of elementary particle physics. From 1977 until his retirement, he served as a personal professor of particle physics. Later, Roos turned to cosmology in addition to elementary particles. He devoted himself to the field by writing a textbook, Introduction to Cosmology, which went through four editions between 1994 and 2015. Roos also served as a member of the International Neutrino Commission for decades. In 1996 he organised the 17th International Conference on Neutrino Physics and Astrophysics in Helsinki.

In his spare time, Roos began to pursue visual arts in the 1980s, developing over the years from an enthusiastic amateur to a professional painter. He stated that art provides a counterbalance to research work, because “science progresses logically and art illogically”. His interest in art must have been rooted in the family, as his father and brother were well-known photographers and filmmakers, and his sister was an architect.

Roos took an active part in the debates in society, supported colleagues behind the iron curtain with forbidden scientific litera­-ture or Solzhenitsyn, and established a think tank on the civil use of nuclear power. He also helped introduce Transcendental Meditation into Finland, after having experienced it himself during a congress in California in the early 1960s.

After returning to Finland, Matts Roos settled in Helsinki with his Swiss-born wife Jacqueline, whom he met while participating in a choral music society, and with the family’s three children. In the summers, the family enjoyed their cottage in the Sipoo archipelago, where many colleagues also were invited.

We shall keep the memory of the Dear alive.

Chen-Ning Yang, a towering figure in science whose numerous insights shaped contemporary theoretical physics, passed away in Beijing on 18 October 2025 at the age of 103. Yang was one of the greatest physicists of the 20th century, whose profound contributions, often based on principles of symmetry, are central to our contemporary understanding of nature.

Yang was born in 1922 in China’s Anhui province, moving as a child to Tsinghua University in Beijing, when his father was appointed professor of mathematics. Displaced by war, in 1938 he enrolled at the National Southwest Associated University in Kunming, where he earned his Master of Science in 1944, not fully removed from ongoing hostilities in the Second Sino–Japanese War. Yang wrote that his taste in physics was already formed from his education in Kunming.

He was awarded a fellowship for further graduate study in the US and enrolled in 1945 at the University of Chicago. He studied with Enrico Fermi and wrote his thesis on applications of group theory to nuclear physics in 1948 with Edward Teller as his advisor. In 1949, Yang joined the Institute for Advanced Study in Princeton, New Jersey, where he emerged as one of the world’s leading scientists. He wrote that he would probably have taken Fermi’s advice and returned to Chicago, but remained in Princeton to be nearer to Chih Li Tu, whom he married in 1951.

Landmark papers

His years in Princeton were extraordinarily productive, with many landmark papers in particle physics, including a famous analysis of particle decays into two photons, and statistical mechanics, including the celebrated Ising model Lee–Yang circle theorem. Most significantly of all, Yang developed non-abelian gauge theories with Robert Mills in 1954. These have the property that once the gauge groups are identified, new gauge particles and their interactions are determined. Over the subsequent 30 years, a combination of theoretical advances and experimental discoveries identified the gauge particles of our world, establishing Yang–Mills theories as a cornerstone of modern physics, alongside Maxwell’s equations and Einstein’s theory of general relativity. A spontaneously broken Yang–Mills theory, incorporating the Higgs boson, and combined with a Maxwell field, describes the electromagnetic and weak interactions, while a fully unbroken theory, quantum chromodynamics, describes the strong interactions. None of this could have been foreseen in 1954, but as Yang later wrote, “we thought it was beautiful and should be published”.

Yang’s collaboration with Tsung-Dao Lee in 1956 on the groundbreaking possibility of parity non-conservation in weak interactions earned them the 1957 Nobel Prize in Physics, making them the first Nobel laureates of Chinese origin. The confirmation of non-conservation in the experiments of Chien-Shiung Wu and other groups led to further work, with Lee and Rudolf Oehme, on the possibility of charge conjugation and time reversal non-invariance, which were subsequently observed and are now recognised as relevant to the predominance of matter over antimatter in the universe. Around the time of the Nobel Prize, Yang, now famous, reunited with his father from China at CERN. This was their first time together since he left for his doctoral studies in Chicago.

In 1966, Yang accepted the position of Albert Einstein Professor at the new State University of New York at Stony Brook, to which he relocated with his family. In the same year, the Institute for Theoretical Physics, now the C.N. Yang Institute for Theoretical Physics, was founded, and he led it until his retirement from Stony Brook in 1999. At Stony Brook, he continued work in particle physics, and broke new ground in the quantum structure of integrable models and the geometry of gauge field theories. He also profoundly shaped statistical physics, in 1967, discovering the pivotal relation for one-dimensional quantum many-body problems, the Yang–Baxter equation, which opened new directions for research in statistical physics, integrable models, quantum groups and related fields of physics and mathematics.

Building bridges

In 1971, his visit to China sparked a wave of visits there by other well-known scholars, earning him recognition as a pioneer in building bridges of academic exchange between China and the US. As a prominent public figure, he went on to support the restoration and strengthening of basic scientific research in China. He also helped inspire a renaissance of fruitful interplay between physics and mathematics, through his work on the geometry of gauge fields, relating gauge theories to the mathematical concept of fibre bundles, a realisation that grew out of conversations in the 1970s with the mathematician James Simons.

Starting in 1997, he served as honorary director of the newly established Center for Advanced Study at Tsinghua University, now the Institute for Advanced Study, and became a professor at Tsinghua University in 1999. In 2003, he returned as a widower to his childhood home, the campus of Tsinghua University, also spending time at the Chinese University in Hong Kong. In his words, his “life can be said to form a circle”, including a second marriage, with Fan Weng. He took on developing the Institute for Advanced Study as his new mission. Yang poured immense effort into advancing fundamental disciplines and cultivating talents at Tsinghua, making contributions that greatly impacted the reform and development of Chinese higher education.

Yang was elected member or foreign member of more than 10 national and regional academies of sciences, received honorary doctorates from more than 20 prestigious universities worldwide, and was honoured with numerous awards.

In his collected papers, Yang wrote that “taste and style are so important in scientific research, as they are in literature, art and music.” With his own taste having served as his guide, Chen-Ning Yang leaves an opus of exceptional creativity and breadth, providing tools that have enabled generations of physicists to make new discoveries of their own.

George Smoot, who led the team that first measured tiny fluctuations in the cosmic microwave background (CMB) and began a revolution in cosmology, passed away in Paris on 18 September 2025.

George earned his undergraduate and doctoral degrees at the Massachusetts Institute of Technology (MIT), and then moved to Berkeley, where he held positions at Lawrence Berkeley National Laboratory (Berkeley Lab) and the Space Sciences Laboratory at the University of California, Berkeley (UC Berkeley). Though trained as a particle physicist, he switched to cosmology and developed research projects, including using differential microwave radiometers (DMRs) on U-2 spy planes to detect the dipole anisotropy of the CMB, a consequence of the motion of the Earth relative to the universe as a whole. He then devoted himself to the measurement of the CMB in detail, and this undertaking occupied him from his proposal of a satellite experiment using DMRs in 1974 to the results of the Cosmic Background Explorer (COBE) satellite in 1992. George subsequently continued research and teaching as a member of the faculty of the UC Berkeley physics department.

In 2006, the Nobel Prize committee recognised John Mather for leading a team that determined the CMB spectrum was a blackbody (arising from thermal equilibrium) to exquisite precision, and George for leading a team that detected temperature variations across the sky in the CMB at the level of one part in a hundred thousand. Those variations were signatures of the primordial density fluctuations that gave rise to galaxies, and so eventually to us. They have been called the DNA of cosmic structure and provide a remarkable window on the early universe and high-energy physics beyond our particle accelerators. The excitement caused by the COBE CMB results was dramatically expressed by Stephen Hawking, who declared them to be “the discovery of the century, if not all time.”

After the Nobel Prize, George intensified his efforts in science education and training young scientists. Indeed, on the day of the prize, George continued to teach his undergraduate introductory physics class.

George created new research institutes internationally to support young scientists. He used his prize money to found the Berkeley Center for Cosmological Physics, a joint effort between UC Berkeley and Berkeley Lab. He also started an annual Berkeley Lab summer workshop for high-school students and teachers, now in its 19th year. Later, he founded the Instituto Avanzado de Cosmología and the international Essential Cosmology for the Next Generation winter schools in Mexico, the Paris Centre for Cosmological Physics, the Institute for the Early Universe in South Korea at the world’s largest women’s university, and more. Many of the scientists trained at those institutes went on to become faculty in their home countries and internationally, and formed their own research groups.

His open online course “Gravity! From the Big Bang to Black Holes” taught nearly 100,000 students

George took special pride in the Oersted Medal awarded to him by the American Association of Physics Teachers in 2009 for “outstanding, widespread, and lasting impact” on the teaching of physics. His massive open online course “Gravity! From the Big Bang to Black Holes” with Pierre Binétruy taught nearly 100,000 students.

In his later years, George’s scientific interests spanned not only the CMB (in particular the Planck satellite), but new sensor technologies such as kinetic inductance detectors and ultrafast detectors that could open up new windows on astrophysical phenomena, gravitational waves and gravitational lensing, features in the inflationary primordial fluctuation spectrum, and dark-matter properties.

The primordial density fluctuations for which George was awarded the Nobel Prize lie at the heart of almost every aspect of cosmology. The revolution started by the COBE results led to the convergence of cosmology and particle physics, exemplified by the centrality of dark matter as a primary issue for both disciplines. George will be remembered for this, for the many students whose lives he touched and whose research he inspired, and for his advocacy of international science.

Rohini Madhusudan Godbole, one of India’s most influential particle physicists, passed away in her hometown of Pune on 25 October 2024.

Rohini was born on 12 November 1952 to Madhusudan and Malati Godbole. Theirs was a cultured and highly educated family, and she grew up in an atmosphere of intellectual freedom and progressive ideas. Educated at the best schools and colleges in Pune, she joined the Indian Institute of Technology at Bombay, from which she graduated in 1972. She then moved to Stony Brook, where she completed her PhD in particle physics with Jack Smith in 1979. Returning to India, she worked temporarily at the Tata Institute of Fundamental Research before joining the faculty at the University of Bombay (now Mumbai). There she remained until 1997, when she moved to the Centre for High Energy Physics at the Indian Institute of Science at Bangalore (now Bengaluru). She worked there for the rest of her life, continuing after her formal retirement as an emeritus professor. It was only a few months before the end that she moved back to her hometown, to be with her family in her last days.

Rohini was a prolific researcher. She will probably be best remembered pioneering the development, with Manuel Drees, of photon structure functions for use with photon beams at future colliders, but her contributions spanned vacuum polarisation, Higgs physics, top-quark physics with polarised beams, and beyond the Standard Model physics, especially low-energy supersymmetry. She authored a well-known textbook on the latter subject with Probir Roy and Drees.

Rohini was indefatigable in promoting the cause of women in science

Rohini’s broad understanding and warm character combined to make her the best-known face of elementary particle physics from India. She worked tirelessly to promote high-energy physics inside India, organising schools and workshops, and often represented the country in international forums, such as to monitor India’s participation in the LHC and other large international collaborative experiments. Rohini was a dedicated teacher and mentor to a long series of graduate students and postdocs, and a universal elder sister or aunt for the entire community of younger particle physicists in India.

No description of Rohini can be complete without mentioning her indefatigable efforts to promote the cause of women in science. Having herself faced gender discrimination in her younger days, she was determined to ensure that young women scientists received proper opportunities and recognition. She authored two books highlighting the work of Indian women scientists, thereby setting up role models to inspire the younger generation. Even more than these books, however, her own presence and encouragement left a mark on two generations of particle physicists, in India and abroad.

Rohini’s signal contributions were recognised by many awards and distinctions. The government of India awarded her the coveted Padma Shri in 2019, and the government of France awarded her the Ordre National du Mérite in 2021, mentioning her important role in furthering scientific collaboration between India and France. But her true memorial lies in the unique place she holds in the hearts of thousands of students, collaborators, friends and acquaintances. She was an extraordinary person who carved out a niche all by herself, with her scientific talents, her indefatigable energy, her universal amiability and her indomitable will. Her loss is sorely felt.