Hans Joachim Specht (6 June 1936 – 20 May 2024) was a German experimental particle and nuclear physicist and university professor at the Heidelberg University.

Biography Born in Unna, Specht attended the Gymnasium in Kamen and studied physics from 1956 to 1962 at LMU Munich, TU Munich, and ETH Zurich. He received his diploma in 1962 from TU Munich, followed by his doctorate summa cum laude in 1964, with Heinz Maier-Leibnitz as his mentor.Curriculum vitae of Hans Joachim Specht () His diploma and doctoral research was based on atomic physics experiments at the Forschungsreaktor Muenchen (FRM). Studying x-rays emitted in low energy heavy-ion collisions he opened the field of quasi-molecules.Specht: Ionisation innerer Elektronenschalen bei fast-adiabatischen Stössen schwerer Ionen. Zeitschrift für Physik 185, 1965, S. 301–330 (). Specht’s next scientific focus shifted to nuclear fission and the shape of the fission barrier. As a postdoc with a NRC Fellowship at the AECL Nuclear Physics Laboratories in Chalk River, Canada, he introduced novel gas-filled detectors and identified vibrational states in the second minimum of the double-humped fission barrier.Specht H.J., Fraser J.S., Milton J.C.D., Davies W.G.: A High Resolution Study of the 239Pu (d,pf) Reaction Physics and Chemistry of Fission, volume I, International Atomic Energy Agency, Vienna, 1969, 363–373 In 1969, Specht returned to Munich as an assistant at LMU Munich, where he made his habilitation in 1970 and was promoted to associate professor. Working at the joint accelerator facility of LMU Munich and TU Munich, Specht made a landmark discovery in 1972: he showed that fission isomers are strongly deformed nuclear states, providing the first experimental proof of shape isomerism in nuclei.Specht et al., Phys. Lett. 41B (1972) 43–46 (). This has been described as the most significant advancement in the nuclear shell model since introducing spin–orbit coupling. This discovery brought him international recognition and many academic offers, but he chose to continue his research in Heidelberg.

In 1973, Specht became a full professor at the Heidelberg University. He initially conducted research at the Max Planck Institute for Nuclear Physics in Heidelberg and GSI Helmholtz Centre for Heavy Ion Research in Darmstadt. By the early 1980s, his focus had shifted to the study of quark-gluon plasma formation in high-energy heavy-ion collisions at CERN.G. Agakiviev et al. CERES: Enhanced Production of Low-Mass Electron Pairs in 200GeV/u S-Au Collisions at the CERN SPS. Physical Review Letters 75, 1995, S. 1272–1275 ().R. Arnaldi et al., NA60: First Measurement of the rho Spectral Function in High Energy Nuclear Collisions. Physical Review Letters 96, 2006, 16302 () This transition to high-energy nuclear physics was encouraged by physicist William J. Willis. Specht was a member of the experiment R807/808 at the Intersecting Storage Rings (ISR), the spokesperson of a first generation ultra-relativistic heavy-ion experiment NA34-2/HELIOS, the founder and spokesperson of NA45/CERES,List of CERES Members (). and, since 2003, a member of NA60 at the Super Proton Synchrotron (SPS),Interview on CERN website (). all while building a strong heavy-ion research group at Heidelberg University. He spent sabbatical years at CERN in 1983/84, 1990/91, and 2003/2004. In 1996, he was Chairman of the International Conference on Quark Matter held in Heidelberg.Quark Matter Conference 1996 (). Specht also played a key role in shaping the ALICE experiment, contributing to the conceptual design of a heavy-ion detector at the Large Hadron Collider (LHC), and securing institutional support from Germany for the project. ECFA-Aachen conference 1990.

From 1992 to 1999, Specht was the Scientific Director of GSI in Darmstadt.GSI website (). Here he initiated the use of ion beams for tumor therapy and oversaw the first patient treatments conducted on the grounds of the laboratory itself, in collaboration with the Radiology Clinic of the University and the German Cancer Research Center in Heidelberg.Specht u.a.: Präziser Beschuß mit schweren Ionen. Ruperto Carola, 3/95 (Online). This paved the way for the clinical facility Heidelberger Ionenstrahl-Therapiezentrum (HIT) in Heidelberg, which went into operation in 2009.

Specht also worked together with Hans Guenter Dosch and others in interdisciplinary research on the physics and neurophysiology of the early processing of central musical quantities in the brain,P. Scheider et al.: Morphologie of Heschl’s Gyrus reflects enhanced activation in the auditory cortex of musicians. Nature Neuroscience 5, 2002, 688–694 ()P. Scheider et al.: Structural and functional asymmetry of lateral Heschl’s gyrus reflects pitch perception asymmetry. Nature Neuroscience 8, 2005, 1241–1247 () like tone pitch and tone spectrum. Specht had played the piano since childhood.

In 1999, Specht and Dosch were invited as Loeb Lecturers at Harvard University.Loeb Lecturer:s - Colloquium: Musical Harmony: Physics, Physiology and Psychology - Lecture I: Musical Pitch: Temporal vs. Spectral Perception - Lecture II: Physics of Musical Instruments and Pitch Perception () In the same year Specht received the Werner-Heisenberg-Medaille of the Alexander von Humboldt Foundation. In 2000, he became a member of the Heidelberg Academy of Sciences and Humanities.

In 2004, Specht became professor emeritus.

Specht died on 20 May 2024, at the age of 87.

In July 2025, an open-access book titled "Hans Joachim Specht — Scientist and Visionary" was published by Springer Nature. The book includes a foreword by Carlo Rubbia and features contributions from nearly 30 colleagues and collaborators, framing Specht’s biography (in his own words). It is available through the Springer website.

Publications Nuclear Fission. Rev. Mod. Phys. 46, 1974, p. 773–787 (Online). Spectroscopic Properties of Fission Isomers., with V. Metag et al., Phys. Reports 65, 1980, p. 1–41 (Online). Reaktionen zwischen schweren Atomkernen – gegenwärtige und künftige Entwicklungen. Physikalische Blätter, Vol. 37, 1981, no. 7, p. 199 (Online). Quark Matter: Proceedings of the Sixth International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions — Quark Matter 1987, Nordkirchen, FRG, 24–28 August 1987., edited by H. Satz, H. J. Specht, and R. Stock, Springer, 2012. ISBN 978-3-642-83524-7 (Online). Originally published as Zeitschrift für Physik C – Particles and Fields, Vol. 38 (1–2), 1988. . Gute Physik mit vorhandenen Geräten machen. Physikalische Blätter, Vol. 49, 1993, p. 46–48 (Online). NA60: In Hot Pursuit of Thermal Dileptons., with S. Damjanovic and R. Shahoyan, CERN Courier 11/2009, p. 31–34 (Online).

References

External links Homepage Article in "Heidelberger Physiker berichten - Rückblicke auf Forschung in der Physik und Astronomie, Band 3: Mikrokosmos und Makrokosmos", Heavy-ion physics and the SPS: a long way together (2016) Heidelberg University: Fest Colloquium on the occasion of Hans Joachim Specht's 80th birthday Open Access Book "Hans Joachim Specht - Scientist and Visionary" - published by Springer Nature