Peter Jenni participated in
CERN experiments at the
Synchro-Cyclotron (1972/3), at the Proton Synchrotron (1974/6), and as ETHZ Research Associate at the
Intersecting Storage Rings (ISR) (1976/7), the first high-energy hadron collider. From 1974 to summer 1976 he worked as a
CERN Fellow in the group of M. Ferro-Luzzi. The group measured the
Coulomb nuclear interference
scattering of π±, K± and p± on hydrogen and deuterium in two experiments at the
CERN PS. The measured real parts of the forward scattering amplitudes were used in dispersion relations. One of these measurements was the subject of the doctoral thesis (H. Hofer). From 1976 to 1977 Research Associate at the Swiss Federal Institute of Technology in Zürich (
ETHZ) working in the CERN-ETH-Saclay collaboration R702 at the
CERN Intersecting Storage Rings (P. Darriulat, B. Richter). The experiment covered studies on electron pair production, on e μ events as a signature for charmed particles, and on very high transverse momentum π0 production in pp reactions. During 1978 and 1979, Research Associate at the Stanford Linear Accelerator Centre (
SLAC), Stanford, USA, in B. Richter's group. Participated in the MARK II SLAC-LBL Berkeley experiment at the e+e– storage ring
SPEAR. Mainly involved in the following physics analyses: two-photon reactions, meson form factors, and search for the charmed mesons. The first measurement of the two-photon widths of the η prime was giving further direct support to the
quark model. In SLAC he also worked on operating the liquid-argon
calorimeter for the MARK II experiment where his interest in high-performance calorimetry was developed. He became a
CERN staff member in 1980 working with the
UA2 experiment at the
Super Proton Synchrotron collider (major involvement in the discoveries of jets and the
W and Z bosons). Worked on the design for the UA2 upgrade since 1984, with special motivation for missing transverse energy signatures. Project leader of the new end cap calorimeter constructed for the upgraded UA2 experiment. As from March 1987, also group leader of the CERN UA2 group. Coordinated calorimeter and trigger work for the upgraded UA2 experiment. Already during the UA2 time, strong interest in the physics and instrumentation at future colliders, in particular LHC. Early involvement as convener of the jet study group at the ECFA-CERN LHC workshop 1984 (Lausanne, Geneva), member of the advisory panel on the physics potential and the feasibility of experiments at the multi-TeV energies (La Thuile workshop 1987), and calorimetry overview at the ECFA study week on instrumentation technology for high-luminosity hadron colliders (Barcelona 1989). He more and more shifted to the Large Hadron Collider (
LHC). From 1991 the main activities concentrated on tasks related to the informal spokespersonship first of a proto-Collaboration. Peter Jenni was involved in the early phases of the calorimeter R&D projects RD1 and RD3, during 1990–1992. In 1995, after formal approval of the ATLAS project, he was elected Spokesperson of the experiment, which today comprises some 3000 scientists representing 183 Institutions from 38 countries. He was re-elected several times and retired from this duty in February 2009, with
Fabiola Gianotti as his successor. He retained however a strong involvement in the operation and physics of the experiment. After his retirement as a CERN Senior Research Staff end of April 2013, Peter Jenni has become a Guest Scientist and Honorary Professor with the
Albert-Ludwigs-Universität Freiburg, keeping his full engagement with the ATLAS experiment. He is also an Honorary Professor at the
University of Science and Technology of China in Hefei, China. He has authored and co-authored many review articles about the LHC project, the Higgs boson discovery, and the history of hadron colliders, for example in 2021 in the
CERN Courier. In 2014 he has been elected as corresponding member of the
Bavarian Academy of Sciences, in 2019 as a Fellow of the European Academy of Sciences EurASc., and in 2023 corresponding member of the
Slovenian Academy of Sciences and Arts. == Advisory roles – Major physics committee involvement ==