Maurice Jacob 1933 - 2007

CERN theorist Maurice Jacob passed away suddenly on May 2nd, following a heart attack. Throughout his research career, Maurice was a leader in the theory of high-energy hadron physics. In his early days, he made many key contributions, together with Giancarlo Wick, to the development of the helicity formalism that is being used increasingly in modern theoretical calculations. He was an expert on diffraction physics. Together with Sam Berman, he made the crucial observation that the appearance of point-like parton structures in deep-inelastic scattering implied the existence of high-transverse-momentum processes in proton-proton collisions, as subsequently observed at the CERN ISR. He was a pioneer of the studies of inclusive hadron-production processes, including scaling and its violations. Together with Ron Horgan, he made detailed predictions for the production of jets at the CERN proton-antiproton collider, which were subsequently discovered by the UA2 and UA1 experiments.

Maurice worked closely with his experimental colleagues in predicting and interpreting results from successive CERN colliders. He organized indefatigably regular meetings on ISR physics, bringing together theorists and experimentalists to debate the meaning of new results and propose new measurements. He was one of the strongest advocates of the CERN proton-antiproton collider when it was proposed by Carlo Rubbia, and influential in preparing and advertising its physics. He organized the Les Houches workshop in 1978 that brought the LEP project to the attention of the wider European community of particle physicists. He also organized the ECFA workshop in Lausanne that made the first exploration of the possible physics of the LHC. It is a tragedy that Maurice did not live to enjoy the data from the LHC.

Between 1982 and 1988, Maurice was the leader of the CERN Theoretical Physics Division, and greatly involved in the management of the laboratory. He was always scrupulous in his responsibilities, and conscientious to a fault. Colleagues who were in the Division at the time will always remember his human understanding and his dedication to ensuring that they could progress in their research without being troubled by the administrative burden that he shouldered so unobtrusively. His cameo performances in the Theory Division Christmas Party Play were always greatly appreciated, particularly the year he appeared as a blue-faced Schtroumpf.

In parallel with his activities and responsibilities at CERN, Maurice somehow found the time and energy to play prominent roles in the French Physical Society, of which he was president in 1985, the European Physical Society, of which he was president from 1991 to 1993, and in scientific publishing. He was for many years an enthusiastic supporter of European physics journals, particularly those produced by North-Holland, now Elsevier. He was in particular an energetic and supremely fair editor of Physics Letters B, and founding editor of Physics Reports.

During the 1990s, Maurice placed his intimate knowledge of the European physics scene at the service of CERN by assisting Chris Llewellyn Smith as his advisor for relations with the Member States. He traveled energetically, consulted widely and served the particle physics community assiduously as an invaluable contact between the organization and its many stakeholders, during a difficult period while approval and funding for the LHC were being secured.

Subsequently, Maurice returned to relative tranquility in the Theory Division. Unfortunately, he was struck by a chronic and debilitating ailment that made it difficult for him to enjoy to the full his richly deserved retirement. Nevertheless, he maintained his unfailing equanimity and curiosity, and his active interest in physics and CERN matters in general, re-awakening his longstanding interest in relativistic heavy-ion collisions and the quark-gluon plasma - and who better than Maurice to edit a volume celebrating CERN's fiftieth anniversary?

Maurice's many friends around the world have always valued immensely his selfless kindness, his modesty, his lucidity, his energy and his inexhaustible willingness to help, advise and assist them. We will miss him sorely.

With the sudden death of Maurice Jacob, CERN has lost one of its leading figures, the French physics community has lost one of its pillars, the European particle physics community has lost one of its most dedicated servants, his many friends have lost one of their staunchest supports.

Our thoughts at this time are with his wife Lise, his children Jimmy, Thierry, Francis, and Irène, and their families, knowing that their loss is irreparable.

John Ellis