Obituary of Aldo Menzione (1943-2012)

Aldo Menzione, a pioneer in the development and use of silicon vertex detectors, passed away quietly and unexpectedly in Pisa on December 23, 2012. Aldo graduated in Physics at the University of Pisa in 1967. His thesis topic was the ‘Production of Neutral Mesons Decaying into All-neutral Secondaries ', working with the Karlsruhe team at the CERN PS.

In 1969 Aldo joined the Pisa-Stony Brook Collaboration at the CERN ISR. This experiment discovered that the total proton-proton cross section starts increasing at ISR energies, a departure from what previously had appeared to be a flat ‘asymptotic’ behavior. Aldo made important contributions in setting up the experiment and in the study of short-range correlations among particles produced in inelastic collisions, which also were observed by that experiment for the first time as an early manifestation of hadron jets.

In 1978, as a member of the Pisa team, Aldo designed and built the small-angle spectrometer of the NA1 (later NA7) experiment. This spectrometer obtained a number of new results in charm physics and meson form factors. The innovative tracking system of NA7, to which he devoted much of his effort, used a multilayer ‘active target’ of semiconductor strip detectors to identify the decay of long-lived charmed hadrons, allowing measurement of their lifetimes. From this, Aldo understood that a silicon strip vertex detector could be used to signal the decays of charmed and beauty hadrons close to the vacuum pipe at a hadron collider, thereby tagging jets containing heavy flavor.

Starting in 1980, Aldo commenced on the detailed design of the CDF detector at the Tevatron with his characteristic vigor, originality, and vision, focusing on two of the most critical parts, the central tracking system and the central calorimeters. In a chapter of the 1984 CDF Technical Design Report Aldo proposed a multilayer silicon-strip vertex detector for the study of short-lived hadrons, which were expected to play an important role in a number of new phenomena, noticeably the production and decay of the top quark. After many years of careful simulation studies, prototype tests, and internal reviews, the project was approved by the Collaboration and installed in the CDF detector in 1992. Aldo was appointed to lead the SVX construction project. Aldo’s design, changed very little from the original TDR description, played an essential role in the top quark discovery in 1995 by identifying the b-quarks from top decays.

For Run 2 of CDF, an upgraded silicon vertex detector, SVX-II, was implemented with fast front-end trigger electronics, which allowed operating a displaced vertex trigger, the SVT. The SVX-II and SVT played a key role in measurements of fundamental properties of the top quark such as its mass, couplings, decay modes, and production mechanisms. Both the production and properties of hadrons containing bottom and charm quarks also were measured, including the precise measurement of the mixing frequency of the neutral B_s hadrons. Aldo Menzione and Luciano Ristori, the prime designer of SVT, were awarded the Panofsky prize of the APS in 2007 for ‘their leading role in the establishment and use of precision silicon tracking detectors at hadron colliders, enabling broad advances in knowledge of the top quark, b-hadrons, and charm hadrons’ (APS Citation).

Besides being an extremely skilled experimentalist, Aldo was warm, direct, and a wonderful colleague and friend. He participated very actively in physics discussions with crisply thought-out, bluntly expressed, and often deeply original contributions. Aldo created a special atmosphere in which the best decisions were made, and everybody, including the junior members of the Collaboration, felt included.

Because of his weakened health in 2006 he gave up his long-time leadership of the Pisa-CDF group, and had reduced his presence at Fermilab. He will be remembered with deep admiration and love by all his former CDF collaborators, as well as his friends from the time of the ISR and NA1.