André Lagarrigue (1924 – 14 January 1975) was a French

particle physicist Particle physics or high energy physics is the study of Elementary particle, fundamental particles and fundamental interaction, forces that constitute matter and radiation. The fundamental particles in the universe are classified in the Standa ...

. Being the initiator of the Gargamelle experiment at

CERN The European Organization for Nuclear Research, known as CERN (; ; ), is an intergovernmental organization that operates the largest particle physics laboratory in the world. Established in 1954, it is based in a northwestern suburb of Gene ...

, his work was of paramount importance in the discovery of

neutral currents Weak neutral current interactions are one of the ways in which subatomic particles can interact by means of the weak force. These interactions are mediated by the Z boson. The discovery of weak neutral currents was a significant step towa ...

— the first experimental indication of the existence of the Z⁰ boson. This major discovery was a step towards verification of the electroweak theory, today a pillar of the

Standard Model The Standard Model of particle physics is the theory describing three of the four known fundamental forces (electromagnetism, electromagnetic, weak interaction, weak and strong interactions - excluding gravity) in the universe and classifying a ...

Career and research

Born in

Aurillac Aurillac (; oc, Orlhac ) is the prefecture of the Cantal department, in the Auvergne-Rhône-Alpes region of France. The inhabitants of the commune are known as ''Aurillacois'' or ''Aurillacoises''. Geography Aurillac is at above sea leve ...

, France, André Lagarrigue was admitted to

École Polytechnique École may refer to: * an elementary school in the French educational stages normally followed by secondary education establishments (collège and lycée) * École (river), a tributary of the Seine flowing in région Île-de-France * École, Savoi ...

in Paris in 1945, specializing in the field of weapons engineering. However, while still a student at

he was attracted to the field of experimental physics, and participated in an experiment designed to determine the mass of the

muon A muon ( ; from the Greek letter mu (μ) used to represent it) is an elementary particle similar to the electron, with an electric charge of −1 '' e'' and a spin of , but with a much greater mass. It is classified as a lepton. As wi ...

using a cloud chamber. In 1952 he achieved a doctorate from the Sorbonne University on the experimental properties of

muon decay A muon ( ; from the Greek letter mu (μ) used to represent it) is an elementary particle similar to the electron, with an electric charge of −1 '' e'' and a spin of , but with a much greater mass. It is classified as a lepton. As wit ...

. Between 1954 and 1955 he spent a sabbatical year at

Berkeley Berkeley most often refers to: *Berkeley, California, a city in the United States **University of California, Berkeley, a public university in Berkeley, California * George Berkeley (1685–1753), Anglo-Irish philosopher Berkeley may also refer ...

, where he learnt of the experimental possibilities using

particle accelerators A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to very high speeds and energies, and to contain them in well-defined beams. Large accelerators are used for fundamental research in particle ...

such as the Bevatron. After his return to France and École Polytechnique, he turned his focus towards bubble chambers, becoming renowned for his work on heavy liquid bubble chambers in a time where most physicist worked with

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...

bubble chambers. Hydrogen bubble chambers would provide a pure proton target and consequently better measurements. The heavy liquid bubble chambers would however be cheaper and provide a high density of the target, suitable for neutrino detection, since neutrinos have a very small

cross-section Cross section may refer to: * Cross section (geometry) ** Cross-sectional views in architecture & engineering 3D *Cross section (geology) * Cross section (electronics) * Radar cross section, measure of detectability * Cross section (physics) **Ab ...

. Together with collaborators he constructed several heavy liquid bubble chambers at École Polytechnique. The first chamber built was called BP1, a

propane Propane () is a three-carbon alkane with the molecular formula . It is a gas at standard temperature and pressure, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used a ...

bubble chamber of 1 liter. They first used scattering at small angles, from light coming from the back of the chamber. They then tried to use side illumination at 90°, like in a cloud chamber. This method turned out to be efficient, and was later used in the Gargamelle experiment. A second, bigger chamber, BP2, built for experiments at Saclay, contained 20 liters of a mixture of propane and

methyl iodide Iodomethane, also called methyl iodide, and commonly abbreviated "MeI", is the chemical compound with the formula CH3I. It is a dense, colorless, volatile liquid. In terms of chemical structure, it is related to methane by replacement of one h ...

. He went on to develop BP3. After attending a conference in 1963, on the newest developments in the field of

neutrino physics A neutrino ( ; denoted by the Greek letter ) is a fermion (an elementary particle with spin of ) that interacts only via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is ...

, Lagarrigue came up with the idea to construct a heavy liquid chamber for detection of

neutrinos A neutrino ( ; denoted by the Greek letter ) is a fermion (an elementary particle with spin of ) that interacts only via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is ...

— an idea that would earn him the nickname ''father of Gargamelle''. He wrote the first published proposal for Gargamelle, dated 10 February 1964, and gathered a collaboration consisting of seven laboratories: École Polytechnique Paris, RWTH Aachen, ULB Bruxelles, Istituto di Fisica dell'Università di Milano, LAL Orsay,

University College London , mottoeng = Let all come who by merit deserve the most reward , established = , type = Public research university , endowment = £143 million (2020) , budget = ...

and CERN. During the next years he led the collaboration to many important discoveries, amongst others that of the neutral currents in both

lepton In particle physics, a lepton is an elementary particle of half-integer spin ( spin ) that does not undergo strong interactions. Two main classes of leptons exist: charged leptons (also known as the electron-like leptons or muons), and neutr ...

ic and

hadron In particle physics, a hadron (; grc, ἁδρός, hadrós; "stout, thick") is a composite subatomic particle made of two or more quarks held together by the strong interaction. They are analogous to molecules that are held together by the ele ...

ic events, and the experimental proof of the fractional charges of the

quarks A quark () is a type of elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. All commonly o ...

. Gargamelle turned out to be one of the most significant experiments in the history of CERN. In 1964 he became professor at the University of Orsay. In 1969 he became director of Orsay Linear Accelerator Laboratory, a position he held until his untimely death in 1975. Lagarrigue died of a heart attack, while leaving one of his courses at the University of Orsay.

Awards and honors

* In 1975 Lagarrigue was the second recipient of the

Prize Ampère A prize is an award to be given to a person or a group of people (such as sporting teams and organizations) to recognize and reward their actions and achievements.

, awarded annually by the French Academy of Science. * A prize named in Lagarrigue's honor, The André Lagarrigue Prize, issued by the French Physics Society on the occasion of the 50th jubilee of Orsay Linear Accelerator Laboratory, is awarded annually to a senior

experimental physicist Experimental physics is the category of disciplines and sub-disciplines in the field of physics that are concerned with the observation of physical phenomena and experiments. Methods vary from discipline to discipline, from simple experiments and o ...

working in France. * An auditorium at

in Paris is named in his honor. * Lagarrigue has a

street A street is a public thoroughfare in a built environment. It is a public parcel of land adjoining buildings in an urban context, on which people may freely assemble, interact, and move about. A street can be as simple as a level patch of dirt, ...

named after him at CERN, in the Prévessin site, and a square in the Meyrin site

Career and research

Awards and honors

References

Further reading