MURRAY GELL-MANN

Murray Gell-Mann was born September 15, 1929 in New York and was the youngest son of immigrants from Austria, Arthur and Pauline (Rayhshtayn) Gell-Mann. At the age of fifteen years, Murray enrolled at Yale University and graduated with honors in 1948 with a bachelor of arts degree. The following years he spent in graduate Massachusetts Institute of Technology. Here, in 1951, Gell-Mann received his doctorate in physics. After a year′s stay at the Princeton Institute for Basic Research (New Jersey), Gell-Mann joined the University of Chicago with Enrico Fermi, first teacher (1952-1953), then assistant professor (1953-1954) and Associate Professor (1954 -- 1955).

The main area of scientific interests of the young scientist - physics of elementary particles - in the fifties was in the formative stage. The principal means of experimental research in the department of physics were boosters, "slingshot" particle beam in fixed target: the collision of incident particles with the target source of new particles. With the help of accelerators experimenters managed to get several new types of elementary particles, besides the already known protons, neutrons and electrons. Theoretical physicists have tried to find a scheme that would classify all the new particles.

Scientists have discovered particles with the unusual (strange) behavior. The rate of birth of such particles as a result of some of the clashes showed that their behavior is determined by the strong interaction, which is characterized by speed. Strong, weak, electromagnetic and gravitational interactions are comprised of four types of interaction that underlie all phenomena. However, strange particles decayed unusually long time, that it would be impossible if their behavior is determined by the strong interaction. The decay rate "strange" particles, seems to point to the fact that this process is determined by a much weaker interaction.

Photo — «Murray Gell-mann»

In addressing this daunting task, and focused Gell-Mann. The starting point of his theories, he chose the concept, known as charge independence. Its essence is a definite group of particles, emphasizing their similarities. For example, despite the fact that the proton and neutron are different electric charge (a proton has a charge of +1, the neutron - 0) in all other respects they are identical. Consequently, they are the two varieties of the same type of particles called nucleons, with an average charge, or center of charge, equal to 1 / 2. It is often said that the proton and neutron form a doublet. Other particles may also be included in a similar doublets or in groups of three particles, called triplets, or "group", consisting of only one particle - singlets. General name of the group consisting of any number of particles - multiplet.

All attempts to group the "strange" particles similarly unsuccessful. In formulating its scheme of their grouping, Gell-Mann found that the average charge of their multiplets is different from the average charge of the nucleons. He came to the conclusion that this difference may be a fundamental property of "strange" particles, and proposed to introduce a new quantum property, called "strangeness. " For reasons of algebraic nature of the strangeness of a particle is equal to twice the difference between the average charge of the multiplet and the average charge of the nucleons + 1 / 2. Gell-Mann showed that the "strangeness" is conserved in all reactions, which involve the strong interaction. In other words, the sum of "strangeness" of all the particles to the strong interaction should be absolutely equal to the aggregate "strangeness" of all the particles after the interaction.

Maintaining a "singularity" explains why the decay of such particles can not be determined by the strong interaction.

Photo — «Murray Gell-mann»

In a collision of some other, not "strange" particles "strange" particles are in pairs. This "strangeness" of one particle compensates "strangeness" of another. For example, if one particle in the pair is "strangeness" +1, the "strangeness" of the other is -1. That is why the total strangeness of strange particles, both before and after the collision is equal to 0. After the birth of "strange" particles scatter. Isolated "strange" particle can not decay due to the strong interaction, if the products of its decay must be a particle with zero strangeness ", since such decay would violate the conservation of" strangeness ". Gell-Mann showed that the electromagnetic interaction (the characteristic time of which entered into between the ages of strong and weak interactions) also retains "strangeness". Thus, strange particles, born, survived until the collapse determined the weak interaction, which does not preserve the "strangeness". His ideas scientist published in 1953.

In 1955, Gell-Mann, married Margaret J. Dow, which was an archaeologist. They had a son and a daughter.

In 1955, Gell-Mann was an adjunct professor at the Faculty of California Institute of Technology, in the following year he became a full professor and in 1967 became an honorary professor′s office, established in memory of Robert A. Millikan.

In 1961, Gell-Mann found that the system of multiplets, he proposed to describe the "strange" particles, may be included in a much more general theoretical framework that enabled him to group all strongly interacting particles in the "family". His scheme scientist called eightfold way (by analogy with the eight attributes of the righteous lives of Buddhism), as some particles were grouped into families, numbering up to eight members.

Photo — «Murray Gell-mann»

His proposed classification scheme of particles is also known as the eightfold symmetry. Soon, regardless of the Gell-Mann, a similar classification of the particles suggested an Israeli physicist Yuval Ne′eman.

Eightfold Path of an American scientist is often compared to the periodic system of chemical elements of Mendeleev, in which the chemical elements with similar properties are grouped into families. Like Mendeleev, who left in the periodic table, some empty cells, predicting the properties of yet unknown elements of the Gell-Mann has left vacancies in some families of particles, suggesting some particles with the right set of properties to fill the "emptiness". His theory received partial confirmation in 1964, after the discovery of one of these particles.

In 1963, while as a visiting professor at the Massachusetts Institute of Technology, Gell-Mann found that the detailed structure of the Eightfold Path can be explained by assuming that each particle participating in the strong interaction, consists of a triplet of particles with a charge constituting a fractional part electric charge of the proton. The same opening came and American physicist George Zweig, who worked at the European Center for Nuclear Research. Gell-Mann called the particles with fractional charge quarks, borrowing a word from the novel by James Joyce′s "Finnegans Wake" ( "Three quarks for Mr. Mark!"). Quarks can have a charge of +2 / 3 or -1 / 3. There are also antiquarks with charges of -2 / 3 or 1 / 3. Neutron, which has no electric charge, consists of a single quark with charge +2 / 3 and two quarks with charge -1 / 3. Proton, which has charge +1, consists of two quarks with charges of +2 / 3 and one quark with charge -1 / 3. Quarks with the same charge may be different other properties, t, there exist several types of quarks with the same charge.

Photo — «Murray Gell-mann»

Different combinations of quarks allow us to describe all strongly interacting particles.

In 1969, the scientist was awarded the Nobel Prize in Physics "for his discoveries concerning the classification of elementary particles and their interactions. Speaking at the award ceremony, Ivar Waller of the Royal Swedish Academy of Sciences noted that the Gell-Mann "for more than a decade, is considered the leading scientist in the field theory of elementary particles. According to Waller, the methods proposed to them, "are among the most powerful tools for further research on the physics of elementary particles.

Among other contributions Gell-Mann in theoretical physics should be noted his suggested together with Richard P. Feynman concept of "current" weak interactions and the subsequent development of "current algebra".

Gell-Mann loves to watch birds and to visit places untouched by civilization. In 1969, the scientist has helped organize a program of environmental research, funded by the National Academy of Sciences of the USA. He is interested in historical linguistics.

Gell-Mann is a member of the American Academy of Arts and Sciences and a foreign member of the Royal Society of London. For his achievements in science before he was awarded the Danny Heineman Prize of the American Physical Society (1959), Prize-winning physicist Ernest Orlando Lawrence Atomic Energy Commission, United States (1966), medals Franklinovskogo Franklin Institute (1967) and John J. Carty medal of the National Academy of Sciences of the USA (1968).