Penguin diagrams are a class of Feynman diagrams in quantum field theory that allow one to understand charge parity violation in the standard model . They describe a one-loop process in which a quark temporarily changes flavor , while participating in some kind of interaction described by a tree diagram.
For those interactions in which some quark flavors (for example, very heavy) have much higher interaction amplitudes than others - for example, Higgs interactions or interactions that violate CP symmetry - penguin diagrams can make a comparable or even larger contribution wood diagrams. A similar scheme can be applied to lepton decay [1] .
Title
The American physicist was the first to introduce the name “penguin diagrams” for this class of quantum field theory diagrams, partly because of their shape, partly because of the bet lost to Melissa Franklin. Since 1976, Ellis worked at CERN along with Mary K. Galard and Dimitris Nanopoulos on the processes described by penguin diagrams. In the spring of 1977, Ellis, Mike Chanowitz, Marie Galard, working on the theory of the great unification , wrote an article in which they predicted the mass of the b-quark . In the summer of the same year, John went with his friends to a bar, where he lost the game of darts to Melissa Franklin (although it was replaced by Serge Rudaz). Under the terms of the bet, the loser had to insert the word “penguin” in his next scientific article [2] . According to John Ellis, the idea of how to use the word "penguin" in his article came to his mind while smoking a forbidden plant.
History
Introduced by Russian theoretical physicists Mikhail Shifman , Arkady Weinstein and Valentin Zakharov [3] . The processes described by these diagrams were first observed by the CLEO collaboration at Cornell University ( USA ) in 1991 and 1994.
Notes
- ↑ Dissecting the Penguin // Quantum Diaries.
- ↑ Mikhail Shifman (1995), "ITEP Lectures in Particle Physics", arΧiv : hep-ph / 9510397 [hep-ph]
- ↑ JETP Letters 22 , 55 (1975); Nucl. Phys. B 120 , 316 (1977)
Literature
- him. Hartmut Machner: Einführung in die Kern - und Elementarteilchenphysik. Wiley-VCH, Weinheim 2005, ISBN 3-527-40528-3 , S. 384.
- him. Uwe Reichert: Pinguine im Teilchenzoo. In: Spektrum der Wissenschaft. Nr. 4, 1994, S. 24 (Vorschau).
- him. P. Koppenburg, Z. Dolezal, M. Smizanska: Rare decays of b hadrons. In: Scholarpedia. Band 11, Nr. 6, 2016, S. 32643., doi: 10.4249 / scholarpedia.32643.