N-pi Decays of Baryons in a Relativized Model
N-pi Decays of Baryons in a Relativized Model

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Published: 1992

Total Pages: 1994

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We calculate teh N pi decay amplitudes of baryon resonances ina semi-relativistic version of the 3P0 model of hadron decays. We use relativized wave functions for the baryons and mesons, and include an intuitive modification of the usual 3P0 model. Our results are in reasonable agreement with the reported amplitudes for all known non-strange resonances, and confirm a proposed solution to the mystery of the 'missing' states.

Quasi Two-body Decays of Nonstrange Baryons
Quasi Two-body Decays of Nonstrange Baryons

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Published: 1993

Total Pages: 17

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We examine the decays of nonstrange baryons to the final states Delta Pi, NRho, NEta, NEta', Nw, N.5 (1440)Pi, and Delta 3/2+(1600)Pi, in a relativized pair-creation (^3Po) model which has been developed in a previous study of the NPi decays of the same baryon states. As it is our goal to provide a guide for the possible discovery of new baryon states at CEBAF and elsewhere, we examine the decays of resonances which have already been seen in the partial-wave analyses, along with those of states which are predicted by the quark model but which remain undiscovered. The level of agreement between our calculation and the available widths from the partial-wave analyses in encouraging.

Strange Decays of Nonstrange Baryons
Strange Decays of Nonstrange Baryons

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Published: 1998

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The strong decays of excited nonstrange baryons into the final states [Lambda]K, [Sigma]K, and for the first time into [Lambda](1405)K, [Lambda](1520)K, [Sigma](1385)K, [Lambda]K{sup *}, and [Sigma]K{sup *}, are examined in a relativized quark pair creation model. The wave functions and parameters of the model are fixed by previous calculations of N[pi] and N[pi][pi], etc., decays. The results show that it should be possible to discover several new negative parity excited baryons and confirm the discovery of several others by analyzing these final states in kaon production experiments. They also establish clear predictions for the relative strengths of certain states to decay to [Lambda](1405)K and [Lambda](1520)K, which can be tested to determine if a three-quark model of the [Lambda](1405)K is valid. The authors results compare favorably with the results of partial wave analyses of the limited existing data for the [Lambda]K and [Sigma]K channels. They do not find large [Sigma]K decay amplitudes for a substantial group of predicted and weakly established negative-parity states, in contrast to the only previous work to consider decays of these states into the strange final states [Lambda]K and [Sigma]K.

100 Years of Relativity
100 Years of Relativity

Author: Abhay Ashtekar

Publisher: World Scientific

Published: 2005

Total Pages: 527

ISBN-13: 9812700986

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Thanks to Einstein''s relativity theories, our notions of space and time underwent profound revisions about a 100 years ago. The resulting interplay between geometry and physics has dominated all of fundamental physics since then. This volume contains contributions from leading researchers, worldwide, who have thought deeply about the nature and consequences of this interplay. The articles take a long-range view of the subject and distill the most important advances in broad terms, making them easily accessible to non-specialists. The first part is devoted to a summary of how relativity theories were born (J Stachel). The second part discusses the most dramatic ramifications of general relativity, such as black holes (P Chrusciel and R Price), space-time singularities (H Nicolai and A Rendall), gravitational waves (P Laguna and P Saulson), the large scale structure of the cosmos (T Padmanabhan); experimental status of this theory (C Will) as well as its practical application to the GPS system (N Ashby). The last part looks beyond Einstein and provides glimpses into what is in store for us in the 21st century. Contributions here include summaries of radical changes in the notions of space and time that are emerging from quantum field theory in curved space-times (Ford), string theory (T Banks), loop quantum gravity (A Ashtekar), quantum cosmology (M Bojowald), discrete approaches (Dowker, Gambini and Pullin) and twistor theory (R Penrose).

The Joy of Discovery
The Joy of Discovery

Author: Walter Thirring

Publisher: World Scientific

Published: 2011

Total Pages: 207

ISBN-13: 9814322962

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Walter Thirring is the last offspring of an Austrian family of scientists. In this moving narrative, he describes how he survived the Nazi occupation and became instrumental in reconstructing European science. Thirring is one of the last living physicists who worked on the greatest discoveries and with the greatest scientists of the 20th century. He recollects encounters with the old masters like Einstein, Schr™dinger, Heisenberg, Pauli and others as well as his collaborations with the present stars like Murray Gell-Mann and Elliott Lieb. The book presents the challenges faced when one of the major paradigm shifts took place, namely, the shift away from atomistic theory and Newtonian physics towards field theory and quantum mechanics. Every step is presented in clear, understandable language which reflects Thirring's extensive experience in training the next generation. Additionally, Thirring describes his fascinating and profound life experiences, growing up under Nazi occupation, serving in the war, striving to establish scientific excellence and in reaching out across the Iron Curtain. A true Renaissance man, he concludes by discussing his love of music, and it is clear that his passion for learning is only matched by his passion for music, a sampling of which can be found at http://phaidra.univie.ac.at/o:1459. A work that inspires at every junction and is decisively re-readable, Thirring's autobiography is assuredly a must-have for anyone interested in science, physics and history.