Quantum tomography for collider physics: illustrations with lepton-pair production

Abstract Quantum tomography is a method to experimentally extract all that is observable about a quantum mechanical system. We introduce quantum tomography to collider physics with the illustration of the angular distribution of lepton pairs. The tomographic method bypasses much of the field-theoret...

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Main Authors: John C. Martens, John P. Ralston, J. D. Tapia Takaki
Format: Article
Language:English
Published: SpringerOpen 2017-12-01
Series:European Physical Journal C: Particles and Fields
Online Access:http://link.springer.com/article/10.1140/epjc/s10052-017-5455-8
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spelling doaj-22bf60a712374020a297742855ee086d2020-11-24T23:58:38ZengSpringerOpenEuropean Physical Journal C: Particles and Fields1434-60441434-60522017-12-0178111310.1140/epjc/s10052-017-5455-8Quantum tomography for collider physics: illustrations with lepton-pair productionJohn C. Martens0John P. Ralston1J. D. Tapia Takaki2Department of Physics and Astronomy, The University of KansasDepartment of Physics and Astronomy, The University of KansasDepartment of Physics and Astronomy, The University of KansasAbstract Quantum tomography is a method to experimentally extract all that is observable about a quantum mechanical system. We introduce quantum tomography to collider physics with the illustration of the angular distribution of lepton pairs. The tomographic method bypasses much of the field-theoretic formalism to concentrate on what can be observed with experimental data. We provide a practical, experimentally driven guide to model-independent analysis using density matrices at every step. Comparison with traditional methods of analyzing angular correlations of inclusive reactions finds many advantages in the tomographic method, which include manifest Lorentz covariance, direct incorporation of positivity constraints, exhaustively complete polarization information, and new invariants free from frame conventions. For example, experimental data can determine the entanglement entropy of the production process. We give reproducible numerical examples and provide a supplemental standalone computer code that implements the procedure. We also highlight a property of complex positivity that guarantees in a least-squares type fit that a local minimum of a $$\chi ^{2}$$ χ2 statistic will be a global minimum: There are no isolated local minima. This property with an automated implementation of positivity promises to mitigate issues relating to multiple minima and convention dependence that have been problematic in previous work on angular distributions.http://link.springer.com/article/10.1140/epjc/s10052-017-5455-8
collection DOAJ
language English
format Article
sources DOAJ
author John C. Martens
John P. Ralston
J. D. Tapia Takaki
spellingShingle John C. Martens
John P. Ralston
J. D. Tapia Takaki
Quantum tomography for collider physics: illustrations with lepton-pair production
European Physical Journal C: Particles and Fields
author_facet John C. Martens
John P. Ralston
J. D. Tapia Takaki
author_sort John C. Martens
title Quantum tomography for collider physics: illustrations with lepton-pair production
title_short Quantum tomography for collider physics: illustrations with lepton-pair production
title_full Quantum tomography for collider physics: illustrations with lepton-pair production
title_fullStr Quantum tomography for collider physics: illustrations with lepton-pair production
title_full_unstemmed Quantum tomography for collider physics: illustrations with lepton-pair production
title_sort quantum tomography for collider physics: illustrations with lepton-pair production
publisher SpringerOpen
series European Physical Journal C: Particles and Fields
issn 1434-6044
1434-6052
publishDate 2017-12-01
description Abstract Quantum tomography is a method to experimentally extract all that is observable about a quantum mechanical system. We introduce quantum tomography to collider physics with the illustration of the angular distribution of lepton pairs. The tomographic method bypasses much of the field-theoretic formalism to concentrate on what can be observed with experimental data. We provide a practical, experimentally driven guide to model-independent analysis using density matrices at every step. Comparison with traditional methods of analyzing angular correlations of inclusive reactions finds many advantages in the tomographic method, which include manifest Lorentz covariance, direct incorporation of positivity constraints, exhaustively complete polarization information, and new invariants free from frame conventions. For example, experimental data can determine the entanglement entropy of the production process. We give reproducible numerical examples and provide a supplemental standalone computer code that implements the procedure. We also highlight a property of complex positivity that guarantees in a least-squares type fit that a local minimum of a $$\chi ^{2}$$ χ2 statistic will be a global minimum: There are no isolated local minima. This property with an automated implementation of positivity promises to mitigate issues relating to multiple minima and convention dependence that have been problematic in previous work on angular distributions.
url http://link.springer.com/article/10.1140/epjc/s10052-017-5455-8
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