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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Series: | European Physical Journal C: Particles and Fields |
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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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