Cubic Representations of Open-String Effective Action Contact Terms and BCJ Relations at Four-Point One-Loop
The tree amplitudes of string theory low-energy effective actions admit a diagrammatic expansion in terms of higher-than-cubic contact terms. These tree amplitudes can be used to build loop amplitudes using unitary cuts or the forward limit. In this thesis we study the possibility of constructing fo...
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Uppsala universitet, Teoretisk fysik
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ndltd-UPSALLA1-oai-DiVA.org-uu-4568742021-10-29T05:29:26ZCubic Representations of Open-String Effective Action Contact Terms and BCJ Relations at Four-Point One-LoopengMicah, TegeviUppsala universitet, Teoretisk fysik2021Scattering AmplitudesColor-KinematicsOther Physics TopicsAnnan fysikThe tree amplitudes of string theory low-energy effective actions admit a diagrammatic expansion in terms of higher-than-cubic contact terms. These tree amplitudes can be used to build loop amplitudes using unitary cuts or the forward limit. In this thesis we study the possibility of constructing four-point cubic representations for the resulting one-loop contact terms that obey the Bern-Carrasco-Johansson (BCJ) color-kinematics relation. From the string theory effective action we study the contact terms carrying ζ2, ζ3, ζ4, and ζ5. For the even ζ2 and ζ4 cases we find that the cubic representations are incompatible with the BCJ relations, as expected from their disappearance in the closed-string effective action. We find a unique, local set of numerators at ζ3 that obey the BCJ relations. For ζ5 we find two choices of representations: one obeys BCJ but requires non-trivial contributions for the tadpole; the other contains no tadpoles but breaks one of the BCJ relations. Student thesisinfo:eu-repo/semantics/bachelorThesistexthttp://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-456874FYSAST ; FYSMAS1170application/pdfinfo:eu-repo/semantics/openAccess |
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Scattering Amplitudes Color-Kinematics Other Physics Topics Annan fysik |
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Scattering Amplitudes Color-Kinematics Other Physics Topics Annan fysik Micah, Tegevi Cubic Representations of Open-String Effective Action Contact Terms and BCJ Relations at Four-Point One-Loop |
description |
The tree amplitudes of string theory low-energy effective actions admit a diagrammatic expansion in terms of higher-than-cubic contact terms. These tree amplitudes can be used to build loop amplitudes using unitary cuts or the forward limit. In this thesis we study the possibility of constructing four-point cubic representations for the resulting one-loop contact terms that obey the Bern-Carrasco-Johansson (BCJ) color-kinematics relation. From the string theory effective action we study the contact terms carrying ζ2, ζ3, ζ4, and ζ5. For the even ζ2 and ζ4 cases we find that the cubic representations are incompatible with the BCJ relations, as expected from their disappearance in the closed-string effective action. We find a unique, local set of numerators at ζ3 that obey the BCJ relations. For ζ5 we find two choices of representations: one obeys BCJ but requires non-trivial contributions for the tadpole; the other contains no tadpoles but breaks one of the BCJ relations. |
author |
Micah, Tegevi |
author_facet |
Micah, Tegevi |
author_sort |
Micah, Tegevi |
title |
Cubic Representations of Open-String Effective Action Contact Terms and BCJ Relations at Four-Point One-Loop |
title_short |
Cubic Representations of Open-String Effective Action Contact Terms and BCJ Relations at Four-Point One-Loop |
title_full |
Cubic Representations of Open-String Effective Action Contact Terms and BCJ Relations at Four-Point One-Loop |
title_fullStr |
Cubic Representations of Open-String Effective Action Contact Terms and BCJ Relations at Four-Point One-Loop |
title_full_unstemmed |
Cubic Representations of Open-String Effective Action Contact Terms and BCJ Relations at Four-Point One-Loop |
title_sort |
cubic representations of open-string effective action contact terms and bcj relations at four-point one-loop |
publisher |
Uppsala universitet, Teoretisk fysik |
publishDate |
2021 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-456874 |
work_keys_str_mv |
AT micahtegevi cubicrepresentationsofopenstringeffectiveactioncontacttermsandbcjrelationsatfourpointoneloop |
_version_ |
1719491731370541056 |