On enhanced corrections from quasi-degenerate states to heavy quarkonium observables
It is well known that in perturbation theory existence of quasi-degenerate states can rearrange the order counting. For a heavy quarkonium system, naively, enhanced effects (l-changing mixing effects) could contribute already to the first-order and third-order corrections to the wave function and th...
Main Authors: | , , |
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Format: | Article |
Language: | English |
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Elsevier
2016-10-01
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Series: | Physics Letters B |
Online Access: | http://www.sciencedirect.com/science/article/pii/S0370269316304464 |
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author | Y. Kiyo G. Mishima Y. Sumino |
author_facet | Y. Kiyo G. Mishima Y. Sumino |
author_sort | Y. Kiyo |
collection | DOAJ |
description | It is well known that in perturbation theory existence of quasi-degenerate states can rearrange the order counting. For a heavy quarkonium system, naively, enhanced effects (l-changing mixing effects) could contribute already to the first-order and third-order corrections to the wave function and the energy level, respectively, in expansion in αs. We present a formulation and note that the corresponding (lowest-order) corrections vanish due to absence of the relevant off-diagonal matrix elements. As a result, in the quarkonium energy level and leptonic decay width, the enhanced effects are expected to appear, respectively, in the fifth- and fourth-order corrections and beyond. |
first_indexed | 2024-12-20T19:40:16Z |
format | Article |
id | doaj.art-d6a06ad0ea9f4f49a9e82d3cb942702b |
institution | Directory Open Access Journal |
issn | 0370-2693 1873-2445 |
language | English |
last_indexed | 2024-12-20T19:40:16Z |
publishDate | 2016-10-01 |
publisher | Elsevier |
record_format | Article |
series | Physics Letters B |
spelling | doaj.art-d6a06ad0ea9f4f49a9e82d3cb942702b2022-12-21T19:28:33ZengElsevierPhysics Letters B0370-26931873-24452016-10-01761C18418910.1016/j.physletb.2016.08.026On enhanced corrections from quasi-degenerate states to heavy quarkonium observablesY. Kiyo0G. Mishima1Y. Sumino2Department of Physics, Juntendo University, Inzai, Chiba 270-1695, JapanDepartment of Physics, Tohoku University, Sendai, 980-8578, JapanDepartment of Physics, Tohoku University, Sendai, 980-8578, JapanIt is well known that in perturbation theory existence of quasi-degenerate states can rearrange the order counting. For a heavy quarkonium system, naively, enhanced effects (l-changing mixing effects) could contribute already to the first-order and third-order corrections to the wave function and the energy level, respectively, in expansion in αs. We present a formulation and note that the corresponding (lowest-order) corrections vanish due to absence of the relevant off-diagonal matrix elements. As a result, in the quarkonium energy level and leptonic decay width, the enhanced effects are expected to appear, respectively, in the fifth- and fourth-order corrections and beyond.http://www.sciencedirect.com/science/article/pii/S0370269316304464 |
spellingShingle | Y. Kiyo G. Mishima Y. Sumino On enhanced corrections from quasi-degenerate states to heavy quarkonium observables Physics Letters B |
title | On enhanced corrections from quasi-degenerate states to heavy quarkonium observables |
title_full | On enhanced corrections from quasi-degenerate states to heavy quarkonium observables |
title_fullStr | On enhanced corrections from quasi-degenerate states to heavy quarkonium observables |
title_full_unstemmed | On enhanced corrections from quasi-degenerate states to heavy quarkonium observables |
title_short | On enhanced corrections from quasi-degenerate states to heavy quarkonium observables |
title_sort | on enhanced corrections from quasi degenerate states to heavy quarkonium observables |
url | http://www.sciencedirect.com/science/article/pii/S0370269316304464 |
work_keys_str_mv | AT ykiyo onenhancedcorrectionsfromquasidegeneratestatestoheavyquarkoniumobservables AT gmishima onenhancedcorrectionsfromquasidegeneratestatestoheavyquarkoniumobservables AT ysumino onenhancedcorrectionsfromquasidegeneratestatestoheavyquarkoniumobservables |