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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Born-Oppenheimer approximation in an effective field theory language

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Brambilla, Nora [1, 2] ; Krein, Gastao [3] ; Castella, Jaume Tarrus [2] ; Vairo, Antonio [2]
Total Authors: 4
[1] Tech Univ Munich, Inst Adv Study, Lichtenbergstr 2a, D-85748 Garching - Germany
[2] Tech Univ Munich, Phys Dept, James Franck Str 1, D-85748 Garching - Germany
[3] Univ Estadual Paulista, Inst Fis Teor, Rua Dr Bento Teobaldo Ferraz, 271 Bloco 2, BR-01140070 Sao Paulo, SP - Brazil
Total Affiliations: 3
Document type: Journal article
Source: Physical Review D; v. 97, n. 1 JAN 25 2018.
Web of Science Citations: 9

The Born-Oppenheimer approximation is the standard tool for the study of molecular systems. It is founded on the observation that the energy scale of the electron dynamics in a molecule is larger than that of the nuclei. A very similar physical picture can be used to describe QCD states containing heavy quarks as well as light-quarks or gluonic excitations. In this work, we derive the Born-Oppenheimer approximation for QED molecular systems in an effective field theory framework by sequentially integrating out degrees of freedom living at energies above the typical energy scale where the dynamics of the heavy degrees of freedom occurs. In particular, we compute the matching coefficients of the effective field theory for the case of the H-2(+) diatomic molecule that are relevant to compute its spectrum up to O(m alpha(5)) thorn. Ultrasoft photon loops contribute at this order, being ultimately responsible for the molecular Lamb shift. In the effective field theory the scaling of all the operators is homogeneous, which facilitates the determination of all the relevant contributions, an observation that may become useful for high-precision calculations. Using the above case as a guidance, we construct under some conditions an effective field theory for QCD states formed by a color-octet heavy quark-antiquark pair bound with a color-octet light-quark pair or excited gluonic state, highlighting the similarities and differences between the QED and QCD systems. Assuming that the multipole expansion is applicable, we construct the heavy-quark potential up to next-to-leading order in the multipole expansion in terms of nonperturbative matching coefficients to be obtained from lattice QCD. (AU)

FAPESP's process: 13/01907-0 - São Paulo Research and Analysis Center
Grantee:Sergio Ferraz Novaes
Support type: Research Projects - Thematic Grants
FAPESP's process: 13/50841-1 - Charmed hadrons at the confinement scale: structure and interactions with matter
Grantee:Gastão Inácio Krein
Support type: Regular Research Grants