Abstract
The next-to-leading order (NLO) P-wave Coulomb Green function contributes at third-order to top-pair production in e+e− collisions near threshold. In this paper we compute the NLO P-wave Green function in dimensional regularization, as required for a consistent combination with non-resonant production of the W+W−bb¯ final state, and present a phenomenological analysis of the P-wave contribution. We further briefly discuss squark production near threshold and top-pair production in γγ collisions, where no S-wave contribution is present, and the P-wave thus constitutes the dominant production process.
Highlights
A future high-energy electron–positron collider will allow a very precise measurement of the top–antitop production cross section near threshold
This can be achieved by successively integrating out the hard and soft scale leading to the non-relativistic QCD (NRQCD) [4,5,6] and potential NRQCD (PNRQCD) [7,8,9,10,11] effective field theories, respectively
The LO Coulomb potential contributes to the same order as the leading kinetic terms in the PNRQCD Lagrangian and has to be treated non-perturbatively, while the next-to-leading order (NLO) correction VC(1) is a perturbation
Summary
A future high-energy electron–positron collider will allow a very precise measurement of the top–antitop production cross section near threshold. In terms of Feynman diagrams, this implies that when the velocity is of order of the strong coupling, Coulomb singularities of the form (αs/v)n have to be summed to all orders This can be achieved by successively integrating out the hard and soft scale leading to the non-relativistic QCD (NRQCD) [4,5,6] and potential NRQCD (PNRQCD) [7,8,9,10,11] effective field theories, respectively.
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