Abstract
We perform the renormalization group improved collinear resummation of the photon-gluon impact factors. We construct the resummed cross section for virtual photon-photon (γ∗γ∗) scattering which incorporates the impact factors and BFKL gluon Green’s function up to the next-to-leading logarithmic accuracy in energy. The impact factors include important kinematical effects which are responsible for the most singular poles in Mellin space at next-to-leading order. Further conditions on the resummed cross section are obtained by requiring the consistency with the collinear limits. Our analysis is consistent with previous impact factor calculations at NLO, apart from a new term proportional to CF that we find for the longitudinal polarization. Finally, we use the resummed cross section to compare with the LEP data on the γ∗γ∗ cross section and with previous calculations. The resummed result is lower than the leading logarithmic approximation but higher than the pure next-to-leading one, and is consistent with the experimental data.
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Acknowledgments
We thank Ian Balitsky and Stefano Catani for the discussions. This project is supported by the U.S. Department of Energy Grant DE-SC-0002145 and within the framework of the Saturated Glue (SURGE) Topical Theory Collaboration, by Polish NCN Grant No. 2019/33/B/ST2/02588, and by the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 824093.
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Colferai, D., Li, W. & Staśto, A.M. Renormalization group improved photon impact factors and the high energy virtual photon scattering. J. High Energ. Phys. 2024, 106 (2024). https://doi.org/10.1007/JHEP01(2024)106
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DOI: https://doi.org/10.1007/JHEP01(2024)106