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Initial condition for the Balitsky-Kovchegov equation at next-to-leading order

Carlisle Casuga1,2,*, Henri Hänninen3,†, and Heikki Mäntysaari1,2,‡

  • *Contact author: carlisle.doc.casuga@jyu.fi
  • †Contact author: henri.j.hanninen@jyu.fi
  • ‡Contact author: heikki.mantysaari@jyu.fi
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Phys. Rev. D 112, 034003 – Published 4 August, 2025

DOI: https://doi.org/10.1103/54zd-hyvg

Abstract

We determine the initial condition of the Balitsky-Kovchegov (BK) evolution equation at next-to-leading order (NLO) accuracy using HERA deep inelastic scattering data. We use Bayesian inference to compare model values, derived from NLO impact factors and the BK evolution equation with kinematical constraint resumming most important higher order corrections, to precise data and to extract posterior distributions characterizing the initial condition. The total cross section and charm quark production data from HERA are found to provide stringent constraints on the posterior. These distributions quantify the uncertainty in the initial condition and serve as necessary input for propagating uncertainties to all NLO calculations within the color glass condensate framework.

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Phys. Rev. D 112, 034003– Published 4 August, 2025
  • Received 17 June 2025
  • Accepted 15 July 2025
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