HERA data and collinearly-improved BK dynamics

B. Ducloué (1) , E. Iancu (1) , G. Soyez (1) , D.N. Triantafyllopoulos

1 IPHT - Institut de Physique Théorique - UMR CNRS 3681

Within the framework of the dipole factorisation, we use a recent collinearly-improved version of the Balitsky-Kovchegov equation to fit the HERA data for inclusive deep inelastic scattering at small Bjorken x . The equation includes an all-order resummation of double and single transverse logarithms and running coupling corrections. Compared to similar equations previously proposed in the literature, this work makes a direct use of Bjorken x as the rapidity scale for the evolution variable. We obtain excellent fits for reasonable values for the four fit parameters. We find that the fit quality improves when including resummation effects and a physically-motivated initial condition. In particular, the resummation of the DGLAP-like single transverse logarithms has a sizeable impact and allows one to extend the fit up to relatively large photon virtuality Q2 .

Mots clés: DGLAP equation; data analysis method; dipole; quality; evolution equation; rapidity; factorization; boundary condition; Balitsky-Kovchegov equation; DESY HERA Stor; resummation; coupling constant: energy dependence; small-x; Deep inelastic scattering; deep inelastic scattering: inclusive reaction; Parton saturation; Deep Inelastic Scattering; QCD

Domaines: Physique des Hautes Energies - Phénoménologie [hep-ph]

B. Ducloué, E. Iancu, G. Soyez, D.N. Triantafyllopoulos. HERA data and collinearly-improved BK dynamics. Phys.Lett.B, 2020, 803, pp.135305. ⟨10.1016/j.physletb.2020.135305⟩. ⟨hal-02447834⟩