Dijets with a large rapidity separation in the next-to-leading order BFKL formalism for searches of large extra dimensions at colliders

Search for the gravity with large extra dimensions at collider energies is considered in the trans-Planckian eikonal regime, i.e., when s ^ ≫ M D ≫ − t ^ . Here s ^ and t ^ are the Mandelstam variables of colliding parton-parton system and M D is the Planck mass scale in the space-time with compactified n D extra dimensions. A relevant observable for this regime may be the cross section of high-mass ( M j j ∼ s ^ ≫ M D ) dijet production with a large rapidity separation. Then the standard model background should be calculated within the next-to-leading logarithmic (NLL) approximation of Balitsky-Fadin-Kuraev-Lipatov (BFKL) formalism of quantum chromodynamics (QCD) suitable for s ^ ≫ − t ^ ≫ Λ QCD . In this work the signal of the large extra dimension gravity as well as the NLL BFKL QCD background are estimated for the high-luminosity Large Hadron Collider (HL-LHC) and future colliders such as FCCpp and CEPC-SppC.