Small x phenomenology on gluon evolution through the BFKL equation in light of a constraint in multi-Regge kinematics

Abstract

We investigate the impact of so-called kinematic constraint on gluon evolution at small x. Implanting the constraint on the real emission term of the gluon ladder diagram, we obtain an integro-differential form of the Balitsky-Fadin-Kuraev-Lipatov (BFKL) equation. Later we solve the equation analytically using the method of characteristics. We sketch the Bjorken x and transverse momentum dependence of our solution of unintegrated gluon distributions in the kinematic constraint supplemented BFKL equation and contrasted the same with the original BFKL equation. Then we extract the integrated gluon density xg(x, Q2) from unintegrated gluon distributions and compared our theoretical prediction with that of global data fits, namely NNPDF3.1sx and CT14. Finally we illustrate the phenomenological implication of our solution for unintegrated gluon distribution towards exploring high precision HERA DIS data by the theoretical prediction of proton structure functions (F2 and FL).