Iancu E, Mueller A H, Triantafyllopoulos D N
Université Paris-Saclay, CNRS, CEA, Institut de physique théorique, F-91191, Gif-sur-Yvette, France.
Department of Physics, Columbia University, New York, New York 10027, USA.
Phys Rev Lett. 2022 May 20;128(20):202001. doi: 10.1103/PhysRevLett.128.202001.
We demonstrate that hard dijet production via coherent inelastic diffraction is a promising channel for probing gluon saturation at the Electron-Ion Collider. By inelastic diffraction, we mean a process in which the two hard jets-a quark-antiquark pair generated by the decay of the virtual photon-are accompanied by a softer gluon jet, emitted by the quark or the antiquark. This process can be described as the elastic scattering of an effective gluon-gluon dipole. The cross section takes a factorized form, between a hard factor and a unintegrated ("Pomeron") gluon distribution describing the transverse momentum imbalance between the hard dijets. The dominant contribution comes from the black disk limit and leads to a dijet imbalance of the order of the target saturation momentum Q_{s} evaluated at the rapidity gap. Integrating out the dijet imbalance, we obtain a collinear factorization where the initial condition for the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution is set by gluon saturation.
我们证明，通过相干非弹性衍射产生硬双喷注是在电子-离子对撞机上探测胶子饱和的一个有前景的途径。通过非弹性衍射，我们指的是这样一个过程：两个硬喷注——由虚光子衰变产生的夸克-反夸克对——伴随着一个由夸克或反夸克发射的较软的胶子喷注。这个过程可以描述为一个有效胶子-胶子偶极子的弹性散射。截面具有一种因子化形式，介于一个硬因子和一个描述硬双喷注之间横向动量不平衡的未积分（“坡密子”）胶子分布之间。主要贡献来自黑盘极限，并导致在快度间隙处评估的目标饱和动量(Q_{s})量级的双喷注不平衡。对双喷注不平衡进行积分，我们得到一种共线因子化，其中多克希泽-格里博夫-利帕托夫-阿尔塔雷利-帕里西演化的初始条件由胶子饱和设定。
